WO2024116115A1

WO2024116115A1 - Hydrofoil assembly for a watercraft with articulated strut and watercraft with said hydrofoil assembly

Info

Publication number: WO2024116115A1
Application number: PCT/IB2023/062077
Authority: WO
Inventors: Davide TAGLIAPIETRA; Ricardo BENCATEL; Anders BRINGDAL; Sue PUTALLAZ
Original assignee: Mobyfly Sa
Priority date: 2022-11-30
Filing date: 2023-11-30
Publication date: 2024-06-06

Abstract

The invention concerns a hydrofoil assembly (20) for a watercraft (10) comprising a strut (22) having a proximal end for attachment to a hull (12) of the watercraft (10) with an upper articulation (30), and a distal end supporting a hydrofoil, wherein: - said upper articulation (30) is arranged to allow the raising and the lowering of the strut (22) around a strut rotation axis (R1) which is parallel to the longitudinal direction of the watercraft (10), - said assembly further comprising a first control system (34) for controlling said upper articulation (30) for raising and lowering of the strut (22) between at least a deployed position, forming a low position during foil- borne operation of the watercraft (10), and a retracted position, forming an upper position during a hull-borne operation of the watercraft (10).

Description

Hydrofoil assembly for a watercraft with articulated strut and watercraft with said hydrofoil assembly

Technical domain

[0001] The present invention relates to the field of watercraft. More specifically, the invention relates to the field of boats equipped with submerged foils, in particular to hydrofoil watercrafts.

[0002] More precisely, the present invention relates to the means for supporting and articulating submerged foils or hydrofoils, and more generally appendages. The submerged foils or underwater foils are parts located under the structure of the watercraft during its operation. Almost all boats have one or more appendages at the rear for steering, the rudder(s). Foiling boats have also appendages designated foils. Foils might or not be combined with the rudder. The foils are usually designed with a strut, usually a vertical structure, and a wing, usually horizontal. The strut is either partly submerged or not submerged, and is designed to transmit vertical and horizontal loads to the boat. The wing is partly or fully submerged, and is designed to generate a lift force. A foil can include a rudder blade or rudder flaps as part of its strut, to provide steering, i.e., enable the control of the watercraft direction. The foil wing changes its incidence angle or a flap angle to modify the lift provided to the craft. To provide a balanced lift force, the foils are distributed along the longitudinal direction of the boat. The conventional configuration is one foil combined with the rudder(s) and one or more in front of the center-of- mass of the craft.

[0003] These appendages of watercrafts are generally comprising an articulated strut assembly, in order to move up and down the appendage. In case the appendage has a foil in the form of a profiled wing, the appendage can be equipped with another articulation at the free end of the strut, enabling to adapt the orientation of the foil with respect to the strut. [0004] A load-bearing wing or hydrofoil is a device capable of raising a floating member, also referred to below as a hull, of a watercraft partly or wholly out of the water under one effect of hydrodynamic lift generated on its load-bearing plane by the speed at which the watercraft moves. Because lift is transferred from the hull to the load-bearing plane of the load-bearing wing this device thus makes it possible to reduce drag, that is to say reduce the contact friction between the watercraft and the water, in particular waves. The reduction in drag then makes it possible to reduce the power necessary to achieve a high cruising speed, and therefore to make substantial savings, in particular in terms of fuel consumption. Hydrofoil are particularly suitable for all watercrafts, particularly motorboats of small size, powerboats or even luxury vessels such as, by way of non-limiting examples, yachts. In principle they can be fitted to all kinds of sailing and/or motorboats, single or multihulls including motor-driven watercrafts.

[0005] The present invention relates to a hydrofoil assembly for a watercraft comprising a strut having a proximal end for attachment to a hull of the watercraft with an upper articulation, and a distal end supporting a foil wing. The present invention also relates to a watercraft equipped with such a hydrofoil assembly.

Related art

[0006] Because the large dimensions of hydrofoil assemblies can make docking particularly challenging or impossible, solutions for retracting them to reduce their draft have been proposed. With such a possibility, the draught of the watercraft, particularly for coming alongside the shore, or in shallow water, is reduced and, moreover, the hydrofoil watercrafts can be cleaned or repaired without need for dry-docking or putting the watercraft ashore.

[0007] Document WO2012021941 A1 discloses a hydrofoil assembly for a waterborne vessel, comprising a body and a hydrofoil mounted to the body. The hydrofoil is adjustable to vary its lift characteristics. The hydrofoil assembly also comprises a control mechanism operative to control the adjustment of the hydrofoil assembly relative to the support. In this arrangement, the body supporting the hydrofoil is slidably movable with respect to the hull via a support. The hydrofoil is pivotally attached to the body and the control mechanism is operative so as to can provide downward force to the hydrofoil to change the incidence of the hydrofoil relative to the body to create lift. With such an arrangement, the wing forming the hydrofoil always stays under the water level, during both hull- borne and foil-borne modes, which require regular and cumbersome cleaning operation of the hydrofoil to keep good operating conditions of the hydrofoil.

