PLANING BOAT WITH FOLDABLE FAIRING

FIELD OF THE INVENTION

[0001]The present invention relates to planing boats and is intended to improve the efficiency of such boats in displacement and transitional motion modes by using transom fairings without significantly increasing the dimensions and not deteriorating the operational properties of the boats in the main high-speed planing mode and at rest.

BACKGROUND OF THE INVENTION

[0002]Various planing boats including runabouts, motor yachts, work boats, patrol boats, etc., which are the subject of this invention, are intended to move in their main operating mode at relatively high speeds with Froude numbers based on displacement:

${\mathrm{Fr}}_D=V/{\left(g·D^{1/3}\right)}^{1/2},$

where “V” is speed, “g” is acceleration due to gravity, and “D” is displacement. This range of relatively high Froude numbers includes Fr_D from about 1 to 3, called the transitional (or semi-planing) mode, in which hydrodynamic pressures on the bottom of the boat make up a significant proportion of the forces supporting the boat on the water (along with the Archimedean forces) and substantially affect the behavior of the boat, and Fr_D greater than 3, corresponding to the full planing mode, in which the support of the boat is provided predominantly (by 95% and more, e.g.) by hydrodynamic lift.

[0003]Lower relative speeds (roughly at Fr_D less than 1) correspond to the displacement mode, in which the boat is kept on the water almost exclusively by Archimedean forces. Efficient generation of dynamic lift to support the boat's weight (to keep the hull out of the water to reduce drag) in planing and semi-planing modes requires substantially flat bottom surfaces with sharp trailing edges to provide flow separation, which presupposes the transom type of the boat's stern forming a distinctive step in its configuration (which is also true for each planing surface of multihull and multiplane boats).

[0004]At the same time, along with the inevitable sailing in displacement mode during acceleration before taking off on plane, in practical operation, planing boats, including planing motor yachts, are often operated in displacement mode of motion for a substantial portion of their period of use (even more than in planing mode).

[0005]This is, in particular, due to the fact that, as a rule, because of a significant reduction in the power required to propel the boat, fuel consumption per mile in displacement mode and even sometimes partially in transitional mode is less than in planing mode, which provides a significantly greater cruising range (at a much lower speed, of course). However, the configuration of a typical planing boat with a sharp trailing edge and a transom stern is far from optimal for the displacement mode of motion, while giving it optimal hull contours for low Froude numbers—without steps and with smoothly rising and tapering stern formations—could significantly reduce resistance, power and fuel consumption and, accordingly, increase efficiency and cruising range.

[0006]On the other hand, smooth, gently rising and tapering stern formations are unacceptable from the point of view of the hydrodynamic efficiency of a planing boat in its principal high-speed mode of motion.

[0007]This dilemma can be resolved by equipping the stern of the boat with a retractable fairing, as, for example, is proposed in inventions U.S. Pat. Nos. 3,614,032 and 6,042,052 in relation to steps of seaplanes, where the fairing, hinged at its aft pat to the fuselage, can rotate, shifting its leading edge vertically, which either exposes the trailing edge of the step, ensuring effective planing during takeoff, or covers it in flight, creating a smooth surface with low aerodynamic resistance.

[0008]It should be noted that, unlike the planing boats considered here, the fairing, according to the patents U.S. Pat. Nos. 3,614,032 and 6,042,052, should expose the step at relatively low speeds of the transitional takeoff mode and cover it in the main operational mode of flight at high speeds, whereas in the case of boats, on the contrary, the fairing should be used (be in the lower position and cover the transom step) at low speeds of the displacement mode and should be raised above the bottom trailing edge at the transom in the main high-speed mode of motion of the planing boat.

[0009]However, the practical application of such a design solution in relation to conventional planing boats encounters the following problem:

[0010]In order to reduce hydrodynamic resistance at low Froude numbers, the fairing in question must be given some kind of smoothly rising and tapering aftward contours behind the transom with sufficiently large radii of curvature. Otherwise, any steep formations of the fairing will lead to separation of flow and an increase in hydrodynamic resistance, making the use of such a fairing pointless.

[0011]The above circumstance results in a substantially large required fairing length, which significantly and sometimes unacceptably increases the longitudinal dimensions of the boat, creating operational problems associated, for example, with maneuvering in tight marinas and when mooring (not to mention the higher cost of maintaining a boat with such a long fairing in a marina, which cost usually depends on the length of the boat). It should be noted that the long fairing is not a problem in aviation applications due to typical long-tail aircraft configurations (including seaplanes).

[0012]Thus, long fairings behind the steps of seaplanes are quite acceptable since they do not increase their longitudinal dimensions, unlike boats, where similar bulky single-piece fairings would considerably increase length, resulting in operational inconveniences.

[0013]In the design of a retractable fairing for the transom of planing boat according to the patent U.S. Pat. No. 4,519,336, the upper forward part of the fairing is pivotally connected to the transom, so that it can be rotated about transverse horizontal axis from horizontal position (corresponding low speed mode of the boat and ensuring smooth low-drag flow at the stern) into the substantially vertical position (exposing the transom step for the planing mode) and arranged along the transom.

[0014]This technical solution really does significantly reduce the fairing's protrusion beyond and aft of the transom and boat's longitudinal dimensions in planing mode and at rest. However, given the actual fairing lengths required to ensure a smooth flow without flow disruption and, therefore, low resistance, the vertical dimensions of the fairing in the retracted position would be such that it would protrude above the deck of the vessel, creating inconvenience during operation (not to mention that such cluttering of the stern would hardly be acceptable, e.g., for fishing boats).

[0015]In addition, a long vertically raised fairing leads to a rise in the center of gravity of the boat and a decrease in the metacentric height, which negatively affects the transverse stability of the boat, while the additional inertial forces of a highly raised fairing increase the unfavorable outward roll when turning the boat at speed.

[0016]Moreover, the method of retracting the fairing following the patent U.S. Pat. No. 4,519,336 is unlikely to be suitable for boats and motor yachts with swim platforms. When analyzing the patent U.S. Pat. No. 4,519,336, it should also be noted that the patent's claims, stipulating the establishment of a “laminar water flow when said hollow body (i.e., fairing) is in its lowermost (i.e., operational) position”, are practically impossible to implement.

[0017]In real boats moving at speeds that make practical sense in the displacement mode (for which it makes sense to use such fairings), the flow at the transom (and, so, on the fairing) is always not laminar, but turbulent.

[0018]To illustrate this, as a rough example, consider a small boat with a displacement of 1 m 3 (35.3 cubic feet) and a waterline length of 5 m (16.4 feet) moving in the displacement mode at a speed of about 6 knots, which corresponds to a Froude number: Fr_D about 1. For such a boat, the laminar flow in the bow part of the wetted hull will be maintained up to approximately Reynolds numbers of 5.105, which correspond to a laminar flow length of about 0.16 m (6.3 inches), after which the flow becomes turbulent. That is, for this boat, the flow will be turbulent for the remaining and overwhelming 4.84 m (15.9 feet), i.e., 96.8% of the bottom length, so that it inevitably will be turbulent at the transom. Larger boats operating in the displacement mode at similar Froude numbers, and especially real boats with a less than perfectly smooth bottom surface, will have an even smaller length of the laminar flow in the bow part of the wetted hull than the above small boat, which makes it virtually impossible to achieve laminar flow at the transom, and thereby makes the claims of the patent U.S. Pat. No. 4,519,336 practically unrealizable. Theoretically, for the considered before 5 m (16.4 feet) boat with a perfectly smooth bottom, the laminar flow can reach the transom at Froude numbers no higher than 0.032, which sets the upper limit of applicability of the patent U.S. Pat. No. 4,519,336 and corresponds to the speed of the specified boat of less than 0.2 knots (about 4 inches per second). For larger and real bottom roughness boats this speed limit is much lower, of course, so operating boats at such negligible speeds loses practical meaning.

[0019]It should be mentioned that the prior art is represented also by many patents related to various devices and designs concerning the transom stern of planing boats, including all kinds of trim tabs, as well as movable and stationary extensions protruding from the stern, some of which are not intended and all of them do not solve the problem of ensuring a smooth, undisturbed flow optimal for the displacement mode, while keeping the planing mode unaffected. Among them, for example: U.S. Pat. Nos. 2,985,130; 3,019,755; 3,763,810; 5,224,436.

[0020]The last of those mentioned, for example, is a stationary, non-retractable extension protruding from the transom aftward and “located a tangible distance above the bottom surface of said hull”.

[0021]That is, this “hull extension” preserves the transom step and does not eliminate the flow disturbance associated with flow separation along the trailing edge of the bottom, which does not solve the problem of reducing resistance and improving the boat's efficiency when operating in the displacement mode. The reference in the patent to the reduction of resistance in the displacement mode due to an increase in the length (elongation) of the boat's hull is irrelevant in this case, since the well-known experimental data of the reference relate to hulls with continuous bottom surfaces (without steps).

[0022]More specifically, the experimental results of Clement and Blount, cited in the patent U.S. Pat. No. 5,224,436, indicate a reduction in hydrodynamic resistance at Froude numbers below about Fr_D=2.7 for planing hulls with higher elongation (i.e., higher length to width ratio) of continuous planing bottom surfaces.

[0023]In the design of patent U.S. Pat. No. 5,224,436, the original planing boat hull (to which the “hull extension” was attached “above the bottom surface”) remains the same and the elongation of the continuous bottom surfaces of this boat hull does not change, i.e., it remains the same both with and without the “hull extension”, which does not allow us to speak about the applicability of the experimental results of Clement and Blount.

[0024]Moreover, due to the low pressure zone (a kind of “suction”) formed under such “hull extension”, the resistance of the boat with the “hull extension” in the displacement mode will most likely be not lower, but higher than without the “hull extension”, which can only be somehow compensated for in the embodiments of the patent U.S. Pat. No. 5,224,436 that provide for the supply of air to the mentioned “suction” zone.

[0025]Thus, the claims of the patent U.S. Pat. No. 5,224,436 regarding the positive effect (reduced hydrodynamic resistance and increased hydrodynamic efficiency) provided by the patented “hull extension” are unsubstantiated.

[0026]Consequently, when examining the existing prior art in this field, one can find many examples of various devices and embodiments that somehow modify the transom step of planing boats.

[0027]However, none of the designs found in prior art provide a solution to the problem posed, which assumes the effective operation of planing boats at low Froude numbers without noted negative consequences for the main high-speed mode of motion and at rest.

[0028]The solution to the problem of excessive length of hydrodynamically efficient fairings provided by this invention is in keeping the properly long streamlined separation-free design of a retractable fairing, but capable of folding to compact dimensions in modes that do not require a smooth flow at the stern (beyond the displacement mode of motion), i.e., when the boat is moving in the main high-speed planing mode and at rest. In accordance with the present invention, this is achieved by making the fairing movable relative to the boat (enabling retractility similar to single-piece fairings), while consisting of at least two successive parts, the after of which can move relative the front one. Such design ensures, firstly, exposing (for efficient operation at high speeds) and covering the transom step (i.e., specifically, the trailing edge of planing bottom), providing a smooth separation-free flow at the trailing edge of the bottom and low hydrodynamic resistance in the displacement mode, and, secondly, foldability of the fairing, so that it can significantly reduce its length (as well as the length of the boat as a whole) in the inactive position (during planing and at rest), while keeping the proper smooth gently sloping surfaces of the fairing (being unfolded) not sacrificing the required length and, so, the efficiency and performance of the boat at low speeds. The above concept of this invention, which simultaneously solves the noted problems (being inherent in one-piece fairings) of operating the boat in both low-speed and high-speed modes, can be practically implemented in a number of design embodiments.

[0029]Among the examples of possible but not exclusive embodiments of the retractable and foldable fairing according to the present invention, the following can be given as regards foldability of the fairing:

[0030]1) As in all embodiments, the fairing consists of at least two parts (also referred to herein as sections or portions) arranged successively along the length of the boat aft of the transom step.

[0031]Since the hydrodynamically preferred configuration of the fairing presupposes tapering aftward, each successive, more aft part is assumed to be smaller than the preceding and adjacent more forward part. This after part can thus be pushed forward into the hollow, more forward part to be folded and stored there when the fairing is in its upper, inactive position, ultimately reducing the fairing length to the length of its front, i.e., most forward part adjacent to the transom.

[0032]Such a concept can be practically embodied, for example, by providing the more forward part with longitudinal rails attached from below to the upper surface of its shell, along which the after part of the fairing can slide or roll (if this rail track is equipped with rollers) forward until it stops, ensuring the complete placement of the after part inside the cavity of the hollow more forward part. To increase the extension length, each line of rails of the rail system can comprise a larger number (3, e.g.) of sliding or rolling pieces. Longitudinal movement along the rail track of the after part forward (to fold the fairing when it is in its upper inactive position) and backward (to unfold the fairing when it is deployed into its lower operational position) can be provided by a longitudinally arranged and centrally located electric linear actuator (ball screw drive), the front and rear ends of which are secured in the front and rear extremities of the more forward part of the fairing (attached from below to the upper surface of its shell, e.g.), and the ball nut of the drive is attached to the front end of the after part. In this case the rotation of the linear drive screw, provided by the electric motor, leads to the longitudinal movement of the ball nut, which pulls forward or pushes back the after part.

[0033]Similarly, with a larger number of fairing parts, they can also be folded telescopically, with each after part sliding forward into the cavity of the hollow, more forward part, which ultimately results in all the parts being collected and contained within the adjacent to the transom front part and thus reducing the length of the fairing to the length of the first, front part at the transom.

[0034]In this case, the after parts may or may not have a direct mechanical connection with more forward parts and the front part adjacent to the transom, and in the latter case, the movement of the after parts relative to more forward parts and the front part can be provided by a mechanism associated with the boat hull.

[0035]The fairing compactly packed in this way can be placed, for example, under a swim platform of boat or motor yacht, which arrangement doesn't increase and completely preserves the original dimensions of the boat in planing mode and at rest.

[0036]2) Assuming a fairing consisting of two parts successively arranged lengthwise behind the transom step, the adjacent upper rear extremity of the forward part and the upper front extremity of the after part can be pivotally connected, so that the after part can rotate relative to the forward part around a transverse horizontal axis.

[0037]Thus, in the case of the upper inactive position of the fairing (on plane and at rest), the after part can be rotated clockwise by 180 degrees when viewed from the starboard side of the boat using a hydraulic or electro-hydraulic actuator, or a worm gear driven by electric motor, and folded in its upside-down position over the forward part (thereby assuming a more forward position), which reduces the length of the fairing to the length of the forward part adjacent to the transom.

[0038]In the case of a hollow design of the forward part of the fairing, the after part of the fairing can rotate more than 180 degrees and fold into the cavity of the forward part.

[0046]If the movement of the after part(s) relative to the front part is provided by mechanism(s) associated with the boat hull and not connected to the front part (which is feasible in the folding method 1)), only the front adjacent to the transom part can be substantially vertically displaced. In this case, it is necessary to reserve a sufficient vertical distance between the front and next after part (in the forward folded position inside the front part) to ensure the required vertical movement of the front part.

[0049]The after part(s) not connected to the front part by folding mechanisms (which is feasible in the folding method 1)) in the folded state must be positioned in such a way so as not to interfere with the rotation of the front part.

[0050]If the front part is hinged to the hull (transom, e.g.) of the boat and the horizontal axis of rotation is located in the upper forward extremity of the front section of the fairing, this front section with the folded after parts in its cavity (method 1)), or, following method 2), with the hinged and turned after part being folded over the top of the front part (that is, the entire fairing in the folded form), can be rotated clockwise, when viewed from the starboard side, so as to rise above the trailing edge of the bottom (in projection onto the transverse plane).

[0051]Further on, the front part with the folded after part(s) can be rotated until the fairing contacts or fits against the transom surface.

[0052]In this case, unlike the design of patent U.S. Pat. No. 4,519,336, a boat with a compactly folded fairing will be free from the disadvantages of patent U.S. Pat. No. 4,519,336, i.e.:—the fairing will not protrude above the deck level, will not significantly increase the center of gravity and deteriorate transverse stability, will not create undesirable inertial heeling moments when the boat turns at speed, and may even be placed in a folded form under the swim platform.

[0053]Ultimately, unlike the design of U.S. Pat. No. 4,519,336, the folded fairing according to the present invention can be rotated even more clockwise, at an angle larger than the external angle of the transom to the horizon, in order to be placed and stored in a special recess in the transom, which makes the design of this invention even more compact and even more fully realizes the objectives of this invention. Such design of the fairing makes it possible to completely remove the fairing from the outside and put it into the boat hull, leaving no protruding parts, which ensures efficient operation in the main planing mode, does not clutter the stern (which is critical, for example, for fishing boats), does not affect much the position of the center of gravity and does not increase the dimensions of the boat at all, either at high speed or at rest.

[0056]In the parallelogram mechanism of each half, the inner, closer to the center plane hinged ends of the levers are fixed to the transom one above the other substantially vertically, and the outer hinged ends of the levers are fixed one above the other substantially vertically on the most forward part of this half of the fairing.

[0057]Being driven by vertically arranged and connected to one of the levers hydraulic or electrohydraulic actuators up, the parallelogram levers of the port side will rotate clockwise and the parallelogram levers of the starboard side will rotate counterclockwise, when viewed at the stern of the boat, and will turn from their lower position, where the levers were tilted downwards relative to the inner hinged ends mounted on the transom, to their upper position, where the levers are tilted upwards.

[0058]Said rotation of levers lifts the halves of the fairing from their lower operational position (corresponding to the displacement mode) and brings them to the upper inactive position above the trailing edges of the bottom planing surfaces of the boat's hull in projection onto the transverse plane, which will ensure effective operation of the boat in planing mode, while when folded, both of these halves of the fairing will protrude aft of the transom only by the length of the front part of the fairing providing compact configuration and convenient operation of the boat both at high speed and at rest.

[0059]In the case of using the transom fairing in accordance with the present invention on boats with swim platforms, the combination of foldability, which brings the fairing into a compact form, and retractability of such fairings, makes it possible to solve the problem of compatibility of low-speed fairings for planing boats with swim platforms (which is problematic for known designs of long and bulky one-piece fairings).

[0060]This applies in particular to the combination of the folding method 1) with the retracting methods a), c) and d), in which the fairing, folded up to the dimensions of the front part, can be pulled up to the level of the swim platform, or even partially enter from below into the bottom cavity of hollow swim platform, so that it will be completely within the dimensions of the swimming platform in the plan view, without cluttering or interfering with the use of the platform, and in no way increasing the dimensions of the boat.

[0061]In the case of using the foldable and retractable fairing according to the present invention on boats employing stern drives or outboard motors as their propulsion means, the part of said fairing adjacent to the transom is to be provided with recesses (in the form of wells, e.g.) for accommodating the stern drives or outboard motors.

[0062]The configuration and internal dimensions of such recesses must ensure steerability and trimability of the stern drives and outboard motors in all boat motion modes, which may require simultaneous coordination of the fairing's lifting to the upper position when trimming the stern drives and outboard motors to their upper inoperative position above the trailing edge of the bottom.

[0063]The sections of the foldable fairing can be made in the form of either hollow water-permeable thin-walled shells or volumetric structures having certain buoyancy.

[0064]In the latter case, the additional buoyancy of the fairing parts in displacement mode must be taken into account because it could affect the trim of the boat.

[0065]The water-permeable hollow thin-walled structures of the fairing do not have significant buoyancy and should not create noticeable problems with the boat's trim in the displacement mode. However, the water masses accumulated in the fairing cavity while floating, increase the boat's inertia and, so, can affect the boat's dynamics as well as its trim when getting on plane.

[0066]Although it should be noted in this connection that for some of the above mentioned embodiments, the considered accumulation of water should not present any particular problems due to the fact that the tilt of the fairing during its retraction should lead to the rapid removal of water from the cavities of the fairing parts.

[0067]At the same time, for some other embodiments (employing retracting methods a), c) and d), e.g.), in this regard, it is advisable to provide the bottom sections of the fairing with drainage holes or slots, in order to speed up the removal of water from the fairing cavity while underway and to neutralize the noted negative impact on the boat.

[0068]To increase the strength and rigidity of the fairing shells, they can be made three-layer with foam, balsa or honeycomb filler and (or) reinforced with internal frames and stringers. The structural designs of the aft sliding along part, as well as the front part in the case of the method 2) (which assumes the rotating aft part) , can include bulkheads.

[0069]As noted above, the entire range of operating speeds of a planing boat can be divided into three main sub-ranges characterized by specific balances of static and dynamic support forces and the corresponding nature of the boat's behavior on the water (resulting, in particular, in a characteristic vertical position and trim). These three sub-ranges are related to the corresponding ranges of relative speeds (Froude numbers) and include:—displacement mode (from rest to Fr_D of about 1), transitional mode (Fr_D between 1 and 3) and full planing mode (Fr_D about and greater than 3).

[0070]The embodiments of the foldable and retractable fairing according to this invention described here, make it possible, first of all, to reduce resistance and increase the efficiency of boat operation in a displacement mode of motion, in which static Archimedean forces dominate.

[0071]At the same time, in the transitional mode of motion, Archimedean forces continue to play a significant role in supporting the boat (along with the hydrodynamic lift generated by planing bottom, the share of which increases with increasing speed), due to which the fairing in question could provide a positive hydrodynamic effect well beyond Fr_D=1. A possible issue in this case may be that the transitional mode is usually accompanied by a significant increase in the trim of the boat, resulting in an increase in residual drag (manifested as a “hump” on the drag curve), whereas rounded fairing contours can potentially enhance this undesirable effect, increase somewhat the trim angle and thereby increase hydrodynamic drag at Froude numbers in excess of Fr_D=1.

[0072]Methods are known for moderating the excessive trim angle of planing boats in the transition mode by creating additional lifting force at the stern of the boat (using transom plates, e.g.), which leads to a moment leveling the position of the boat, reducing the trim and a corresponding decrease in resistance in the transition mode (which, in turn, facilitates and shortens the period of getting on plane). In the application to the fairing, similar method for eliminating this undesirable effect can be to bend the rearmost part of the fairing so that a concave surface is formed that would generate hydrodynamic lift and create a diving moment reducing the trim angle of the boat.

[0073]This solution, however, may lead to some increase in the length of the fairing and may deteriorate the flow at the rear of the fairing, and, thus, reduce the efficiency of the operation in displacement mode, which are the disadvantages of this design.

[0074]As an alternative solution, the fairing can be equipped with lateral longitudinal deflectors located near and slightly above the waterline in displacement mode.

[0075]Such deflectors do not increase the length of the fairing and do not have any effect on the flow around the fairing (which can be given an optimal shape) providing minimal resistance in the displacement mode. Whereas in the transitional mode, even at small trim angles, they begin to interact with the flow and generate hydrodynamic lift with corresponding diving moment, leveling the boat's position and thereby reducing resistance and increasing the hydrodynamic efficiency of the boat provided with the transom fairing in the transitional mode (Fr_D between 1 and 3). So that such combination of the transom fairing with said kind of deflectors potentially could ensure minimum drag and maximal hydrodynamic efficiency well over Fr_D=1.

[0076]To form such deflectors, the contours of the cross-sections of the fairing at the waterline should be bent outward so that at the outer edges of the contours (and, thus, the deflectors) they should be substantially horizontal (that is, the tangents to the contours of the cross-sections of the fairing at the lower outer edges of the deflectors should be substantially parallel to the horizon). In their simplified form, such deflectors can represent just flat horizontal surfaces (flat protrusions projecting outward) along the sides of the fairing at the level of (preferably slightly above) the waterline.

[0077]In the above embodiments, it is assumed that the control of the drive systems using hydraulic or electrohydraulic actuators, worm drives or electric linear actuators is preferably carried out from the boat control station (the instrument panel of the wheelhouse, steering console, etc.). At the same time it is supposed that for small boats, manual drive of the fairing folding and retracting mechanisms can also be used.

[0078]Summarizing the above, we can conclude that, to our best knowledge, the available information about the state of the art does not provide any proper solution to the combined problem of improving the efficiency of planing boats in displacement mode of motion without deteriorating their operability in the main planing mode and at rest, including the excessive increase in the dimensions of boats employing long single-piece fairings for the transom step, negative effect of vertically retracted fairing on the transverse stability of the boat, incompatibility of fairings with swim platforms, etc.

[0079]Accordingly, the object of this invention is to solve the problem of reducing resistance and increasing the efficiency of planing boats when sailing in displacement and partially transitional modes by using a retractable transom fairing, but avoiding deterioration of the boat's operational properties in its main high-speed mode of motion and at rest, which is achieved by means of special sectionalized foldable fairing designs, as a result of which the corresponding operational problems are eliminated.

SUMMARY OF THE INVENTION

[0080]The present invention provides a solution to the problem of reducing hydrodynamic resistance and increasing the efficiency of planing boats in the displacement (and partially transitional) mode of motion, without having a negative impact on the operation of the boats in the main high-speed mode at high Froude numbers and at rest, which is associated with the use of known bulky, long, single-piece designs of retractable fairings for transom steps of planing boats that excessively increase the dimensions of the boats and are incompatible with the swim platforms of the boats, create operational inconveniences in the vertical retracted position, clutter the stern, obstructing fishing from boats, deteriorate the static and dynamic transverse stability of the boats due to a higher position of the center of gravity and the effect of undesirable inertial moments during maneuvering in the main high-speed planing mode. According to this invention, the above-mentioned problems and shortcomings of retractable fairings for transom steps of planing boats are removed by using special designs of sectionalized foldable fairing consisting of at least two adjacent parts arranged, in the lower operational position of the fairing corresponding the displacement mode, successively lengthwise and aft of the transom, while the more aft of which is movable relative to the more forward one and thereby can be brought to a more forward position, which reduces the length of the fairing folded for boat operations beyond the displacement mode of motion, i.e., high-speed planing and rest, whereas to ensure hydrodynamically efficient operation of the boat in its principal planing mode, the trailing edges of the planing bottom of the boat must be released and exposed, for which the compactly folded fairing is to be retracted and positioned above the trailing edges.

[0081]The ability to fold the fairing to a compact size enables embodiments of this invention to solve the problems and eliminate the shortcomings of known long, bulky single-piece fairing designs for transoms of planing boats, so that the foldability of fairings following this invention results in compatibility with swim platforms, elimination of operational inconveniences associated with long single-piece fairings both at high-speed and at rest, decluttering the stern of the boat and making it convenient for fishing, elimination of the problem of the significant increase in the center of gravity created by long single-piece fairings retracted into vertical position, which negates the harmful effects of the long vertically retracted fairings on static and dynamic transverse stability, etc.

[0082]Various embodiments are disclosed herein for the method and apparatus related to the special designs of sectionalized foldable retractable fairings intended to reduce hydrodynamic resistance and increase the efficiency of planing boats in the displacement mode of motion, without having a negative impact on the operation of boats in the main high-speed planing mode at high Froude numbers and at rest.

[0083]In some embodiments, movable relatively the hull fairing as a whole, as well as each movable part of the fairing, are driven by hydraulic or electrohydraulic actuators, worm gears driven by electric motors, or electric linear actuators.

[0084]In some embodiments, all successively arranged parts of the fairing in its lower operational position form a smooth continuous surface gradually tapering rearwardly, so that in projection onto the transverse plane, each after part does not extend beyond the rear outer contour of each preceding and adjacent more forward part.

[0085]In some embodiments, the fairing comprises at least one pair of successively arranged and adjacent in the lower operational position of the fairing, forward part and after part, while the after part of the fairing is made movable relative to the hollow forward part and can be moved along forward into the cavity of the hollow forward part.

[0086]In some embodiments, the forward part of the fairing is provided with at least one longitudinal rail structurally connected to said forward part, along which rail the after part can slide or roll forward into the cavity of the hollow forward part, or backward to form the successive operational configuration of the fairing.

[0087]In some embodiments, sliding or rolling of the after part along the rail structurally connected to the forward part is carried out using at least one longitudinally arranged electric linear actuator, which front and rear ends are secured at the front and rear extremities of the forward part and a ball nut is attached to the front end of the after part, so that rotation of the linear drive screw, provided by electric motor, leads to the longitudinal movement of the ball nut, which pulls forward or pushes back the after part. In some embodiments, the boat is provided with at least one longitudinal rail structurally connected to the boat and arranged aft of boat's transom, along which rail the after part can slide or roll forward into the cavity of the hollow forward part, or backward to form the successive operational configuration of the fairing.

[0088]In some embodiments, sliding or rolling of the after part along the rail structurally connected to the boat is carried out using at least one longitudinally arranged electric linear actuator, which front end support is structurally connected to the boat at the transom, the rear end support is structurally connected to the boat further aft of the transom, and the ball nut is attached to the front end of the after part, so that rotation of the linear drive screw, provided by electric motor, leads to the longitudinal movement of the ball nut, which pulls forward or pushes back the after part.

[0089]In some embodiments, one pair of adjacent forward and after portions of the fairing are pivotally connected at the upper part of their adjacent extremities, so that the after portion can be rotated about the transverse horizontal axis and folded forward into an inverted position to be stored over the forward part.

[0090]In some embodiments, the most forward and adjacent to the transom part of the fairing is movable substantially vertically relatively the hull of the boat from the lower operational position to the upper inactive position.

[0091]In some embodiments, the upper extremity of the most forward and adjacent to the transom part of the fairing is pivotally connected to the hull and rotatable around an axis substantially normal to the vertical longitudinal center plane of the boat.

[0092]In some embodiments, said most forward part of the fairing is pivotally connected to the transom at the upper forward extremity of this part and can be rotated forward by an angle greater than the external angle of inclination of the transom to the horizon, to be retracted and stored in a transom recess.

[0093]In some embodiments, said most forward and adjacent to the transom part of the fairing is suspended on the transom by means of double-lever parallelogram mechanisms comprising levers and hinges with substantially normal to the center plane of the boat axes of rotation at the ends of these levers, so that turning the parallelogram levers brings said most forward part of the fairing either to its lower operational position, or to its upper inactive position.

[0094]In some embodiments, the fairing consists of two symmetrical relative the center plane and foldable halves, while each half comprises at least two successively arranged lengthwise parts and is suspended on the transom by means of at least one parallelogram mechanism with substantially longitudinal along the length of the boat axes of rotation, so that rotation of levers of the parallelogram mechanisms of halves in opposite directions lifts and retracts the halves from lower operational position to upper inactive position above the trailing edges of the bottom, and sequentially lowers them back to the lower operational position.

[0095]In some embodiments, shells of fairing are reinforced with frames and stringers.

[0096]In some embodiments, at least one of the hollow parts of the fairing is provided with drainage holes or slots.

[0097]In some embodiments, the forward part of the fairing adjacent to the transom is provided with at least one recess for accommodating a stern drive or outboard motor.

[0098]In some embodiments, the fairing is provided with lateral flow deflectors.

BRIEF DESCRIPTION OF THE DRAWINGS

[0099]The accompanying drawings, which are incorporated herein and constitute part of this specification, illustrate exemplary embodiments, and together with the general description given above and the detailed description given below, serve to explain the features of the various embodiments.

[0100]FIG. 1 depicts a schematic diagram illustrating the side elevation view of a planing boat floating on the surface of water, while submerged to its waterline corresponding to the stationary displacement state, and provided with a transom fairing according to some embodiments, wherein the fairing is shown unfolded, lowered and, so, deployed for operation in displacement mode.

[0101]FIG. 2 depicts a schematic diagram illustrating the side elevation view of a planing boat according to some embodiments, wherein the depicted boat represents basically the same boat as shown in FIG. 1, but with the fairing folded and retracted under the boat's swim platform for operation in the main high-speed planing mode and at rest.

[0102]FIG. 3 depicts a schematic diagram illustrating the stern view of a planing boat basically similar to the planing boat of the FIG. 1, floating on the surface of water, while submerged to its waterline corresponding to the stationary displacement state, and provided with a transom fairing according to some embodiments, wherein the fairing is shown unfolded, lowered and, so, deployed for operation in displacement mode.

[0103]FIG. 4 depicts a schematic diagram illustrating the stern view of a planing boat according to some embodiments, wherein the depicted boat represents basically the same boat as shown in FIG. 2 and features the fairing folded and retracted under boat's swim platform for operation in the main high-speed planing mode, or at rest.

[0104]FIG. 5 depicts a schematic diagram illustrating the side elevation view of the aft part of a planing boat, basically similar to boats shown in FIG. 1 and FIG. 3, provided with the transom fairing according to some embodiments, wherein the fairing, unfolded and lowered for operation in displacement mode, is shown in section along the center plane.

[0105]FIG. 6 depicts a schematic diagram illustrating the side elevation view of the aft part of a planing boat, basically similar to boats shown in FIG. 2 and FIG. 4, provided with the transom fairing according to some embodiments, wherein the fairing, folded and raised for operation in planing mode or for rest, is shown in section along the center plane.

[0106]FIG. 7 depicts a schematic diagram illustrating a top sectional view of the fairing, located at the aft part of a planing boat and corresponding to section 1-1 in FIG. 5, and shows the fairing unfolded for operation in displacement mode, while the upper panel of the shell of the front part of the fairing is not visible in this view, which makes it possible to display the device of the linear drive for retracting the after part of the fairing.