[0008] Document WO2022019764 relates to a safety strut assembly for a hydrofoil craft comprising a strut, which is attached to the hull of the craft by means of a transverse oriented strut axle for pivotal movement with respect to the hull, the assembly further comprising: a control rod passing down through the strut; a linear actuator assembly; a hydrofoil pivotally mounted to the bottom portion of the strut about a transverse oriented foil axle. The use of a transverse-oriented strut axle for pivotal movement with respect to the hull brings some drawback. This requires a stop and locking system for blocking the strut in its vertical position for foil-borne mode in order to prevent any risk for the strut to pivot backward. This also leads to a longitudinal oriented foil to have the foil put aside when the strut is in its retracted horizontal position. With such a configuration, some advantages of longitudinal oriented foil axle are not possible.

[0009] Also, documents US3613622 and WO2016034814 present retractable wings or hydrofoils equipping a watercraft, with an articulated connection between the strut supporting the hydrofoil and the hull, this articulated connection having a degree of freedom in rotation about a transversal axis with respect to the watercraft's hull.

[0010] Documents US6499419B1 and JPS4216496Y1 concern foldable wings or hydrofoils equipping a watercraft, with an upper articulated connection between the strut supporting the hydrofoil and the hull, and a lower articulated connection between the strut and the hydrofoil. These upper and lower articulated connections have a degree of freedom in rotation about a longitudinal axis with respect to the watercraft's hull. [0011] These solutions of the prior art are unsatisfactory. In fact, although they make it possible to fold a load-bearing wing or hydrofoil assemblies, these solutions require modification of the watercraft's hull and are not appropriate for some wing configurations.

[0012] Document EP4177143 discloses and hydrofoil assembly and a watercraft comprising such an assembly solving, at least partially, all of the above shortcomings, by providing an hydrofoil assembly comprising a strut attached at a proximal end to a watercraft hull by a hinge mechanism, so- called canting mechanism, with a pivotal axis substantially parallel to a stern-bow direction of the hull, enabling the strut to be rotated between and upward position and a downward position by a 180° rotation. A wing is pivotably connected at a distal end of the strut and comprise a second canting mechanism providing a control of a canting angle of the wing relative to the strut at least between a horizontal position, wherein the wing is perpendicular to the strut, and a vertical position where the wing is parallel to the strut. In a downward position of the strut, called unfolded, the wing is submerged in the water providing a capability of foiling navigation, in an upward position of the strut, called folded, the wing and the strut are out of the water thus reducing the draught of the watercraft to the draught of the hull, in such a configuration further pivoting the wing in a parallel to the strut configuration considerably reduce the overall width of the watercraft, this configuration being particularly suited for docking.

Short disclosure of the invention

[0013] The instant invention is an improvement of the device disclosed in EP4177143 aiming at providing an improved canting control mechanism of the hydrofoil assembly.

[0014] According to the invention, these aims are attained by the object of the attached claims, and especially by a hydrofoil assembly for a watercraft comprising a strut having a proximal end for attachment to a hull of the watercraft with an upper articulation (also designated "cant"), and a distal end supporting a hydrofoil, wherein: - said upper articulation is arranged to allows the raising and the lowering of the strut around a strut rotation axis which is parallel to the longitudinal direction of the watercraft, said upper articulation comprising a pivot joint aligned with said strut rotation axis,

- said assembly further comprising a first control system for controlling said upper articulation for raising and lowering of the strut between at least a deployed position, forming a low position during foil-borne operation of the watercraft, and an retracted position, forming an upper position during a hull-borne operation of the watercraft, wherein said first control system comprises two actuating devices able to raise the strut, a first actuating device being able to raise the strut between said low deployed position and an intermediate position and a second actuating device being able to raise the strut between said intermediate position and said upper retracted position.

[0015] The use of two different actuating devices used to raise (and to lower) the strut between its deployed, low position, and its retracted, high position, provides better control of the movement of the strut, optimizing the forces required and also facilitates the blocking of the angular position of the strut with respect to the hull in an intermediate position.