[0107]FIG. 8 depicts a schematic diagram illustrating a top sectional view of the fairing, located at the aft part of a planing boat and corresponding to section 2-2 in FIG. 6, and shows the fairing folded and raised for operation in planing mode or for rest, while the upper panel of the shell of the front part of the fairing is not visible in this view, which enables to display the device of the linear drive for retracting the aft part of the fairing.

[0108]FIG. 9 depicts a schematic diagram illustrating a view of the fairing, when viewed aft from the transom, corresponding to the view designated by the letters A-A in FIG. 5, in which the fairing is shown unfolded and lowered for operation in displacement mode.

[0109]FIG. 10 depicts a schematic diagram illustrating a cross-sectional view of the fairing corresponding to section 3-3 in FIG. 6, and shows the fairing being folded and raised for operation in planing mode or for rest.

[0110]FIG. 11 depicts a schematic diagram illustrating the side elevation view of the aft part of a planing boat, basically similar to boats shown in FIG. 1 and FIG. 3, provided with the transom fairing according to some embodiments, wherein the fairing, suspended on the transom by means of double-lever parallelogram mechanisms, is shown unfolded and lowered for operation in displacement mode.

[0111]FIG. 12 depicts a schematic diagram illustrating the side elevation view of the aft part of a planing boat, basically similar to boats shown in FIG. 2 and FIG. 4, provided with the transom fairing according to some embodiments, wherein the fairing, suspended on the transom by means of double-lever parallelogram mechanisms, is shown folded and raised into its inactive position ensuring effective operation of the boat in the main planing mode or staying at rest.

[0112]FIG. 13 depicts a schematic diagram illustrating a perspective aft bottom view of a boat provided with the transom fairing according to some embodiments, wherein the fairing is shown unfolded and positioned for operation in displacement mode.

[0113]FIG. 14 depicts a schematic diagram illustrating a perspective aft bottom view of a boat provided with the transom fairing according to some embodiments, wherein the depicted boat represents basically the same boat as shown in FIG. 13, but with the fairing folded and retracted for operation in the main high-speed planing mode, or at rest, when the boat is moored at a berth in a marina, for example.

[0114]FIG. 15 depicts a schematic diagram illustrating a perspective view of the transom fairing according to some embodiments, wherein the fairing, with its shells reinforced with internal frames and stringers, and the upper skin partially removed, is shown in the unfolded state corresponding operation in displacement mode.

[0115]FIG. 16 depicts a schematic diagram illustrating the side elevation view of the aft part of a planing boat provided with a transom recess and a fairing foldable into this recess according to some embodiments, wherein the fairing is pivotally connected to the transom and is shown unfolded and lowered for operation in displacement mode.

[0116]FIG. 17 depicts a schematic diagram illustrating the side elevation view of the aft part of a planing boat provided with the transom recess and the transom fairing according to some embodiments and basically corresponding to the embodiment shown in FIG. 16, wherein the fairing is pivotally connected to the transom, but is shown folded and completely retracted into the transom recess, so that the boat is to be suitable for operation in planing mode or be at rest.

[0117]FIG. 18 depicts a schematic diagram illustrating the side elevation view of the aft part of a planing boat provided with the transom fairing suspended on the transom by means of double-lever parallelogram mechanisms according to some embodiments, wherein the fairing portions are pivotally connected and shown unfolded and lowered for operation in displacement mode.

[0118]FIG. 19 depicts a schematic diagram illustrating the side elevation view of the aft part of a planing boat, basically similar to the boat shown in FIG. 18, provided with the transom fairing according to some embodiments, wherein the fairing portions are pivotally connected, while the fairing, suspended on the transom by means of double-lever parallelogram mechanisms, is shown folded and raised into its inactive position ensuring effective operation of the boat in the main planing mode or staying at rest.

[0119]FIG. 20 depicts a schematic diagram illustrating the stern view of a boat according to some embodiments, wherein the boat is provided with a foldable transom fairing, comprising pivotally connected parts, shown unfolded in its lower operational position, corresponding to displacement mode, and consisting of two symmetrical relative to the center plane halves, each suspended on the transom by means of a parallelogram mechanism with longitudinal axes of rotation of levers.

[0120]FIG. 21 depicts a schematic diagram illustrating the stern view of a boat according to some embodiments, wherein the boat is operated in its main high-speed planing mode or is at rest, and is provided with a foldable transom fairing consisting of two halves symmetrical relative to the center plane, shown in their upper inactive position, while each half of the fairing is suspended on the transom by means of a parallelogram mechanism with longitudinal axes of rotation of the levers and comprises pivotally connected parts, shown with the after part folded over the front part.

[0121]FIG. 22 depicts a schematic diagram illustrating the aft view of a fairing according to some embodiments, wherein the fairing, unfolded and deployed for operation in displacement and transitional modes, is provided with lateral flow deflectors.

[0122]FIG. 23 depicts a schematic diagram illustrating a perspective aft bottom view of a boat provided with the transom fairing according to some embodiments, wherein the fairing is shown unfolded and positioned for operation in displacement and transitional modes, and provided with lateral flow deflectors.

[0123]FIG. 24 depicts a schematic diagram illustrating the side elevation view of the aft part of a planing boat, provided with the transom fairing according to some embodiments, wherein the fairing, unfolded and lowered for operation in displacement mode, is shown in section along the center plane, while the front part of the fairing is suspended on the transom by means of parallelogram mechanisms and the after part of fairing can slide forward along rails structurally connected to boat's swim platform.

[0124]FIG. 25 depicts a schematic diagram illustrating the side elevation view of the aft part of a planing boat provided with the transom fairing according to some embodiments, wherein the fairing, folded and lifted for operation in planing mode or for rest by means of raising the front part of the fairing by parallelogram mechanisms and sliding the after part forward along rails structurally connected to boat's swim platform, is shown in section along the center plane.

DETAILED DESCRIPTION OF THE INVENTION

[0125]Various embodiments will be described in detail with reference to the accompanying drawings. Wherever possible, the same reference will be used throughout the drawings to refer to the same or like parts. References made to particular examples and implementations are for illustrative purposes, and are not intended to limit the scope of the claims.

[0126]FIG. 1 depicts a schematic diagram illustrating the side elevation view of a planing boat floating on the surface of water, while submerged to its waterline corresponding to the stationary displacement state and provided with a transom fairing according to some embodiments, wherein the fairing is shown unfolded, lowered and, so, deployed for operation in displacement mode.

[0127]As features characterizing the boat 101 as a planing boat, the boat 101 has a substantially vertical transom 102, defining by the intersection of its transverse plane with the sides 103 and bottom 104 the peripheral edge of the transom, which comprises substantially vertical edges 105 formed by the intersection of transom 102 with the sides 103 and extending upward from the chines 106, and the trailing edges 107 of the planing bottom surfaces 104, located between the chines 106 and the keel line 108.

[0128]The boat 101 is provided with a movable relative the hull of the boat 101, located aft of transom 102 and foldable fairing, shown in its unfolded lower operational position, corresponding low-speed displacement mode of the boat 101, and consisting of two successively arranged along the length of the boat 101 portions:—a hollow front part 109 and an after part 110, movable relatively to the front part 109, wherein part 109 and part 110 are in contact along a longitudinal cylindrical surface corresponding to contour 111, while the hollow front part 109 has a peripheral leading edge 112, which peripheral leading edge 112 is shaped to conform to, abuts upon and fits flush with the lower portion of the peripheral edge of the transom 102 including the trailing edges 107 and substantially vertical edges 105 up to a level somewhat above the waterline “WL”.

[0129]The fairing, represented in the shown operational position by successively composed front part 109 and after part 110, is assumed to have a smooth continuous surface and a configuration tapering from the transom 102 further aft both in the plan view and, as shown in this side elevation view, with contours rising gradually from the trailing edges 107 of the bottom to the waterline “WL”. Such a streamlined shape of the fairing, providing a smooth transition from the angular shape of the lower aft section of the planing boat 101, formed by the dihedral bottom 104, flat planes of the sides 103 and the transverse transom plane 102, to the rounded stern formations, optimal for displacement vessels sailing at low Froude numbers, ensures a smooth and separation-free flow around the stern of the boat 101 and results in low hydrodynamic resistance in displacement mode (meaning higher hydrodynamic efficiency), which leads to a decrease in the power required to propel the boat 101, a decrease in fuel consumption and a corresponding increase in cruising range when sailing in the displacement mode. The indicated tapering aftward shape of the fairing suggests that, in projection onto the transverse plane, the after part 110 does not extend beyond the boundaries of the contour 111, and, so, can be moved forward into the cavity of the hollow front part 109. The hull of the boat 101 is also equipped with a swim platform 113, mounted on the transom 102, extending aftward of the transom 102 and above the waterline “WL”, so that the substantially horizontal upper edge of the fairing 114 is located below the platform 113 and above the waterline “WL”. Thus, the fairing can be folded lengthwise to the length of the front part 109 and moved up to the platform 113 to be completely covered by the platform 113 in the plan view, while exposing the tailing edges 107.

[0130]FIG. 2 depicts a schematic diagram illustrating the side elevation view of a planing boat according to some embodiments, wherein the depicted boat represents basically the same boat as shown in FIG. 1, but with the fairing folded and retracted under boat's swim platform for operation in the main high-speed planing mode and at rest.

[0131]In FIG. 2 the planing boat 101 with its transom 102, sides 103, planing bottom surfaces 104, chines 106, the keel line 108 and the peripheral edge of the transom, comprising substantially vertical edges 105, formed by intersection of the surface of transom 102 with sides 103, and the trailing edges 107 of the planing bottom surfaces 104, formed by intersection of the transom 102 with said bottom surfaces 104, and connecting the aftermost points of the keel line 108 and chines 106, is assumed to be moving in planing mode, which mode requires exposure of the trailing edges 107, or staying at rest.

[0132]The boat 101 is also equipped with a swim platform 113, mounted on the transom 102, extending aft of the transom 102.

[0133]As in FIG. 1, the boat 101 is provided with the foldable and retractable fairing, movable relative the hull of the boat 101, located aft of transom 102, featuring a tapering configuration further aft from the transom 102 and comprising two parts, which fairing is shown in its folded and retracted position, corresponding the planing mode or the rest, and, so, represented here by the only visible in this position hollow front part 109 with its peripheral leading edge 112 and the rear outer contour 111.

[0134]Just as it was noted in relation to FIG. 1, because of the rearwardly tapering configuration of the fairing, the after part of the fairing does not extend beyond the boundaries of the contour 111 in projection onto the transverse plain, and, so, when moved forward, the after part can be folded and placed inside the hollow front part 109. Thus, in the FIG. 2 it is assumed that the after part is pushed into the cavity of the hollow front part 109 and is completely accommodated there in its folded position, which reduces the length of the fairing to the length of its front part 109, while the swim platform 113 completely covers the front part of the fairing 109 in the plan view.

[0135]In order to provide efficient, low-drag motion of the boat 101 in its primary high-speed planing mode, the hydrodynamic lift-generating flow of water along the bottom 104 must be separated at the trailing edge 107, for which purpose the trailing edge 107 must be uncovered by means of a transom step 201 formed by the exposed surface of the transom 102 extending substantially vertically from the trailing edge 107.

[0136]This is achieved by raising the folded fairing, i.e. raising the front hollow part 109 adjacent to the transom 102 with the after part folded inside, from the lower operational position of the front part 109 (covering from behind the trailing edge 107 in the displacement mode) to the position somewhat above the edge 107, as shown in the FIG. 2, which exposes the edge 107 and forms the transom step 201 extending from the trailing edge 107 up to the peripheral leading edge 112 of the front part 109.

[0137]In the depicted configuration of FIG. 2, where the boat 101 is equipped with a swim platform 113, the fairing represented by the front part 109 can be raised until its upper edge 114 touches the lower part of the platform 113.

[0138]By means of this, considering that in this embodiment the swim platform 113 totally covers the front part 109 of the fairing in the plan view, the compactly folded fairing is entirely placed under the swim platform 113, which makes this design completely compatible with the swim platform 113, does not increase the dimensions of the boat 101 in any way and practically does not elevate the center of gravity of the boat 101 in any significant way.

[0139]Thus, this embodiment of foldable retractable transom fairing in accordance with the present invention eliminates the disadvantages of bulky single-piece fairings and completely solves the problems of using low-speed fairings on planing boats, providing low hydrodynamic resistance in the displacement mode of motion (i.e., increasing hydrodynamic efficiency), resulting in low power and fuel consumption, and a corresponding increase in the cruising range (i.e., improving the operational properties of boats), without creating inconveniences during operation in the main high-speed planing mode and at rest, without increasing the dimensions of the boats and without cluttering the stern, while being compatible with swim platforms, without having a significant effect on the position of the center of gravity and thereby not deteriorating the static and dynamic stability.

[0140]It is assumed that all the above operations for folding and retracting the fairing are carried out using (not shown) mechanisms employing hydraulic or electrohydraulic actuators, or electric linear actuators.

[0141]FIG. 3 depicts a schematic diagram illustrating a stern view of a planing boat basically similar to the planing boat of the FIG. 1, floating on the surface of water, while submerged to its waterline corresponding to the stationary displacement state, and provided with a transom fairing according to some embodiments, wherein the fairing is shown unfolded, lowered and, so, deployed for operation in displacement mode.

[0142]As in FIG. 1, the planing boat 101 floats on the surface of water while submerged to its waterline “WL” corresponding to the stationary displacement state, and features a substantially vertical transom 102, the lower peripheral edge of which is covered and not visible here, sides 103 and a swim platform 113, mounted on the transom 102 and extending aftward of the transom 102 above the waterline “WL”.

[0143]The boat 101 is provided with a movable relative the hull of the boat 101, located aft of transom 102 and foldable fairing, shown in its unfolded lower operational position, corresponding low-speed displacement mode of the boat 101, and consisting of two successively arranged along the length of the boat 101 portions:—the hollow front part 109 and the after part 110, which are in contact along the contour 111. The hollow front part 109 has a peripheral leading edge 112, which is shaped to conform to, abuts upon and is flush with the lower peripheral edge of the transom 102 up to the level of substantially horizontal upper edge of the fairing 114 located somewhat below the platform 113 and above the waterline “WL”.

[0144]It is assumed that the platform 113 partially covers the fairing in the plan view, while completely covering the front part 109.

[0145]The fairing, represented in the shown operational position by successively composed front part 109 and after part 110, is assumed to have a smooth continuous surface and a configuration tapering from the transom 102 further aft both in the plan view and with contours rising gradually from the peripheral leading edge 112 to the waterline “WL”, which optimal for displacement vessels sailing at low Froude numbers shape ensures a smooth and separation-free flow around the stern of the boat 101 and results in low hydrodynamic resistance in displacement mode (meaning higher hydrodynamic efficiency), which leads to a decrease in the power required to propel the boat 101, a decrease in fuel consumption and a corresponding increase in cruising range when sailing in the displacement mode.

[0146]FIG. 4 depicts a schematic diagram illustrating the stern view of a planing boat according to some embodiments, wherein the depicted boat represents basically the same boat as shown in FIG. 2 and features the fairing folded and retracted under boat's swim platform for operation in the main high-speed planing mode, or rest.

[0147]In this diagram the planing boat 101 with its transom 102, sides 103, chines 106, the keel line 108, the swim platform 113, mounted on the transom 102 and extending aftward of the transom 102, and the lower peripheral edge of the transom, comprising substantially vertical edges 105, formed by intersection of the transom 102 with sides 103, and the trailing edges 107 of the planing bottom surfaces connecting the aftermost points of the keel line 108 and chines 106, is assumed to be moving in planing mode, which mode requires exposure of the trailing edges 107, or staying at rest.

[0148]As in FIG. 2, the boat 101 is provided with the foldable and retractable fairing shown in its folded and retracted position, corresponding to the planing mode or the rest, which folded fairing locates aft of transom 102 and comprises the hollow front part 109 with its peripheral leading edge 112 and the rear outer contour 111, and the after part 110.

[0149]Because of the rearwardly tapering configuration of the fairing, the entire after part 110 of the fairing does not extend beyond the boundaries of the contour 111 in projection onto the transverse plain, and, so, when moved forward, the after part can be placed and folded inside the hollow front part 109.

[0150]Thus, in the FIG. 4 it is assumed that the after part 110 is pushed forward into the cavity of the hollow front part 109 and is completely accommodated there in its folded position, which reduces the length of the fairing to the length of its front part 109.

[0151]In order to provide efficient, low-drag motion of the boat 101 in its primary high-speed planing mode, the flow of water along the bottom of the planing boat 101 must be separated at the trailing edge 107, for which purpose the trailing edge 107 must be uncovered by means of a transom step 201 formed by the exposed surface of the transom 102 extending substantially vertically from the trailing edge 107.

[0152]This is achieved by raising the folded fairing, i.e. raising the front hollow part 109 adjacent to the transom 102 with the after part 110 folded inside, from the lower operational position of the front part 109 (covering from behind the trailing edge 107 in the displacement mode) to the position somewhat above the edge 107, as shown in the FIG. 4, which exposes the edge 107 and forms the transom step 201 extending from the trailing edge 107 up to the peripheral leading edge 112 of the front part 109.

[0153]In the depicted embodiment of FIG. 4, wherein the boat 101 is equipped with a swim platform 113, which presumably does not have a cavity in its bottom part, where the upper part of the fairing could fit, the fairing is raised up to the position where its upper edge 114 touches the lower part of the platform 113.

[0154]By means of this, considering that in this embodiment the swim platform 113 totally covers the front part 109 of the fairing in the plan view, the compactly folded fairing is completely placed under the swim platform 113, which makes this design perfectly compatible with the swim platform 113, does not increase the dimensions of the boat 101 in any way and practically does not elevate the center of gravity of the boat 101 in any significant way.

[0155]FIG. 5 depicts a schematic diagram illustrating the side elevation view of the aft part of a planing boat, basically similar to boats shown in FIG. 1 and FIG. 3, provided with the transom fairing according to some embodiments, wherein the fairing, unfolded and lowered for operation in displacement mode, is shown in section along the center plane. In the broken-away stern portion of the hull of the boat shown in the FIG. 5, the planing boat 101 with its substantially vertical transom plane 102, sides 103, planing bottom surfaces 104, chines 106, substantially vertical edges 105 formed by the intersection of transom 102 with the sides 103 and extending upward from the chines 106, the keel line 108 and the trailing edges 107 of the planing bottom surfaces 104, which edges 107 connect the keel line 108 and the chines 106 at their aftermost points, is assumed to be floating on the surface of the water, while submerged to its waterline “WL” corresponding to the stationary displacement state.

[0156]The boat 101 is provided with a movable relative the hull of the boat 101, located aft of transom 102 and foldable fairing, which center plane section is shown in unfolded lower operational position, corresponding low-speed displacement mode of the boat 101.

[0157]The fairing, which shells, in order to not clutter the view of its foldable and retractable design, are shown in the embodiment not reinforced with internal frames and stringers, comprises two successively arranged along the length of the boat 101 portions:—the hollow front part 109 and the after part 110 (the sections of their shells by the center plane are hatched), which are in contact along a longitudinal cylindrical surface corresponding to contour 111, representing the peripheral contour of the rear edge of the front part 109, while the hollow front part 109 has a peripheral leading edge 112, which peripheral leading edge 112 is shaped to conform to, abuts upon and fits flush with the lower peripheral edge of the transom 102 including the trailing edges 107 and substantially vertical edges 105 up to a level somewhat above the waterline “WL”.

[0158]The fairing, represented in the shown operational position by successively composed front part 109 and after part 110, is assumed to have a smooth continuous surface and a configuration tapering from the transom 102 further aft both in the plan view and, as shown in this side elevation view, with contours rising gradually from the trailing edges 107 of the bottom to the waterline “WL”. Such a streamlined shape of the fairing, providing a smooth transition from the angular shape of the lower aft section of the planing boat 101, formed by the dihedral bottom 104, flat planes of the sides 103 and the transverse transom plane 102, to the rounded stern formations, optimal for displacement vessels sailing at low Froude numbers, ensures a smooth and separation-free flow around the stern of the boat 101 and results in low hydrodynamic resistance in displacement mode (meaning higher hydrodynamic efficiency), which leads to a decrease in the power required to propel the boat 101, a decrease in fuel consumption and a corresponding increase in cruising range when sailing in the displacement mode. At the same time, the indicated tapering aftward shape of the fairing suggests that the after part 110 does not extend beyond the boundaries of said longitudinal cylindrical surface corresponding to the contour 111, and thus the after part 110 can be moved (e.g., shifted lengthwise) forward for folding and storage inside the hollow front part 109. For this purpose the front part 109 is provided with longitudinal inverted T-shaped rails 501 attached from below to the upper skin panel 502 of the shell of the hollow front part 109, along which inverted T-slot sliders 503 of the after part 110 can slide forward until the after part 110 should stop in its extreme forward position, ensuring the complete placement of the after part 110 inside the cavity of the hollow front part 109.

[0159]To perform such folding, the fairing is equipped with a longitudinally arranged and centrally located electric linear actuator, which provides longitudinal movement of the rear part 110 and comprises the linear drive screw 504, supported by the front end support 505 (combined with drive) and rear end support 506, secured from below to the upper skin panel 502 in the front and rear extremities of the front part 109, respectively, and the ball nut 507 of the drive attached to the front end of the after part 110 by brackets (not shown), which ball nut 507, in the shown operational position of completely unfolded fairing, is brought along the linear drive screw 504 to the rearmost position of the linear actuator.

[0160]The rotation of the linear drive screw 504, provided by the electric motor 508 through the drive of the front end support 505, leads to the longitudinal movement of the ball nut 507, which pulls forward or pushes back the after part 110.

[0161]The hull of the boat 101 is also equipped with a swim platform 113, mounted on the transom 102, extending aftward of the transom 102 and above the waterline “WL”, so that in this mode the substantially horizontal upper edge of the fairing 114 is located somewhat below the platform 113 and above the waterline “WL”, and the platform 113 partially covers the fairing in the plan view, while completely covering the front part 109. In the embodiment shown in the FIG. 5, the fairing (specifically its front part 109) is suspended from below the swim platform 113 by means of vertical hydraulic actuators 509 shown in the conventional breakout 510 of the side part of the swim platform 113.

[0162]Retraction of hydraulic actuators 509, arranged assumably in pairs on both sides of the front part 109, leads to vertical lifting of the fairing (i.e. its front part 109 with the after part 110 folded inside) and its transfer to the upper inactive position, which ensures efficient operation of the boat in planing mode and minimal dimensions when at rest.

[0163]To ensure a tight fit of the peripheral leading edge 112 of the front part 109 to the transom 102, the edge 112 and the plane of the transom 102 can be provided with vertical rail slides (not shown), which would hold the front part 109 in constant contact with the transom 102 during lifting and lowering of the fairing.

[0164]The numbers 1-1 in FIG. 5 indicate the section of the fairing by a horizontal plane.

[0165]The letters A-A designate the view of fairing rearwards from the transom 102.

[0166]FIG. 6 depicts a schematic diagram illustrating the side elevation view of the aft part of a planing boat, basically similar to boats shown in FIG. 2 and FIG. 4, provided with the transom fairing according to some embodiments, wherein the fairing, folded and raised for operation in planing mode or for rest, is shown in section along the center plane.

[0167]In the broken-away stern portion of the hull of the boat shown in the FIG. 6, the planing boat 101 with its substantially vertical transom plane 102, sides 103, planing bottom surfaces 104, chines 106, substantially vertical edges 105 formed by the intersection of transom 102 with the sides 103 and extending upward from the chines 106, the keel line 108 and the trailing edges 107 of the planing bottom surfaces 104, which edges 107 connect the keel line 108 and the chines 106 at their aftermost points, is assumed to be moving in its main high-speed planing mode or staying at rest.

[0168]The boat 101 is provided with a movable relative the hull of the boat 101, located aft of transom 102 and foldable fairing, which center plane section is shown in the folded upper inactive position. The fairing, which shells, in order to not clutter the view of its foldable and retractable design, are shown in the embodiment not reinforced with internal frames and stringers, comprises the hollow front part 109 with its peripheral rear edge 111, the peripheral leading edge 112 adjacent to the transom 102 and the upper edge 114, and the after part 110 not extending beyond the contour of the peripheral rear edge 111 in projection onto the transverse plane, which enabled to move the after part 110 forward and fold it inside the cavity of the hollow front part 109 (the sections of their shells by the center plane are hatched), so that the fairing is shown in the folded state. For the purpose of moving along and folding the after part 110 (i.e., folding the fairing), the after part 110 is provided with inverted T-slot sliders 503, which slid forward along longitudinal inverted T-shaped rails attached from below to the upper skin panel 502 of the shell of the hollow front part 109, until the after part 110 stopped in the shown extreme forward position, ensuring the complete placement of the after part 110 inside the cavity of the hollow front part 109.

[0169]To perform such folding, the fairing is equipped with a longitudinally arranged and centrally located electric linear actuator, which provides longitudinal movement of the rear part 110 and comprises the linear drive screw 504, supported by the front end support 505 (combined with drive) and rear end support 506, secured from below to the upper skin panel 502 in the front and rear extremities of the front part 109, respectively, and the ball nut 507 of the drive attached to the front end of the after part 110 by brackets (not shown), which ball nut 507 in the shown inactive position of the folded fairing, is brought along the linear drive screw 504 to the most forward position of the linear actuator. The rotation of the linear drive screw 504, provided by the electric motor 508 through the drive of the front end support 505, leads to the longitudinal movement of the ball nut 507, which pulls forward or pushes back the after part 110.

[0170]In order to provide efficient, low-drag motion of the boat 101 in its primary high-speed planing mode, the flow of water along the planing bottom of the boat 101 must be separated at the trailing edges 107, for which purpose the trailing edges 107 must be uncovered by means of a transom step 201 formed by the exposed surface of the transom 102 extending substantially vertically from the trailing edges 107.

[0171]This is achieved by raising the folded fairing, i.e. raising the front hollow part 109 adjacent to the transom 102 with the after part 110 folded inside, from the lower operational position of the front part 109 (covering from behind the trailing edges 107 in the displacement mode) to the position somewhat above the edges 107, as shown in the FIG. 6, which exposes the edges 107 and forms the transom step 201 extending from the trailing edges 107 up to the peripheral leading edge 112 of the front part 109.

[0172]In the depicted embodiment of FIG. 6, wherein the boat 101 is equipped with a swim platform 113 completely covering the front part 109 in the plan view, the fairing is raised up to the position where its upper edge 114 touches the lower part of the platform 113, so that the compactly folded fairing is completely placed under the swim platform 113, which makes this design perfectly compatible with the swim platform 113, does not increase the dimensions of the boat 101 in any way and practically does not elevate the center of gravity of the boat 101 in any significant way.

[0173]In the embodiment shown in the FIG. 6, the fairing (specifically its front part 109) is suspended from below the swim platform 113 by means of vertical hydraulic actuators 509 shown in the conventional breakout 510 of the side part of the swim platform 113. Retraction of actuators 509, arranged assumably in pairs on both sides of the front part 109, has resulted in vertical lifting of the fairing (i.e. its front part 109 with the after part 110 folded inside) and its transfer to the upper inactive position, which ensures efficient operation of the boat in planing mode and minimal dimensions when at rest.

[0174]To ensure a tight fit of the peripheral leading edge 112 of the front part 109 to the transom 102, the edge 112 and the plane of the transom 102 can be provided with vertical rail slides (not shown), which would hold the front part 109 in constant contact with the transom 102 during lifting and lowering of the fairing.

[0175]The numbers 2-2 in FIG. 6 indicate the section of the fairing by a horizontal plane.

[0176]The numbers 3-3 in FIG. 6 indicate the section of the fairing by a vertical plane.

[0177]FIG. 7 depicts a schematic diagram illustrating a top sectional view of the fairing, located at the aft part of a planing boat and corresponding to section 1-1 in FIG. 5, and shows the fairing unfolded for operation in displacement mode, while the upper skin panel of the shell of the front part of the fairing is not visible in this view, which makes it possible to display the device of the linear drive for retracting the after part of the fairing. In the broken-away stern portion of the hull of the boat depicted in the FIG. 7, the planing boat 101 with its transom 102 and sides 103, shown conditionally as a horizontal cut in the plan view, is provided with a movable relative the hull of the boat 101, located aft of transom 102 and foldable fairing comprising two successively arranged along the length of the boat 101 portions:—the hollow front part 109 and the after part 110, which are in contact along a longitudinal cylindrical surface corresponding to contour 111, representing the peripheral contour of the rear edge of the front part 109, while in the assumed displacement mode the hollow front part 109 has a peripheral leading edge 112 shaped to conform to, to abut upon and be flush with the lower peripheral edge of the transom 102.

[0178]The tapering aftward shape of the fairing suggests that the after part 110 does not extend beyond the boundaries of said longitudinal cylindrical surface corresponding to the contour 111, and thus the after part 110 can be moved (e.g., shifted) forward for folding and storage inside the hollow front part 109. For this purpose the front part 109 is provided with longitudinal inverted T-shaped rails 501 (the sections of their struts by the horizontal plane are hatched) attached from below to the upper skin panel (not visible in this sectional view) of the shell of the hollow front part 109, along which rails inverted T-slot sliders 503 of the after part 110 can slide forward until the after part 110 should stop in its extreme forward position, ensuring the complete placement of the after part 110 inside the cavity of the hollow front part 109.

[0179]To perform such folding, the fairing is equipped with a longitudinally arranged and centrally located electric linear actuator, which provides longitudinal movement of the rear part 110 and comprises the linear drive screw 504, supported by the front end support 505 (combined with drive) and rear end support 506, secured from below to the upper skin panel (not visible in this sectional view) in the front and rear extremities of the front part 109, respectively, and the ball nut 507 of the drive attached by brackets 701 to the front end of the after part 110 (and more specifically to the forward part of the inverted T-slot sliders 503 of the after part 110), which ball nut 507 in the shown operational position of the completely unfolded fairing, is brought along the linear drive screw 504 to the rearmost position of the linear actuator. The rotation of the linear drive screw 504, provided by the electric motor 508 through the drive of the front end support 505, leads to the longitudinal movement of the ball nut 507, which pulls forward or pushes back the brackets 701 as well as the after part 110 as a whole.

[0180]It is supposed that in the embodiment of the FIG. 7, the fairing (specifically its front part 109) is suspended from below the swim platform of the boat 101 by means of four vertical hydraulic actuators 509 conditionally shown by their shaded cross sections.

[0181]The retraction of hydraulic actuators 509, arranged in pairs on both sides of the front part 109, should lift the fairing (i.e. its front part 109 with the after part 110 folded inside) and transfer it to the upper inactive position, which ensures efficient operation of the boat in planing mode and (if folded) compact dimensions at high speed and at rest.

[0182]To ensure a tight fit of the peripheral leading edge 112 of the front part 109 to the transom 102, the edge 112 and the plane of the transom 102 can be provided with vertical rail slides (not shown), which would hold the front part 109 in constant contact with the transom 102 during lifting and lowering of the fairing.

[0183]FIG. 8 depicts a schematic diagram illustrating a top sectional view of the fairing, located at the aft part of a planing boat and corresponding to section 2-2 in FIG. 6, and shows the fairing folded and raised for operation in planing mode or for rest, while the upper panel of the shell of the front part of the fairing is not visible in this view, which enables to display the device of the linear drive for retracting the aft part of the fairing.

[0184]In the broken-away stern portion of the hull of the boat depicted in the FIG. 7, the planing boat 101 with its transom 102 and sides 103, shown conditionally as a horizontal cut in the plan view, is provided with a movable relative the hull of the boat 101, located aft of transom 102 and foldable fairing comprising the hollow front part 109 with its rear 111 and leading 112 peripheral edges, and the after part 110.

[0185]Due to the shape of the fairing tapering aftward in the operational unfolded state, the after part 110 does not extend beyond the boundaries of the contour 111 in the projection onto the transverse plane, which made it possible to move the after part 110 forward, fold it and store it inside the hollow front part 109.

[0186]For this purpose the front part 109 is provided with longitudinal inverted T-shaped rails 501 (the sections of their struts are hatched) attached from below to the upper skin panel (conditionally removed in this sectional view) of the shell of the hollow front part 109, along which rails the inverted T-slot sliders 503 of the after part 110 slid forward until the after part 110 stopped in the shown extreme forward position, ensuring the complete placement of the after part 110 inside the cavity of the hollow front part 109.

[0187]To accomplish such folding, the fairing is equipped with a longitudinally arranged and centrally located electric linear actuator, which provides longitudinal movement of the rear part 110 and comprises the linear drive screw 504, supported by the front end support 505 (combined with drive) and rear end support 506, secured from below to the upper skin panel (conditionally removed in this sectional view) in the front and rear extremities of the front part 109, respectively, and the ball nut 507 of the drive attached by brackets 701 to the front end of the after part 110 (and more specifically to the forward part of the inverted T-slot sliders 503 of the after part 110), which ball nut 507 is shown brought along the linear drive screw 504 to the most forward position of the linear actuator, corresponding completely folded inactive position of the fairing. The rotation of the linear drive screw 504, provided by the electric motor 508 through the drive of the front end support 505, leads to the longitudinal movement of the ball nut 507, which pulls forward or pushes back the brackets 701 as well as the after part 110 as a whole.

[0188]It is supposed that in the embodiment of the FIG. 8, the fairing (specifically its front part 109) is suspended from below the swim platform of the boat 101 by means of four vertical hydraulic actuators 509 conditionally shown by their cross sections.