[0016] In some embodiments, the hydrofoil assembly further comprises strut locking device able to lock the position of the strut. This secures the position of the strut after the first control system has placed the upper articulation in the required position. One or several of the following provisions are possible. This strut locking device can be able to lock the position of the strut in said deployed position or strut low position: this prevents any uncontrolled change of orientation of the strut during the foil-borne mode of the watercraft. This strut locking device can be able to lock the position of the strut in said retracted position or upper position of the strut: this prevents any uncontrolled change of orientation of the strut during mooring, avoiding potential damage of the strut assembly with the mooring equipment in the harbor or any physical injury with the dock personnel. This strut locking device can be able to lock the position of the strut in at least one intermediate position between said deployed position and said retracted position, including one intermediate low position between said deployed position and a horizontal position of the strut. In such an intermediate low position, the wing is at a height below the upper articulation and can be submerged for operation in a foil-borne mode: in case there are two hydrofoil assemblies respectively equipping both sides of the hull, the two wings are separated from each other with a larger distance with respect to struts being in low position. Such a configuration can be used for operation a watercraft in a rough/stormy sea or water. Also, such a configuration with broad distance between the wings at the distal ends of the struts reduces the force of drag of the front hydrofoil assemblies and thereby reduces the perturbation on a rear hydrofoil assembly.

[0017] In the illustrated hydrofoil assembly, it further comprises a lower articulation (also designated "tilt") between said distal end of said strut and said hydrofoil, wherein said hydrofoil is a monobloc wing defining a load-bearing plane and a span line extending between two wing tips, said span line of the wing being orthogonal to said longitudinal direction of the watercraft, said monobloc wing being connected by its central part to said distal end of said strut by said lower articulation.

In the illustrated hydrofoil assembly, the central part of the wing, which is connected to the strut by the lower articulation, is located at the middle of the span line, at equal distance from the two wing tips. In other embodiments, the wing is not attached symmetrically with respect to the strut by the lower articulation, but the wing is attached asymmetrically to the lower articulation, by a central part closer to one wing tip with respect to the other wing tip. Thus, the hydrofoil assembly further comprises a second control system for controlling said lower articulation.

[0018] According to the invention, a lower articulation as indicated in any passage of the present text, can be combined with an upper articulation as defined in claim 1.

[0019] According to the invention, the lower articulation as described in the following detailed description and according to the specific technical provisions indicated in the present text as part of the technical contribution of the Applicant, can be combined with an upper articulation as in the following definition. Such an upper articulation is arranged to allows the raising and the lowering of the strut around a strut rotation axis which is parallel to the longitudinal direction of the watercraft, said upper articulation comprising a pivot joint aligned with said strut rotation axis, said upper articulation being controlled by a first control system for raising and lowering of the strut between at least a deployed position, forming a low position during foil-borne operation of the watercraft, and a retracted position, forming an upper position during a hull-borne operation of the watercraft.

[0020] The invention also concerns a watercraft comprising a hull and at least one hydrofoil assembly as defined in the present text.

[0021] According to a possible aspect of the invention, the watercraft comprises at least two hydrofoil assemblies as defined in the present text, said hydrofoil assemblies being mounted to both sides of the hull in the half longitudinal portion of the hull comprising the bow. This is a watercraft configuration with two hydrofoil assemblies at the front of the watercraft.

[0022] According to another possible aspect of the invention, the watercraft comprises one hydrofoil assembly as defined in the present text, wherein said hydrofoil assembly is mounted to the rear portion of the hull comprising the stern. This is a watercraft configuration with a hydrofoil assembly at the back of the watercraft.

Short description of the drawings

[0023] Exemplary embodiments of the invention are disclosed in the description and illustrated by the drawings in which:

Figure 1 shows a starboard perspective view of a watercraft from its bow, with a hydrofoil assembly according to the invention located at the half front portion of the watercraft, with the strut of the hydrofoil assembly in its deployed, low position; Figures 2a and 2b are the same views of the watercraft of figure 1, with the strut of the hydrofoil assembly respectively in an intermediate horizontal position and in a retracted, upper position;

Figure 2c shows the same view of the watercraft of figure 1 , with the strut of the hydrofoil assembly respectively in an intermediate low position between said deployed position and a intermediate horizontal position of the strut, the wing being horizontal, for possible foil-borne mode;

Figure 3a shows a simplified side perspective view of the hydrofoil assembly according to the invention, with the strut of the hydrofoil assembly in its low, deployed position, without any covering or hull's part, the strut being downward vertically orientated and the wing being in its first position, horizontally orientated;

Figure 3b and 3c are the same view than figure 3a, the strut of the hydrofoil assembly in its low, deployed position, and the wing having rotated respectively of an acute angle (intermediate position between a first wing position and a second wing position) and of a right angle (second wing position);

Figure 4a is a projection view of the hydrofoil assembly of figure 3a along the IVA direction which is parallel to the wing axis of rotation;

Figure 4b is a projection view of the hydrofoil assembly of figure 3a along the IVB direction which is parallel to the wing span line, perpendicular to the wing axis of rotation and perpendicular to the strut longitudinal direction;

Figure 4c is an enlarged view of the hydrofoil assembly of figure 3a along the IVB direction; Figure 4d is an enlarged view of the hydrofoil assembly of figure 3a, with view by transparency of the arrangement of the lower articulation and of the complementary lower articulation;

Figure 4e is a partial view of figured with a different pitch angle of the wing; and

Figure 4f is a enlarged view of Figure 4a, showing by transparency the arrangement of the lower articulation.