[0189]The retraction of hydraulic actuators 509, arranged in pairs on both sides of the front part 109, has raised the fairing (i.e. its front part 109 with the after part 110 folded inside) and transferred it to the upper inactive position, which ensures efficient operation of the boat in planing mode and compact dimensions when at high speed and at rest.

[0190]To ensure a tight fit of the peripheral leading edge 112 of the front part 109 to the transom 102, the edge 112 and the plane of the transom 102 can be provided with vertical rail slides (not shown), which would hold the front part 109 in constant contact with the transom 102 during lifting and lowering of the fairing.

[0191]FIG. 9 depicts a schematic diagram illustrating a view of the fairing, when viewed aft from the transom, corresponding to the view designated by the letters A-A in FIG. 5, in which the fairing is shown unfolded and lowered for operation in displacement mode.

[0192]The fairing, which shells, in order to not clutter the view of its foldable and retractable design, are shown in the embodiment not reinforced with internal frames and stringers, comprises two successively arranged lengthwise portions:—the hollow front part 109 and the after part 110, which are in contact along a longitudinal cylindrical surface corresponding to the peripheral contour of the rear edge of the front part 109 and visible here as contour 901, while the hollow front part 109 has a peripheral leading edge 112 shaped to conform to the lower peripheral edge of the boat's transom.

[0193]The shell of the front part 109 is covered by the upper skin panel 502 forming the upper edge 114 of the front part 109 and the fairing as a whole.

[0194]As can be seen from FIG. 9, the after part 110 does not extend beyond the boundaries of the contour 901, which makes it possible to move the after part 110 forward, fold it and store it inside the hollow front part 109.

[0195]For this purpose the front part 109 is provided with longitudinal inverted T-shaped rails 501 attached from below to the upper skin panel 502, and the after part 110 is provided with longitudinal inverted T-slot sliders 503 structurally connected to the shell of the after part 110 by vertical longitudinal supports 902, so that the sliders 503 of the after part 110 can slide along the rails 501 forward until the after part 110 should stop in the extreme forward position, ensuring the complete placement of the after part 110 inside the cavity of the hollow front part 109.

[0196]To accomplish such folding, the fairing is equipped with a longitudinally arranged and centrally located electric linear actuator, represented here by the only visible in the FIG. 9 front end support 505, which is secured from below to the upper skin panel 502 at the forward extremity of the front part 109 and assumed to be combined with drive.

[0197]The longitudinal thrust of the linear actuator is transmitted to the after part 110, and more specifically to the forward part of the inverted T-slot sliders 503 of the after part 110, via brackets 701, so that if pulled by the linear actuator from the shown rearmost unfolded position, the after part 110 will move (slide along rails 501) forward up to complete placement and folding in the cavity of the hollow front part 109.

[0198]In the embodiment shown in the FIG. 9, the fairing (specifically its front part 109) is suspended from below the swim platform 113 (the cross-section of which is shaded) by means of vertical hydraulic actuators 509, arranged assumably in pairs on both sides of the front part 109 and released to provide the lower operational position of the fairing.

[0199]If retracted, the actuators 509 will lift the fairing (i.e., its front part 109 with the after part 110 folded inside) vertically and transfer it to the upper inactive position, which ensures efficient operation of the boat in planing mode and compactness at high speed and rest. FIG. 10 depicts a schematic diagram illustrating a cross-sectional view of the fairing corresponding to section 3-3 in FIG. 6, and shows the fairing being folded and raised for operation in planing mode or for rest.

[0200]In FIG. 10, where cross sections of all shown components of the fairing are hatched, the cavity of hollow front part 109 with its upper skin panel 502 and the upper edge 114, contains the folded inside after part 110, which configuration corresponds upper inactive and compact state of the fairing.

[0201]To be brought to the compact inactive state shown, the front part 109 is provided with longitudinal inverted T-shaped rails 501 attached from below to the upper skin panel 502, and the after part 110 is provided with longitudinal inverted T-slot sliders 503 structurally connected to the shell of the after part 110 by vertical longitudinal supports 902, so that the sliders 503 of the after part 110 have slid along the rails 501 forward until the after part 110 stopped in the extreme forward position, ensuring the complete placement of the after part 110 inside the cavity of the hollow front part 109.

[0202]To perform such folding, the fairing is equipped with a longitudinally arranged and centrally located electric linear actuator, represented here by the only visible in the FIG. 10 cross section of the linear drive screw 504, which ensured the longitudinal movement of the after part 110 along rails 501 from the rearmost operational position forward to the shown most forward folded position.

[0203]FIG. 11 depicts a schematic diagram illustrating the side elevation view of the aft part of a planing boat, basically similar to boats shown in FIG. 1 and FIG. 3, provided with the transom fairing according to some embodiments, wherein the fairing, suspended on the transom by means of double-lever parallelogram mechanisms, is shown unfolded and lowered for operation in displacement mode.

[0204]In the broken-away stern portion of the hull of the boat shown in the FIG. 11, the planing boat 101 with its substantially vertical transom plane 102, sides 103, planing bottom surfaces 104, chines 106, substantially vertical edges 105 formed by the intersection of transom 102 with the sides 103 and extending upward from the chines 106, the keel line 108 and the trailing edges 107 of the planing bottom surfaces 104, which edges 107 connect the keel line 108 and the chines 106 at their aftermost points, is assumed to be floating on the surface of the water, while submerged to its waterline “WL” corresponding to the stationary displacement state.

[0205]The boat 101 is provided with a movable relative the hull of the boat 101, located aft of transom 102 and foldable fairing comprising two successively arranged along the length of the boat 101 hollow front part 109 and after part 110, which are in contact along a longitudinal cylindrical surface corresponding to contour 111, representing the peripheral contour of the rear edge of the front part 109, while the hollow front part 109 has the upper skin panel 502 with its substantially horizontal upper edge 114, and the peripheral leading edge 112, which peripheral leading edge 112 is shaped to conform to, abuts upon and fits flush with the lower peripheral edge of the transom 102 including the trailing edges 107 and substantially vertical edges 105 up to a level somewhat above the waterline “WL”.

[0206]The after part 110 does not extend beyond the boundaries of the contour 111 in the projection onto the transverse plane, which makes it possible to move the after part 110 forward, fold it and store it inside the hollow front part 109. Such folding can be carried out by not shown here longitudinally arranged electric linear actuators, e.g.

[0207]The hull of the boat 101 is also equipped with a swim platform 113, mounted on the transom 102, extending aftward of the transom 102 and above the waterline “WL”, so that in this mode the substantially horizontal upper edge 114 of the fairing is located somewhat below the platform 113 and above the waterline “WL”, and the platform 113 partially covers the fairing in the plan view, while completely covering the front part 109. In the embodiment shown in the FIG. 11, the fairing (specifically its front part 109) is suspended on the transom 102 by means of double-lever parallelogram mechanisms schematically shown in the conventional cutout 1101 of the side of the front part 109.

[0208]The parallelogram mechanisms comprise the levers 1102 arranged presumably in pairs on both sides of the front part 109 and shown inclined downwards to ensure the lower operational position of the fairing, the front hinges 1103 of the levers 1102, fixed on the transom 102 one above the other vertically, and the rear hinges 1104 of the levers 1102, fixed one above the other vertically on the sides and inside the shell of the front part 109, and are driven by two vertical hydraulic actuators 509, located each on its side of the front part 109 and attached from below to the swim platform 113, as shown in the conventional cutout 1105 of the side part of the swim platform 113.

[0209]The axes of rotation of hinges 1103 and 1104 are substantially normal to the boat's center plane, so that in the case of retraction of hydraulic actuators 509, the parallelogram levers 1102 will rotate clockwise around the axes of the front hinges 1103, when viewed from the starboard side of the boat, from the position in which the levers 1102 are inclined as shown downwards relative to the front hinges 1103, to their upper position, in which the levers 1102 will be inclined upwards relative to the front hinges 1103, resulting in raising the fairing (meaning the front part 109 with the after part 110 folded inside) from its lower operational position to the upper inactive position. Thus, the embodiment shown in FIG. 11 provides the after part of the boat 101 with rounded stern formations, optimal for displacement sailing at low Froude numbers, which ensure a smooth and separation-free flow around the stern of the boat 101 and result in low hydrodynamic resistance in displacement mode (meaning higher hydrodynamic efficiency) leading to a decrease in the power required to propel the boat 101, a decrease in fuel consumption and a corresponding increase in cruising range when sailing in the displacement mode. At the same time, the ability of the fairing to be folded, provided by sectioning the fairing with the after part movable relative to the front one, as well as the ability of the compactly folded fairing to be lifted using parallelogram mechanisms, allow for efficient operation of the boat in the main high-speed mode and eliminates the inconvenience of operation both on the move at high speed and at rest.

[0210]FIG. 12 depicts a schematic diagram illustrating the side elevation view of the aft part of a planing boat, basically similar to boats shown in FIG. 2 and FIG. 4, provided with the transom fairing according to some embodiments, wherein the fairing, suspended on the transom by means of double-lever parallelogram mechanisms, is shown folded and raised into its inactive position ensuring effective operation of the boat in the main planing mode or staying at rest.

[0211]In the broken-away stern portion of the hull of the boat shown in the FIG. 12, the planing boat 101 with its substantially vertical transom plane 102, sides 103, planing bottom surfaces 104, chines 106, substantially vertical edges 105 formed by the intersection of transom 102 with the sides 103 and extending upward from the chines 106, the keel line 108 and the trailing edges 107 of the planing bottom surfaces 104, which edges 107 connect the keel line 108 and the chines 106 at their aftermost points, is assumed to be moving in its main high-speed planing mode or staying at rest.

[0212]The boat 101 is provided with a movable relative the hull of the boat 101, located aft of transom 102 and foldable fairing comprising the hollow front part 109 with its peripheral rear edge 111, the peripheral leading edge 112 adjacent to the transom 102 and the upper skin panel 502 of the shell of the hollow front part 109 with its upper edge 114, and the after part not extending beyond the contour of the edge 111 in projection onto the transverse plane, which made it possible to move the after part forward and fold it inside the cavity of the hollow front part 109, so that the shown fairing is presumed to be folded and only the front part 109 of the folded fairing is visible in the FIG. 12.

[0213]In order to provide efficient, low-drag motion of the boat 101 in its primary high-speed planing mode, the flow of water along the planing bottom of the boat 101 must be separated at the trailing edge 107, for which purpose the trailing edge 107 must be uncovered by means of a transom step 201 formed by the exposed surface of the transom 102 extending substantially vertically from the trailing edge 107.

[0214]This is achieved by raising the folded fairing, i.e. raising the front hollow part 109 adjacent to the transom 102 with the after part folded inside, from the lower operational position of the front part 109 (covering from behind the trailing edge 107 in the displacement mode) to the position somewhat above the edge 107, as shown in the FIG. 12, which exposes the edge 107 and forms the transom step 201 extending from the trailing edge 107 up to the peripheral leading edge 112 of the front part 109.

[0215]In the depicted embodiment of FIG. 12, wherein the boat 101 is equipped with a swim platform 113 completely covering the front part 109 in the plan view, the fairing is raised up to the position where its upper edge 114 touches the lower part of the platform 113, while the compactly folded fairing is completely placed under the swim platform 113, which makes this design perfectly compatible with the swim platform 113, does not increase the dimensions of the boat 101 in any way and practically does not elevate the center of gravity of the boat 101 in any significant way.

[0216]To carry out said lifting of the fairing, in the embodiment shown in the FIG. 12, the fairing (specifically its front part 109) is suspended on the transom 102 by means of double-lever parallelogram mechanisms schematically shown in the conventional cutout 1101 of the side of the front part 109.

[0217]The parallelogram mechanisms comprise the levers 1102 arranged presumably in pairs on both sides of the front part 109 and shown inclined upwards to ensure the high inactive position of the fairing, the front hinges 1103 of the levers 1102, fixed on the transom 102 one above the other vertically, and the rear hinges 1104 of the levers 1102, fixed one above the other vertically on the sides and inside the shell of the front part 109, and are driven by two vertical hydraulic actuators 509 (shown retracted), located each on its side of the front part 109 and attached from below to the swim platform 113, as shown in the conventional cutout 1105 of the swim platform 113.

[0218]The axes of rotation of hinges 1103 and 1104 are substantially normal to the boat's center plane, so that as the result of the retraction of the actuators 509, the parallelogram levers 1102 rotated clockwise around the axes of the front hinges 1103, when viewed from the starboard side of the boat, from the position in which the levers 1102 were inclined downwards relative to the front hinges 1103, to their upper position, in which the levers 1102 are inclined upwards relative to the front hinges 1103, resulting in the fairing (i.e., the front part 109 with the after part folded inside) has risen from its lower operational position to the upper inactive position, ensuring efficient operation in planing mode and a compact configuration of the boat 101 when at high speed or rest.

[0219]FIG. 13 depicts a schematic diagram illustrating a perspective aft bottom view of a boat provided with the transom fairing according to some embodiments, wherein the fairing is shown unfolded and positioned for operation in displacement mode.

[0220]In the FIG. 13, the planing boat 101 (shown upside-down) includes vertical transom 102, sides 103, planing bottom surfaces 104, chines 106, substantially vertical edges 105 formed by the intersection of transom 102 with the sides 103 and extending upward (downward in this inverted view) from the chines 106, the keel line 108 and the trailing edges 107 of the planing bottom surfaces 104. The boat 101 is also equipped with a swim platform 113, mounted on the transom 102, extending aft of the transom 102 and arranged above the waterline in the stationary floating position of the boat 101.

[0221]The boat 101 is provided with a movable relative the hull of the boat 101, located aft of transom 102 and foldable fairing comprising two successively arranged along the length of the boat 101 portions:—the hollow front part 109 and the after part 110, which are in contact along a longitudinal cylindrical surface corresponding to contour 111, representing the peripheral contour of the rear edge of the hollow front part 109, while the front part 109 has the upper edge 114 and the peripheral leading edge 112.

[0222]The peripheral leading edge 112 is shaped to conform to, abuts upon and fits flush with the lower peripheral edge of the transom 102 including the trailing edges 107 and substantially vertical edges 105 up to a level somewhat above the waterline, so that in this unfolded state of the fairing corresponding operation of the boat 101 in displacement mode, the upper edge 114 of the fairing is positioned somewhat below the swim platform 113 (shown here positioned above the platform 113 in this upside-down bottom view of the boat 101) and above the waterline, while the platform 113 partially covers the fairing in the plan view and completely covers the front part 109.

[0223]The fairing, represented in the shown operational position by successively composed front part 109 and after part 110, has a smooth continuous surface and a configuration tapering from the transom 102 further aft both in the plan view and with contours rising (lowering in this upside-down view) gradually from the trailing edges 107 of the bottom. Such a streamlined shape of the fairing, providing a smooth transition from the angular shape of the lower aft section of the planing boat 101, formed by the dihedral bottom 104, flat planes of the sides 103 and the transverse transom plane 102, to the rounded stern formations of the fairing, optimal for displacement vessels sailing at low Froude numbers, ensures a smooth and separation-free flow around the stern of the boat 101 and results in low hydrodynamic resistance in displacement mode (meaning higher hydrodynamic efficiency), which leads to a decrease in the power required to propel the boat 101, a decrease in fuel consumption and a corresponding increase in cruising range when sailing in the displacement mode.

[0224]At the same time, the indicated tapering aftward shape of the fairing suggests that, in projection onto the transverse plane, the after part 110 does not extend beyond the boundaries of the contour 111, corresponding to the contour of the abutment of the after part 110 to the front part 109, and, so, being moved forward, the after part 110 can enter the cavity of the hollow front part 109 to be completely accommodated there, and thus reduce the length of the fairing to the length of the front part 109.

[0225]In order to speed up the removal of water from the fairing cavity and this way to neutralize the negative impact of the excessive masses of water accumulated in the fairing on dynamics and trim of the boat 101, in the shown embodiment the bottom sections of the shell of the front part 109 are provided with drainage holes 1301.

[0226]FIG. 14 depicts a schematic diagram illustrating a perspective aft bottom view of a boat provided with the transom fairing according to some embodiments, wherein the depicted boat represents basically the same boat as shown in FIG. 13, but with the fairing folded and retracted for operation in the main high-speed planing mode, or at rest, when the boat is moored at a berth in a marina, for example.

[0227]In FIG. 14, the planing boat 101 (shown upside-down) with its transom 102, sides 103, planing bottom surfaces 104, chines 106, substantially vertical edges 105 formed by the intersection of transom 102 with sides 103 and extending upward (downward in this inverted view) from the chines 106, the keel line 108 and the trailing edges 107 of the planing bottom surfaces 104, formed by intersection of the transom 102 with bottom surfaces 104, is assumed to be moving in planing mode, which mode requires exposure of the trailing edges 107, or staying at rest. The boat 101 is also equipped with a swim platform 113, mounted on the transom 102 and extending aft of the transom 102.

[0228]The boat 101 is provided with a movable relative the hull of the boat 101, located aft of transom 102 and foldable fairing, shown in its folded and retracted position, corresponding the planing mode or the rest, and comprising the hollow front part 109 with its rear peripheral edge 111, the peripheral leading edge 112, the upper edge 114 and drainage holes 1301, and the after part 110.

[0229]Due to the fact that the fairing in its unfolded state, with the front part 109 and the after part 110 successively arranged along the length of the boat 101 aft of the transom 102, has a rearwardly tapering configuration, the after part 110 of the fairing does not extend beyond the boundaries of the contour 111 in projection onto the transverse plain, and, so, the after part 110 can be moved forward into the cavity of the hollow front part 109. Thus, in the FIG. 14 it is assumed that the after part was pushed into the cavity of the hollow front part 109 and is completely accommodated there in its folded position, which reduces the length of the fairing to the length of its front part 109.

[0230]In order to provide efficient, low-drag motion of the boat 101 in its primary high-speed planing mode, the hydrodynamic lift-generating flow of water along the bottom 104 must be separated at the trailing edge 107, for which purpose the trailing edge 107 must be uncovered by means of a transom step 201 formed by the exposed surface of the transom 102 extending substantially vertically from the trailing edge 107.

[0231]This is achieved in the shown embodiment by raising the folded fairing, i.e. raising the front hollow part 109 adjacent to the transom 102 with the after part 110 folded inside, from the lower operational position of the front part 109 (covering from behind the trailing edge 107 in the displacement mode) to the position somewhat above the edge 107, as shown in the FIG. 14 in the upside-down view, which exposes the edge 107 and forms the transom step 201 extending from the trailing edge 107 up to the peripheral leading edge 112 of the front part 109.

[0232]In the depicted configuration of FIG. 14, where the boat 101 is equipped with a swim platform 113, the fairing represented by the front part 109 has been raised, so that its upper edge 114 touched the lower part of the platform 113.

[0233]By means of this, considering that in this embodiment the swim platform 113 completely covers the front part 109 of the fairing in the plan view, the compactly folded fairing is completely placed under the swim platform 113, which makes this design perfectly compatible with the swim platform 113, does not increase the dimensions of the boat 101 in any way and practically does not elevate the center of gravity of the boat 101 in any significant way.

[0234]It is assumed that all the above operations for folding and retracting the fairing are carried out using (not shown) mechanisms employing hydraulic or electrohydraulic actuators, or electric linear actuators.

[0235]Thus, this embodiment of foldable retractable transom fairing in accordance with the present invention eliminates the disadvantages of bulky single-piece fairings and completely solves the problems of using low-speed fairings on planing boats, providing low hydrodynamic resistance in the displacement mode of motion (i.e., increasing hydrodynamic efficiency), resulting in low power and fuel consumption, and a corresponding increase in the cruising range (i.e., improving the operational properties of boats), without compromising operation in the main high-speed planing mode and at rest, without increasing the dimensions of the boats and without cluttering the stern (which is critical, for example, for fishing boats), while being compatible with swim platforms, without having a significant effect on the position of the center of gravity and thereby not deteriorating the static and dynamic stability.

[0236]FIG. 15 depicts a schematic diagram illustrating a perspective view of the transom fairing according to some embodiments, wherein the fairing, with its shells reinforced with internal frames and stringers, is shown in the unfolded state corresponding operation in displacement mode.

[0237]In the FIG. 15, the fairing comprises two successively arranged lengthwise portions:—the hollow front part 109 and the after part 110, which are in contact along a longitudinal cylindrical surface corresponding to the peripheral contour of the rear edge of the front part 109 and represented by the visible here contour 901, and form a smooth continuous outer surface providing low hydrodynamic resistance in the displacement mode of boat, while the hollow front part 109 has a peripheral leading edge 112 shaped to conform to the lower peripheral edge of the boat's transom.

[0238]The shell of the front part 109 is covered by the upper skin panel 502 forming the upper edge 114 of the front part 109 and the fairing as a whole, while the upper skin panel 502 is conditionally partially removed, which makes it possible to display the internal structure of the fairing.

[0239]As can be seen from FIG. 15, due to the rearwardly tapering configuration of the fairing, the after part 110 does not extend transversely beyond the boundaries of the contour 901, which makes it possible to move the after part 110 forward, fold it and store it inside the hollow front part 109.

[0240]For this purpose the front part 109 is provided with longitudinal inverted T-shaped rails 501, attached from below to the upper skin panel 502 (conditional breaks of vertical members of the inverted T-shaped rails 501 connecting the rails 501 with the upper skin panel 502 are shaded), and the after part 110 is provided with longitudinal inverted T-slot sliders 503 structurally connected to the shell of the after part 110 by vertical longitudinal supports 902, so that the sliders 503 can slide along the rails 501 forward until the after part 110 should stop in the extreme forward position, ensuring the complete placement of the after part 110 inside the cavity of the hollow front part 109.

[0241]The movement of the rear part 110 can be carried out by a longitudinally arranged and centrally located electric linear actuator, not shown here (so as not to clutter the drawing and obscure the view of the fairing structure), which actuator transmits the longitudinal thrust for moving the after part 110 along forward by means of brackets 701 located in the front of the after part 110, and more specifically, the brackets 701 are attached to the front part of the inverted T-slot sliders 503 of the after part 110.

[0242]In the shown embodiment, in order to reinforce the shells of the fairing, the shells are provided with internal frames 1501 with drainage holes 1502, and stringers 1503.

[0243]The embodiment shown in FIG. 15 presupposes retracting the fairing to bring it to the inactive upper position corresponding to the planing or resting mode, using two double-lever parallelogram mechanisms (not shown), which are supposed to be located on sides of the front part 109, so that levers of the parallelogram mechanisms are to be pivotally connected to side structural reinforcements 1504 of the front part 109 featuring as the attachment points the hinge sockets 1505, corresponding to the rear hinges of the levers of the parallelogram mechanisms (while the hinges of the front ends of the levers are attached to the transom).

[0244]FIG. 16 depicts a schematic diagram illustrating the side elevation view of the aft part of a planing boat provided with a transom recess and a fairing foldable into this recess according to some embodiments, wherein the fairing is pivotally connected to the transom and is shown unfolded and lowered for operation in displacement mode.

[0245]In the broken-away stern portion of the hull of the boat shown in the FIG. 16, the planing boat 101 with its transom plane 102, sides 103, planing bottom surfaces 104, chines 106, substantially vertical edges 105 formed by the intersection of transom 102 with the sides 103 and extending upward from the chines 106, the keel line 108 and the trailing edges 107 of the planing bottom surfaces 104, which edges 107 connect the keel line 108 and the chines 106 at their aftermost points, is assumed to be floating on the surface of the water, while submerged to its waterline “WL” corresponding to the stationary displacement state.

[0246]The boat 101 is provided with a movable relative the hull of the boat 101, located aft of transom 102 and foldable fairing comprising two successively arranged along the length of the boat 101:—hollow front part 109 and after part 110, movable relatively to the front part 109, wherein part 109 and part 110 are in contact along a longitudinal cylindrical surface corresponding to contour 111, representing the peripheral contour of the rear edge of the front part 109, while the hollow front part 109 has the substantially horizontal upper edge 114 and the peripheral leading edge 112, which peripheral leading edge 112 is shaped to conform to, abuts upon and fits flush with the lower peripheral edge of the transom 102 including the trailing edges 107 and substantially vertical edges 105 up to a level somewhat above the waterline “WL”.

[0247]Due to the rearwardly tapering configuration of the fairing, the after part 110 does not extend transversely beyond the boundaries of the contour 111, which enables to move the after part 110 forward in direction 1601 and fold it inside the hollow front part 109.

[0248]In the FIG. 16, the hollow front part 109 is pivotally connected to the transom 102 by means of the hinge 1602 structurally attached to the front part 109 by means of the bracket 1603, so that the hollow front part 109 can rotate around the transverse horizontal axis of the hinge 1602 in the direction 1604.

[0249]The stern part of the boat 101 is provided with the recess 1605 protruding into the hull of the boat 101 from the transom 102 forward, which recess 1605 is shown in the conventional cutout 1606 in the stern part of the boat 101.

[0250]Following the above-described design according to the present invention, the after part 110 can be pushed into the cavity of the hollow front part 109 in the direction 1601 until it is completely placed inside the front part 109 and the fairing folded in this way (that is, its front part 109 with the after part 110 folded inside) can be rotated on the hinge 1602 in the direction 1604 at an angle greater than the external angle of inclination of the transom plane to the horizon in order to be completely accommodated inside the recess 1605, thus ensuring the complete retraction of the fairing until its leading edge 112 becomes flush with the transom 102, leaving virtually no protruding parts of the fairing outside the hull of the boat 101.

[0251]The folding of the fairing, i.e. the pushing of the after part 110 into the cavity of the front part 109 in the direction 1601, can be carried out using an electric linear actuator (not visible in this figure), whereas the retraction of the fairing, i.e. the rotation of the front part 109 with the rear part 110 inserted inside in the direction 1604 for placement in the recess 1605, in the embodiment of FIG. 16, supposed to be carried out using the worm gear 1607 driven by the electric motor 1608, shown in the conventional cutout 1606.

[0252]Thus, the embodiment of the fairing according to the present invention shown in FIG. 16 ensures a smooth, continuous flow at the stern of the planing boat 101, resulting in low hydrodynamic resistance (meaning high hydrodynamic efficiency), reduced fuel consumption and a longer cruising range in the displacement mode, and, at the same time, makes it possible to completely remove the fairing from the outside and put it into the boat hull, leaving no protruding parts. This would expose the edges 107 and ensure efficient operation in the main planing mode, would not clutter the stern (which is critical, e.g., for fishing boats), would not affect much the position of the center of gravity and would not increase the dimensions of the boat 101 at all, either at high speed or at rest.

[0253]FIG. 17 depicts a schematic diagram illustrating the side elevation view of the aft part of a planing boat provided with the transom recess and the transom fairing according to some embodiments and basically corresponding to the embodiment shown in FIG. 16, wherein the fairing is pivotally connected to the transom, but is shown folded and completely retracted into the transom recess, so that the boat is to be suitable for operation in planing mode or be at rest.

[0254]In the broken-away stern portion of the hull of the boat shown in the FIG. 17, the planing boat 101 with its transom 102, sides 103, planing bottom surfaces 104, chines 106, substantially vertical edges 105 formed by the intersection of transom 102 with sides 103 and extending upward from the chines 106, the keel line 108 and the trailing edges 107 of the planing bottom surfaces 104, which edges 107 connect the keel line 108 and the chines 106 at their aftermost points, is assumed to be operating in its main high-speed planing mode or be at rest.

[0255]The boat 101 is provided with a movable relative to the hull of the boat 101, foldable and shown folded and retracted fairing comprising the only visible here hollow front part 109 (shown inverted in its retracted position) with its rear (located here forward) peripheral edge 111, peripheral leading (located here behind) edge 112 shaped to conform to the lower peripheral edge of the transom 102 and the horizontal upper (lower in the upside-down position of the front part 109) edge 114, and the after part, which is assumed to be pulled into and folded inside the hollow front part 109, and, thus, is not visible in this figure.

[0256]In the FIG. 17, the hollow front part 109 is pivotally connected to the transom 102 by means of the hinge 1602, so that the hollow front part 109 (with the after part inside, i.e. the whole fairing) was rotated around the transverse horizontal axis of the hinge 1602 clockwise (by 180 degrees from its lower operational position suitable for the displacement mode, i.e. by the angle greater than the external angle of inclination of the transom plane to the horizon 1701) and placed in its upside-down inactive position inside the transom recess 1605 protruding into the hull of the boat 101 from the transom 102 forward, which recess 1605, as well as the front part 109, are shown in the conventional cutout 1606 in the stern part of the boat 101.

[0257]In this case, as a result of the rotation of the front part 109 on the hinge 1602, the upper edge 114 of the front part 109 came into a position of adjoining the lower bottom surface of the recess 1605, the rear peripheral edge 111 came into a position of adjoining the front end of the recess 1605, and the peripheral leading edge 112 became flush with the plane of the transom 102, and, thus, the entire fairing (i.e., the front part 109 with the inserted after part) turned out to be completely hidden in the hull of the boat 101 without any parts protruding outside of the transom 102 and the hull of the boat 101 in general. In application to this embodiment it is assumed that folding of the fairing, i.e. the pushing the after part into the cavity of the hollow front part 109, was carried out using an electric linear actuator (not visible in this figure), whereas the retraction of the fairing, i.e. the rotation of the front part 109 with the rear part inserted inside, for lifting from the lower operational position to the upper inactive position corresponding to placement in the recess 1605, was carried out using the worm gear 1607 driven by the electric motor 1608, shown in the conventional cutout 1606.

[0258]Thus, the embodiment of the fairing according to the present invention shown in FIG. 17 ensures complete removal of the fairing from the outside and its concealment in the hull of the boat 101, leaving no protruding parts, which exposes the step 201 of the trailing edge 107 and, thus, ensures efficient operation in the main planing mode, does not clutter the stern (which is critical, for example, for fishing boats), does not affect much the position of the center of gravity and does not increase the dimensions of the boat 101 at all, either at high speed or at rest.

[0259]FIG. 18 depicts a schematic diagram illustrating the side elevation view of the aft part of a planing boat provided with the transom fairing suspended on the transom by means of double-lever parallelogram mechanisms according to some embodiments, wherein the fairing portions are pivotally connected and shown unfolded and lowered for operation in displacement mode.

[0260]In the broken-away stern portion of the hull of the boat shown in the FIG. 18, the planing boat 101 with its substantially vertical transom 102, sides 103, planing bottom surfaces 104, chines 106, substantially vertical edges 105 formed by the intersection of transom 102 with the sides 103 and extending upward from the chines 106, the keel line 108 and the trailing edges 107 of the planing bottom surfaces 104, which edges 107 connect the keel line 108 and the chines 106 at their aftermost points, is assumed to be floating on the surface of the water, while submerged to its waterline “WL” corresponding to the stationary displacement state.

[0261]The boat 101 is provided with a movable relative the hull of the boat 101, located aft of transom 102 and foldable fairing comprising two successively arranged along the length of the boat 101 and adjacent portions:—the front part 109 with its peripheral leading edge 112 shaped to conform to, abut upon and be flush with the lower peripheral edge of the transom 102 including the trailing edges 107 and substantially vertical edges 105 up to a level somewhat above the waterline “WL”, the peripheral rear edge 111, the upper skin panel 502 and the substantially horizontal upper edge 114, and the after part 110 with its peripheral forward edge 1801 and substantially horizontal upper edge 1802. The shown configuration of the transom fairing, composed of two adjoining parts 109 and 110, assumes the formation of a smooth continuous streamlined surface behind the transom 102, providing a separation-free flow with low hydrodynamic resistance, which is optimal for the displacement mode of movement and thereby improves the operational qualities of the boat 101 in this mode (lower consumption of power, lower fuel consumption and greater cruising range).

[0262]The adjacent upper extremities of the front part 109 and the after part 110, i.e.:—the upper extremity of the rear edge 111 of the front part 109 and the upper extremity of the forward edge 1801 of the after part 110, are pivotally connected by the hinges 1803, so that the after part 110 can rotate relative to the forward part 109 around the transverse horizontal axis of the hinges 1803, and, if it is rotated clockwise in the direction 1804, can be folded forward into a substantially inverted position to be stored over the front part 109. Said rotation may occur until the upper edge 1802 of the after part 110 will coincide with the upper edge 114 of the front part 109 and, so, the upper surface of the after part 110 will contact the upper surface 502 of the front part 109, which will correspond to the angle of rotation of the after part 110 of 180 degrees. (In the case of a hollow front part 109 not provided with the panel 502, the angle of rotation of the after part 110 may be greater than 180 degrees.) The rotation of the after part 110 relative to the front part 109 on the hinges 1803 can be carried out using not shown in the FIG. 18 hydraulic or electrohydraulic actuators, or using worm gears driven by electric motors, as shown for the embodiments in FIG. 16 and FIG. 17.

[0263]In the embodiment shown in the FIG. 18, like in the embodiment of the FIG. 11, the fairing (specifically its front part 109) is suspended on the transom 102 by means of double-lever parallelogram mechanisms schematically shown in the conventional cutout 1101 of the side of the front part 109, which is similar to the cutout of the FIG. 11.

[0264]The conditional breakout of the upper panel 502 of the front part 109, visible in the same cutout 1101, is shown here shaded.

[0265]The parallelogram mechanisms comprise the levers 1102 arranged presumably in pairs on both sides of the front part 109 and shown inclined downwards to ensure the lower operational position of the fairing, the front hinges 1103 of the levers 1102, fixed on the transom 102 one above the other vertically, and the rear hinges 1104 of the levers 1102, fixed one above the other vertically on the sides and inside the shell of the front part 109, and are driven by two vertical hydraulic actuators 509, located each on its side of the front part 109 and fixed to the transom 102 by means of brackets 1805.

[0266]The axes of rotation of hinges 1103 and 1104 are substantially normal to the boat's center plane, so that in the case of retraction of hydraulic actuators 509, the parallelogram levers 1102 will rotate clockwise around the axes of the front hinges 1103, when viewed from the starboard side of the boat, from the position in which the levers 1102 are inclined as shown downwards relative to the front hinges 1103, to their upper position, in which the levers 1102 will be inclined upwards relative to the front hinges 1103, resulting in raising the fairing (meaning the front part 109 with the after part 110 folded over it) from its lower operational position to the upper inactive position. Thus, the embodiment shown in FIG. 18 provides the after part of the boat 101 with rounded stern formations, optimal for displacement sailing at low Froude numbers, which ensure a smooth and separation-free flow around the stern of the boat 101 and result in low hydrodynamic resistance in displacement mode (meaning higher hydrodynamic efficiency), which leads to a decrease in the power required to propel the boat 101, a decrease in fuel consumption and a corresponding increase in cruising range when sailing in the displacement mode. At the same time, the ability to fold the fairing, provided by sectioning the fairing and the hinged connection of its parts, as well as the ability to lift the compactly folded fairing using parallelogram mechanisms, allows for efficient operation of the boat in the main high-speed mode and eliminates the inconvenience of operation both on the move and at rest.

[0267]FIG. 19 depicts a schematic diagram illustrating the side elevation view of the aft part of a planing boat, basically similar to the boat shown in FIG. 18, provided with the transom fairing according to some embodiments, wherein the fairing portions are pivotally connected, while the fairing, suspended on the transom by means of double-lever parallelogram mechanisms, is shown folded and raised into its inactive position ensuring effective operation of the boat in the main planing mode or staying at rest.

[0268]In the broken-away stern portion of the hull of the boat shown in the FIG. 19, the planing boat 101 with its substantially vertical transom plane 102, sides 103, planing bottom surfaces 104, chines 106, substantially vertical edges 105 formed by the intersection of transom 102 with the sides 103 and extending upward from the chines 106, the keel line 108 and the trailing edges 107 of the planing bottom surfaces 104, which edges 107 connect the keel line 108 and the chines 106 at their aftermost points, is assumed to be moving in its main high-speed planing mode or staying at rest.

[0269]The boat 101 is provided with a movable relative the hull of the boat 101, located aft of transom 102 and foldable fairing comprising two successively arranged along the length of the boat 101 and adjacent portions:—the front part 109 with its peripheral leading edge 112 shaped to conform to the peripheral edge of the transom 102, the peripheral rear edge 111, the upper skin panel 502 and the substantially horizontal upper edge 114, and the after part 110 with its peripheral forward edge 1801 (located at the rear in the shown inverted position of the after part 110) and substantially horizontal upper edge 1802 (located at the bottom in the shown inverted position of the after part 110).

[0270]The adjacent extremities, i.e.:—the upper extremity of the rear edge 111 of the front part 109 and the upper extremity of the forward edge 1801 of the after part 110 (shown as the low rear extremity in this inverted position of the after part 110), are pivotally connected by the hinge 1803, so that the FIG. 19 depicts the after part 110 rotated relative to the forward part 109 around the transverse horizontal axis of the hinge 1803 clockwise by 180 degrees, folded forward in the inverted position and stored over the front part 109, whereby the upper edge 1802 of the after part 110 came into contact with the upper edge 114 of the front part 109 and, thus, the upper surface of the after part 110 came into contact with the upper surface 502 of the front part 109.

[0271]It is assumed that the rotation of the after part 110 relative to the front part 109 on the hinges 1803 was carried out using not shown in the FIG. 19 hydraulic or electrohydraulic actuators, or using worm gears driven by electric motors, as shown for the embodiments in FIG. 16 and FIG. 17.

[0272]As a result of this folding, the fairing acquires a more compact configuration and its longitudinal dimension (that is, its protrusion aft beyond the transom 102) is reduced to the length of the front part 109, which makes operation of the boat 101 more convenient both in planing mode and at rest.

[0273]In order to provide efficient, low-drag motion of the boat 101 in its primary high-speed planing mode, the flow of water along the planing bottom 104 of the boat 101 must be separated at the trailing edges 107, for which purpose the trailing edges 107 must be uncovered by means of a transom step 201 formed by the exposed surface of the transom 102 extending substantially vertically from the trailing edge 107.

[0274]This is achieved by raising the folded fairing, i.e. raising the front part 109 adjacent to the transom 102 with the after part 110 folded over it, from the lower operational position of the front part 109 (covering from behind the trailing edge 107 in the displacement mode) to the position somewhat above the edge 107, as shown in the FIG. 19, which exposes the edges 107 and forms the transom step 201 extending from the trailing edge 107 up to the peripheral leading edge 112 of the front part 109.

[0275]To carry out said lifting of the fairing, in the embodiment shown in the FIG. 19, the fairing (specifically its front part 109) is suspended on the transom 102 by means of double-lever parallelogram mechanisms schematically shown in the conventional cutout 1101 of the side of the front part 109. The conditional breakout of the upper panel 502 of the front part 109, visible in the same cutout 1101, is shown here shaded.

[0276]The parallelogram mechanisms comprise the levers 1102 arranged presumably in pairs on both sides of the front part 109 and shown inclined upwards to ensure the high inactive position of the fairing, the front hinges 1103 of the levers 1102, fixed on the transom 102 one above the other vertically, and the rear hinges 1104 of the levers 1102, fixed one above the other vertically on the sides and inside the shell of the front part 109, and are driven by two vertical hydraulic actuators 509 (shown retracted), located each on its side of the front part 109 and fixed to the transom 102 by means of brackets 1805.

[0277]The axes of rotation of hinges 1103 and 1104 are substantially normal to the boat's center plane, so that, as the result of the retraction of the actuators 509, the parallelogram levers 1102 rotated clockwise around the axes of the front hinges 1103, when viewed from the starboard side of the boat, from the position in which the levers 1102 were inclined downwards relative to the front hinges 1103, to their upper position, in which the levers 1102 are inclined upwards relative to the front hinges 1103, resulting in the fairing (meaning the front part 109 with the after part 110 folded over it) has risen from its lower operational position to the upper inactive position, ensuring efficient operation in planing mode and a compact configuration of the boat 101 when at rest.

[0278]FIG. 20 depicts a schematic diagram illustrating the stern view of a boat according to some embodiments, wherein the boat is provided with a foldable transom fairing, comprising pivotally connected portions, shown unfolded in its lower operational position, corresponding to displacement mode, and consisting of two symmetrical relative to the center plane halves, each suspended on the transom by means of a parallelogram mechanism with longitudinal axes of rotation of levers.

[0279]The planing boat 101 floats, being submerged to its waterline “WL” corresponding to the stationary displacement state, and features a substantially vertical transom 102, the lower peripheral edge of which is closed and not visible here, as well as sides 103.

[0280]The boat 101 is provided with a movable relative the hull of the boat 101, located aft of transom 102 and foldable fairing, shown in its unfolded lower operational position, corresponding low-speed displacement mode of the boat 101, and consisting of two symmetrical relative center plane halves.

[0281]Each of the halves comprises two successively arranged along the length of the boat 101 portions:—the front part 109 with its peripheral leading edge 112, which is shaped to conform to, abuts upon and fits flush with the lower peripheral edge of the transom 102, rear peripheral edge 111, outlining the transom plane of the front part 109, and the upper edge 114, and the after part 110 with its forward peripheral edge 1801, outlining the front plane of the after part 110, and upper edge 1802, whereas the transom plane of the front part 109 and the front plane of the after part 110 are adjacent and in flush contact, so that the edges 111 and 1801 are conforming and abutting.

[0282]The fairing, represented in the shown operational position composed by the two transversely symmetrical halves and successively arranged lengthwise front parts 109 and after parts 110, is assumed to have a smooth continuous surface forming a streamlined shape of the fairing providing a smooth transition from the dihedral angular shape of the lower aft section of the planing boat 101 to the rounded stern formations optimal for displacement mode, which ensures a smooth and separation-free flow around the stern of the boat 101 and results in low hydrodynamic resistance in displacement mode (meaning higher hydrodynamic efficiency), a decrease in the power required to propel the boat 101, a decrease in fuel consumption and a corresponding increase in cruising range when sailing in the displacement mode.

[0283]The adjacent upper extremities of the front part 109 and the after part 110 of each half, i.e.:—the upper extremity of the rear edge 111 of the front part 109 and the upper extremity of the forward edge 1801 of the after part 110, are pivotally connected by the hinges 1803, so that the after part 110 can rotate relative to the forward part 109 around the transverse horizontal axis of the hinges 1803, and, if rotated, can be folded forward into a substantially inverted position to be stored over the front part 109. Said rotation may occur until the upper edge 1802 of the after part 110 will coincide with the upper edge 114 of the front part 109 and, so, the upper surface of the after part 110 will contact the upper surface of the front part 109, which in this embodiment will correspond to the angle of rotation of the after part 110 of 180 degrees. The rotation of the after part 110 relative to the front part 109 on the hinges 1803 can be carried out using not shown in the FIG. 20 hydraulic or electrohydraulic actuators, or using worm gears driven by electric motors, as shown for the embodiments in FIG. 16 and FIG. 17.

[0284]In the embodiment shown in the FIG. 20, each half of the fairing (specifically its front part 109) is suspended on the transom 102 by means of double-lever parallelogram mechanism schematically shown in the conventional cutout 2001.

[0285]The parallelogram mechanism of each half comprises two levers 1102 shown inclined downwards to ensure the lower operational position of the fairing, the inner, closer to the center plane hinges 1103 of the levers 1102, fixed on the transom 102 one above the other vertically, and the outer hinges 1104 of the levers 1102, fixed one above the other vertically on the structure of the front part 109, and is driven by the vertically arranged hydraulic actuator 509 fixed to the transom 102 by means of the bracket 1805. The axes of rotation of hinges 1103 and 1104 are substantially longitudinal along the length of the boat, so that in the case of retraction of hydraulic actuator 509, the parallelogram levers 1102 of the port side will rotate clockwise (while the levers of the starboard side will rotate counter-clockwise) around the axes of the inner hinges 1103, when viewed at the stern of the boat, from the position in which the levers 1102 are inclined as shown downwards relative to the inner hinges 1103, to their upper position, in which the levers 1102 will be inclined upwards relative to the inner hinges 1103, resulting in raising the fairing (meaning the front part 109 with the after part 110 folded over it) from its lower operational position to the upper inactive position ensuring exposure of the trailing edges of the bottom of the boat 101 required for planing mode. Thus, in addition to providing a smooth flow at the stern of the boat 101 in the depicted in the FIG. 20 displacement mode, the foldability and retractability of the fairing following the shown embodiment of this invention, that is the ability of the fairing to fold to a compact size protruding aft of the transom by only the length of the front part 109 and the ability to raise to the upper inactive position above the trailing edges of the bottom of boat 101, ensures also efficient operation of the boat 101 in the main planing mode and convenient minimum-dimensions operation both on the move at high speed and at rest.

[0286]FIG. 21 depicts a schematic diagram illustrating the stern view of a boat according to some embodiments, wherein the boat is operated in its main high-speed planing mode or is at rest, and is provided with a foldable transom fairing consisting of two halves symmetrical relative to the center plane, shown in their upper inactive position, while each half of the fairing is suspended on the transom by means of a parallelogram mechanism with longitudinal axes of rotation of the levers and comprises pivotally connected parts, shown with the after part folded over the front part.

[0287]In this diagram the planing boat 101 with its sides 103, chines 106, the keel line 108 and the transom 102 with its lower peripheral edge comprising substantially vertical edges 105, formed by intersection of the transom 102 with sides 103, and the trailing edges 107 of the planing bottom surfaces connecting the aftermost points of the keel line 108 and chines 106, is assumed to be moving in planing mode, which mode requires exposure of the trailing edges 107, or staying at rest.

[0288]The boat 101 is provided with the foldable and retractable fairing shown in its folded and retracted position, corresponding to the planing mode or the rest, which fairing locates aft of transom 102 and, as in the embodiment shown in FIG. 20, consists of two symmetrical relative center plane halves.

[0289]Each of the halves comprises two portions:—the front part 109 with its peripheral leading edge 112, which is shaped to conform to the lower peripheral edge of the transom 102, rear peripheral edge 111, outlining the transom plane of the front part 109, and the upper edge 114, and the after part 110 (shown here in the inverted position) with its forward peripheral edge 1801, outlining the front plane of the after part 110 (which is viewed at the rear of the after part 110 in its inverted position).

[0290]The adjacent extremities of the front part 109 and the after part 110 of each half, i.e.:—the upper extremity of the rear edge 111 of the front part 109 and the upper (in the unfolded state) extremity of the forward edge 1801, which is positioned here at the bottom of inverted after part 110, are pivotally connected by the hinges 1803, so that, compared to the embodiment of FIG. 20, the after part 110 was rotated relative to the front part 109 around the transverse horizontal axis of hinges 1803 by 180 degrees, and was folded forward into the shown inverted position to be stored over the front part 109. It is assumed that the rotation of the after part 110 relative to the front part 109 on the hinges 1803 was carried out using hydraulic or electrohydraulic actuators not shown in FIG. 21, or using worm gears driven by electric motors, as shown in the embodiments in FIG. 16 and FIG. 17.

[0291]In the embodiment shown in the FIG. 21, each half of the fairing (specifically its front part 109) is suspended on the transom 102 by means of double-lever parallelogram mechanism schematically shown in the conventional cutout 2101.

[0292]The parallelogram mechanism of each half comprises two levers 1102 shown inclined upwards to ensure the upper inactive position of the fairing, the inner, closer to the center plane hinges 1103 of the levers 1102, fixed on the transom 102 one above the other vertically, and the outer hinges 1104 of the levers 1102, fixed one above the other vertically on the structure of the front part 109, and is driven by the vertically arranged hydraulic actuator 509 fixed to the transom 102 by means of the bracket 1805.

[0293]The axes of rotation of hinges 1103 and 1104 are substantially longitudinal along the length of the boat, so that, compared to the embodiment of FIG. 20, because of the shown retracted state of hydraulic actuator 509, the parallelogram levers 1102 of the port side have rotated clockwise (while the levers of the starboard side have rotated counter-clockwise) around the axes of the inner hinges 1103, when viewed at the stern of the boat, from the position in which the levers 1102 were inclined downwards relative to the inner hinges 1103, to their shown upper position, in which the levers 1102 are inclined upwards relative to the inner hinges 1103.

[0294]As the result of said rotation of the levers, the fairing (meaning the front part 109 with the after part 110 folded over it) has raised from its lower operational position to the upper inactive position ensuring exposure of the trailing edges 107 of the bottom of the boat 101 and formation of the step 201 required for the assumed planing mode.

[0295]Thus, due to the foldability and retractability of the fairing in accordance with the present invention, the fairing of the embodiment shown in FIG. 21 was folded to a compact size, protruding beyond the transom only by the length of the front part 109, and was lifted to the upper inactive position above the rear edges 107 of the bottom of the boat 101, ensuring efficient operation of the boat 101 in the main planing mode and convenient operation with minimal dimensions both on the move at high speed and at rest.

[0296]FIG. 22 depicts a schematic diagram illustrating the aft view of a fairing according to some embodiments, wherein the fairing is submerged to the waterline corresponding to the stationary displacement state, shown unfolded and deployed for operation in displacement and transitional modes, and provided with lateral flow deflectors.

[0297]In the FIG. 22, the fairing, submerged up to the waterline “WL”, comprises two successively arranged lengthwise portions:—the front part 109 and the after part 110, which are in contact along the contour 111, while the front part 109 has a peripheral leading edge 112, which is shaped to conform to, abuts upon and fits flush with the lower peripheral edge of boat's transom up to the level of horizontal upper edge 114.

[0298]The embodiment of fairing shown in the FIG. 22 is provided with flow deflectors 2201 protruding transversely outward of sides of the fairing, arranged along the sides of the fairing and located somewhat above the waterline “WL”.

[0299]The concave lower surfaces of the deflectors 2201 are formed by bending the upper portions of the cross-sectional contours of the fairing outward up to substantially horizontal orientation at the outer edges of the deflectors 2201. That is, the tangents to the contours of the cross-sections of the fairing at the lower outer edges of the deflectors are substantially parallel to the horizon.

[0300]When the trim angle increases in the transitional mode of the boat's movement, the deflectors 2201 being inclined towards the stern acquire a pitch position, contact and interact with the flow, as a result of which additional dynamic lifting force is generated, causing a nose-down moment that reduces the trim angle of the boat, which reduces the residual drag and this way increases the hydrodynamic efficiency of the boat in the transition mode (Fr_D between 1 and 3). Thus, the fairing equipped with side deflectors 2201 ensures efficient use in the transitional mode with relative speeds above Fr_D=1.

[0301]At the same time, the design of the deflectors 2201 used in this embodiment of the transom fairing according to this invention does not increase the length of the fairing and does not have any effect on the flow around the fairing in the displacement mode, so that the fairing can be given an optimal shape providing minimal resistance.

[0302]FIG. 23 depicts a schematic diagram illustrating a perspective aft bottom view of a boat provided with the transom fairing according to some embodiments, wherein the fairing is shown unfolded and positioned for operation in displacement and transitional modes, and provided with lateral flow deflectors of the design similar to the FIG. 22.

[0303]In the FIG. 23, the planing boat 101 (shown upside-down) with its substantially vertical transom 102, sides 103, planing bottom surfaces 104, chines 106, substantially vertical edges 105 formed by the intersection of transom 102 with the sides 103 and extending upward (downward in this inverted view) from the chines 106, the keel line 108 and the trailing edges 107 of the planing bottom surfaces 104. The boat 101 is also equipped with a swim platform 113, mounted on the transom 102, extending aft of the transom 102 and arranged above the waterline in the stationary floating position of the boat 101. The boat 101 is provided with a movable relative the hull of the boat 101, located aft of transom 102 and foldable fairing comprising two successively arranged lengthwise portions:—the front part 109 and the after part 110, movable relatively the part 109, which are in contact along a longitudinal cylindrical surface corresponding to contour 111, representing the peripheral contour of the rear edge of the front part 109, while the front part 109 has the upper (lower here) edge 114 and the peripheral leading edge 112. The peripheral leading edge 112 is shaped to conform to, abuts upon and fits flush with the lower peripheral edge of the transom 102 including the trailing edges 107 and substantially vertical edges 105 up to the upper edge 114, so that in this unfolded state of the fairing corresponding operation of the boat 101 in displacement and transitional modes, the upper edge 114 of the fairing is positioned somewhat below the swim platform 113 (shown here positioned above the platform 113 in this upside-down bottom view of the boat 101) and above the waterline, while the platform 113 completely covers the front part 109 in the plan view.

[0304]The fairing, represented in the shown operational position by successively composed front part 109 and after part 110, has a smooth continuous surface and a configuration tapering from the transom 102 further aft both in the plan view and with contours rising (lowering in this upside-down view) gradually from the trailing edges 107 of the bottom. Such a streamlined shape of the fairing, providing a smooth transition from the dihedral and angular shape of the lower aft section of the planing boat 101, formed by substantially flat planes of the sides 103, bottom 104 and transom 102, to the rounded stern formations of the fairing, optimal for displacement vessels sailing at low Froude numbers, ensures a smooth and separation-free flow around the stern of the boat 101 and results in low hydrodynamic resistance in displacement mode (meaning higher hydrodynamic efficiency), which leads to a decrease in the power required to propel the boat 101, a decrease in fuel consumption and a corresponding increase in cruising range when sailing in the displacement mode.

[0305]In order to speed up the removal of water from the fairing cavity and this way to neutralize the negative impact of the excessive masses of water accumulated in the fairing on dynamics and trim of the boat 101, in the shown embodiment the bottom sections of the shell of the front part 109 are provided with drainage holes 1301.

[0306]The embodiment of fairing shown in the FIG. 23 is provided with lateral flow deflectors 2201 protruding outwardly of sides of the fairing, arranged along the sides of the fairing and assumingly above the waterline of the boat in its stationary displacement position.

[0307]The concave lower (upper in this inverted view) surfaces of the deflectors 2201 are formed by bending the upper portions of the cross-sectional contours of the fairing outward up to substantially horizontal orientation at the outer edges of the deflectors 2201. That is, the tangents to the contours of the cross-sections of the fairing at the lower outer edges of the deflectors are substantially parallel to the horizon.

[0308]Due to the assumed location of the deflectors 2201 above the static waterline, they do not affect the flow around the fairing in displacement mode, as a result of which the part of the fairing submerged to the waterline can be given an optimal shape for this mode.

[0309]When the trim angle increases in the transitional mode of the boat's movement, the deflectors 2201 being inclined towards the stern acquire a pitch position, contact and interact with the flow, as a result of which additional dynamic lifting force is generated, causing a nose-down moment that reduces the trim angle of the boat, which reduces the residual drag and this way increases the hydrodynamic efficiency of the boat in the transition mode (Fr_D between 1 and 3). Thus, the fairing equipped with side deflectors 2201 ensures efficient use in the transitional mode with relative speeds above Fr_D=1.

[0310]At the same time, the design of the deflectors 2201 used in this embodiment of the transom fairing according to this invention does not increase the length of the fairing.

[0311]FIG. 24 depicts a schematic diagram illustrating the side elevation view of the aft part of a planing boat, provided with the transom fairing according to some embodiments, wherein the fairing, unfolded and lowered for operation in displacement mode, is shown in section along the center plane, while the front part of the fairing is suspended on the transom by means of parallelogram mechanisms and the after part of fairing can slide forward along rails structurally connected to boat's swim platform.

[0312]In the broken-away stern portion of the hull of the boat shown in the FIG. 24, the planing boat 101 with its substantially vertical transom plane 102, sides 103, planing bottom surfaces 104, chines 106, substantially vertical edges 105 formed by the intersection of transom 102 with the sides 103 and extending upward from the chines 106, the keel line 108 and the trailing edges 107 of the planing bottom surfaces 104, which edges 107 connect the keel line 108 and the chines 106 at their aftermost points, is assumed to be floating on the surface of the water, while submerged to its waterline “WL” corresponding to the stationary displacement state.

[0313]The boat 101 is provided with a movable relative the hull of the boat 101, located aft of transom 102 and foldable fairing, which center plane section is shown in unfolded lower operational position, corresponding low-speed displacement mode of the boat 101.

[0314]The fairing, which shells, in order to not clutter the view of its foldable and retractable design, are shown in the embodiment not reinforced with internal frames and stringers, comprises two successively arranged along the length of the boat 101 portions:—the hollow front part 109 and the after part 110 (the sections of their shells by the center plane are hatched), which are in contact along the contour 111, representing the peripheral contour of the rear edge of the front part 109, while the hollow front part 109 has a peripheral leading edge 112, which peripheral leading edge 112 is shaped to conform to, abuts upon and fits flush with the lower peripheral edge of the transom 102 including the trailing edges 107 and substantially vertical edges 105 up to a level somewhat above the waterline “WL”.

[0315]The hull of the boat 101 is also equipped with a swim platform 113, mounted on the transom 102, extending aftward of the transom 102 and above the waterline “WL”, so that in this mode the substantially horizontal upper edge of the fairing 114 is located somewhat below the platform 113 and above the waterline “WL”, and the platform 113 partially covers the fairing in the plan view, while completely covering the front part 109. The fairing, represented in the shown operational position by successively composed front part 109 and after part 110, is assumed to have a smooth continuous surface and a configuration tapering from the transom 102 further aft both in the plan view and, as shown in this side elevation view, with contours rising gradually from the trailing edges 107 of the bottom to the waterline “WL”. Such a streamlined shape of the fairing, providing a smooth transition from the angular shape of the lower aft section of the planing boat 101, formed by the dihedral bottom 104, flat planes of the sides 103 and the transverse transom plane 102, to the rounded stern formations, optimal for displacement vessels sailing at low Froude numbers, ensures a smooth and separation-free flow around the stern of the boat 101 and results in low hydrodynamic resistance in displacement mode (meaning higher hydrodynamic efficiency), which leads to a decrease in the power required to propel the boat 101, a decrease in fuel consumption and a corresponding increase in cruising range when sailing in the displacement mode. At the same time, the indicated tapering aftward shape of the fairing suggests that the after part 110 does not extend beyond the boundaries of said contour 111, and thus the after part 110 can be moved (e.g., shifted lengthwise) forward for folding and storage inside the hollow front part 109.

[0316]For this purpose the hollow from below swim platform 113 is provided with two longitudinal inverted T-shaped rails 501 attached in inclined position from below to the bottom of the hollow swim platform 113, along which correspondingly inclined inverted T-slot sliders 503, structurally connected to the shell of the after part 110 by vertical longitudinal supports 902, can slide forward until the after part 110 should stop in its extreme forward position, ensuring the complete placement of the after part 110 under the swim platform 113, while being located inside the cavity of the hollow front part 109. In this case, the inclination of the rails 501 and the sliders 503 ensures the lifting of the after part 110 when moving forward, so that it can be folded in the upper inactive position of the fairing corresponding to the high-speed planing mode and rest.

[0317]To perform such folding, the embodiment of FIG. 24 provides a longitudinally arranged and centrally located electric linear actuator, shown in the conventional breakout 510 of the side part of the swim platform 113, which actuator ensures longitudinal movement of the after part 110 and comprises the linear drive screw 504, supported by the front end support 505 (combined with drive) and rear end support 506, secured from below to the swim platform 113 in its front and rear extremities, respectively, and the ball nut 507 of the drive attached to the front end of the after part 110 by brackets (not shown), which ball nut 507, in the shown operational position of completely unfolded fairing, is brought along the linear drive screw 504 to the rearmost position of the linear actuator.

[0318]The rotation of the linear drive screw 504, provided by the electric motor 508 through the drive of the front end support 505, leads to the longitudinal movement of the ball nut 507, which pulls forward or pushes back the after part 110.

[0319]In the embodiment shown in the FIG. 24, the front part 109 of the fairing is suspended on the transom 102 by means of double-lever parallelogram mechanisms.

[0320]The parallelogram mechanisms comprise the levers 1102 arranged presumably in pairs on both sides of the front part 109 and shown inclined downwards to ensure the lower operational position of the fairing, the front hinges 1103 of the levers 1102, fixed on the transom 102 one above the other vertically, and the rear hinges 1104 of the levers 1102, fixed one above the other vertically on the sides and inside the shell of the front part 109, and are driven by two vertical hydraulic actuators 509, located each on its side of the front part 109 and attached from below to the swim platform 113.

[0321]The axes of rotation of hinges 1103 and 1104 are substantially normal to the boat's center plane, so that in the case of retraction of hydraulic actuators 509, the parallelogram levers 1102 will rotate clockwise around the axes of the front hinges 1103, when viewed from the starboard side of the boat, from the position in which the levers 1102 are inclined as shown downwards relative to the front hinges 1103, to their upper position, in which the levers 1102 will be inclined upwards relative to the front hinges 1103, resulting in raising the front part 109 of the fairing from its lower operational position to the upper inactive position.

[0322]Thus, the embodiment shown in FIG. 24 provides the after part of the boat 101 with rounded stern formations, optimal for displacement sailing at low Froude numbers, which ensure a smooth and separation-free flow around the stern of the boat 101 and result in low hydrodynamic resistance in displacement mode (meaning higher hydrodynamic efficiency) leading to a decrease in the power required to propel the boat 101, a decrease in fuel consumption and a corresponding increase in cruising range when sailing in the displacement mode. At the same time, the ability of the fairing to be folded, provided by sectioning the fairing with the after part 110 movable forward, as well as the ability of the front part 109 of the fairing to be lifted using parallelogram mechanisms, allow for efficient operation of the boat in the main high-speed mode and eliminates the inconvenience of operation both on the move at high speed and at rest.

[0323]FIG. 25 depicts a schematic diagram illustrating the side elevation view of the aft part of a planing boat provided with the transom fairing according to some embodiments, wherein the fairing, folded and lifted for operation in planing mode or for rest by means of raising the front part of the fairing by parallelogram mechanisms and sliding the after part forward along rails structurally connected to boat's swim platform, is shown in section along the center plane.

[0324]In the broken-away stern portion of the hull of the boat shown in the FIG. 25, the planing boat 101 with its substantially vertical transom plane 102, sides 103, planing bottom surfaces 104, chines 106, substantially vertical edges 105 formed by the intersection of transom 102 with the sides 103 and extending upward from the chines 106, the keel line 108 and the trailing edges 107 of the planing bottom surfaces 104, which edges 107 connect the keel line 108 and the chines 106 at their aftermost points, is assumed to be moving in its main high-speed planing mode or staying at rest. The hull of the boat 101 is also equipped with a swim platform 113 mounted on the transom 102 and extending aftward of the transom 102 The boat 101 is provided with a movable relative the hull of the boat 101, located aft of transom 102 and foldable fairing, which center plane section is shown in the folded upper inactive position.

[0325]The fairing, which shells are shown in the embodiment not reinforced with internal frames and stringers, comprises the hollow front part 109 with its peripheral rear edge 111 and the peripheral leading edge 112 adjacent to the transom 102, and the after part 110 not extending beyond the contour of the edge 111 in projection onto the transverse plane in deployed position, which enabled to move it forward and fold it inside the cavity of the hollow front part 109 (the sections of their shells by the center plane are hatched). For this purpose the hollow from below swim platform 113 is provided with longitudinal inverted T-shaped rails 501 attached in inclined position from below to the bottom of the hollow swim platform 113, along which correspondingly inclined inverted T-slot sliders 503, structurally connected to the shell of the after part 110 by vertical longitudinal supports 902, slid forward until the after part 110 stopped in its extreme forward position, ensuring the complete placement of the after part 110 under the swim platform 113, while being located inside the cavity of the hollow front part 109. The inclination of the rails 501 and the sliders 503 ensured the lifting of the after part 110 when it moved forward, so that the after part 110 has come to the upper folded state corresponding to the upper inactive position of the fairing in the high-speed planing mode and rest.

[0326]To perform such folding, the embodiment of FIG. 25 provides a longitudinally arranged and centrally located electric linear actuator, shown in the conventional breakout 510 of the side part of the swim platform 113, which actuator ensures longitudinal movement of the after part 110 and comprises the linear drive screw 504, supported by the front end support 505 (combined with drive) and rear end support 506, secured from below to the swim platform 113 in its front and rear extremities, respectively, and the ball nut 507 of the drive attached to the front end of the after part 110 by brackets (not shown), which ball nut 507, in the shown folded state of the after part 110 (and the fairing as a whole), is brought along the linear drive screw 504 to the most forward position of the actuator. The rotation of the linear drive screw 504, provided by the electric motor 508 through the drive of the front end support 505, leads to the longitudinal movement of the ball nut 507, which pulls forward or pushes back the after part 110.

[0327]In order to provide efficient, low-drag motion of the boat 101 in its primary high-speed planing mode, the flow of water along the planing bottom of the boat 101 must be separated at the trailing edges 107, for which purpose the trailing edges 107 must be uncovered by means of a transom step 201 formed by the exposed surface of the transom 102 extending substantially vertically from the trailing edges 107. This is achieved by raising the front hollow part 109 adjacent to the transom 102 from the lower operational position of the front part 109 (covering from behind the trailing edges 107 in the displacement mode) to the position somewhat above the edges 107, as shown in the FIG. 25, which exposes the edges 107 and forms the transom step 201 extending from the trailing edges 107 up to the peripheral leading edge 112 of the front part 109.

[0328]To carry out said raising, the front part 109 of the fairing is suspended on the transom 102 by means of double-lever parallelogram mechanisms. The parallelogram mechanisms comprise the levers 1102 arranged presumably in pairs on both sides of the front part 109, the front hinges 1103 of the levers 1102, fixed on the transom 102 one above the other vertically, and the rear hinges 1104 of the levers 1102, fixed one above the other vertically on the sides and inside the shell of the front part 109, and are driven by two vertical hydraulic actuators 509 (shown retracted), located each on its side of the front part 109 and attached from below to the swim platform 113.

[0329]The axes of rotation of hinges 1103 and 1104 are substantially normal to the boat's center plane, so that as the result of the retraction of the actuators 509, the parallelogram levers 1102 rotated clockwise around the axes of the front hinges 1103, when viewed from the starboard side of the boat, from the position in which the levers 1102 were inclined downwards relative to the front hinges 1103, to their upper position, in which the levers 1102 are inclined upwards relative to the front hinges 1103, resulting in the front part 109 has risen from its lower operational position to the upper inactive position, ensuring efficient operation in planing mode.

[0330]Thus, by means of sliding the after part 110 forward and lifting the front part 109, the compactly folded fairing of this embodiment is completely placed under the swim platform 113, which makes this design perfectly compatible with the swim platform 113, does not increase the dimensions of the boat 101 in any way, which eliminates the inconvenience of operation both on the move at high speed and at rest, and practically does not elevate the center of gravity of the boat 101 in any significant way.