Examples of embodiments of the present invention

[0024] In the present text, the expression "longitudinal direction of the watercraft" means the direction from bow to stern of the boat, or inversely. Also, in the present text, the expression "transversal direction of the watercraft" means the direction from starboard to port side of the boat, or inversely.

[0025] In the present text, the terms "horizontal", "vertical" relate to orientations with respect to the horizon line, unless otherwise expressed. It means that these terms "horizontal", "vertical" relate to orientations of the hydrofoil or wing when the watercraft is at a position on water without pitch, roll nor yawn (namely pitch, roll and yawn angles are zero).

[0026] In the present text, the terms "connected", "fixed" or "attached" means directly or indirectly joined or bound via a mechanical link.

[0027] With reference to figure 1, is shown an embodiment of a watercraft 10 viewed in perspective from the bow 10a. The stern 10b is equipped with a rear appendage14 formed by a rudder with a rudder blade. On both sides of the hull 12, in the front part of the watercraft 10, is attached a hydrofoil assembly 20 according to the invention, namely a hydrofoil assembly 20 at the portside 10c (not visible on Figure 1) and a hydrofoil assembly 20 at the starboard 10d (visible on Figure 1). [0028] The longitudinal direction L of the watercraft 10 extends from the bow 10a to the stern 10b (or inversely), is orthogonal to the transversal direction T of the watercraft 10 which extends from the portside 10c to the starboard 10d (or inversely). The height direction H of the watercraft 10 extends from the bottom part to the roof 16 of the watercraft 10, and is orthogonal to the longitudinal direction L and to the transversal direction T of the watercraft 10.

[0029] The hydrofoil assembly 20 comprises a strut 22 having a proximal end 22a for attachment to the hull 12 of the watercraft with an upper articulation 30, and a distal end 22b supporting a hydrofoil formed by a monobloc wing 24 orientable with respect to the strut through a lower articulation 40 and with a complementary articulation 50 (see figures 4d and 4e).

[0030] In figure 1, the hydrofoil assembly 20 is in a configuration convenient for foil-borne mode. More precisely the strut 22 is in low position or deployed position, and the wing 24 is in horizontal position. In this low position or deployed position of the strut 22, the strut 22 is close to a vertical orientation, so that the wing 24 and the strut 20 are nearly perpendicular to each other.

[0031] In the present text "close to a direction" or "nearly perpendicular" means exactly or almost in a range of angular variation comprised between- 15 degrees and + 15 degrees with respect to the exact mentioned position.

[0032] In figure 2a, the hydrofoil assembly 20 is in a configuration where the watercraft 10 is not operable in foil-borne modes, where it can be operable in hull-borne mode, and that generally corresponds to a temporary configuration before or after a configuration as in figure 1, figure 2b or figure 2c. More precisely, the strut 22 is in any intermediate position, and the wing 24 is in horizontal position. In this intermediate position of the strut 22, the strut 22 is close to a horizontal orientation, so that the wing 24 and the strut 20 are nearly parallel to each other. The passage from the configuration of figure 1 to the configuration of figure 2a results from the rotation of the strut 22 around a strut rotation axis R1 as shown by arrow A1 in figure 2a, and from the rotation of the wing 24 around a wing rotation axis R2 which is perpendicular to the longitudinal direction of the strut 22 and which is parallel to the longitudinal direction L of the watercraft 10. In this intermediate position, the wing 24 is out of the water or almost out of the water.

[0033] In figure 2b, the hydrofoil assembly 20 is in a configuration where the watercraft 10 is not operable in foil-borne mode, where it can be operable in hull-borne mode, and that also corresponds to a configuration before, after or during mooring as disclosed in document EP4177143. More precisely the strut 22 is in retracted position, forming an upper position, and the wing 24 is in a position close to a parallel orientation with respect to the strut 22. In this upper position, the strut 22 is close to a vertical orientation, so that the wing 24 is also close to a vertical orientation and located above the upper articulation 30. The passage from the configuration of figure 1 to the configuration of figure 2b (with passage in the intermediate position of figure 2a) results from the rotation of the strut 22 around the strut rotation axis R1 as shown by arrow A2 in figure 2b, and from the rotation of the wing 24 around the wing rotation axis R2 . In this upper position, the wing 24 is usually out of the water, or in some cases almost out of the water. More generally, in this upper position, the wing 24 defines an angle from 1° to 60° with respect to the strut 22, preferably an angle from 1° to 45°, and more preferably an angle from 1 ° to 30°, considering the half portion of the wing 24 which is the closest with respect to the strut 22 and considering the longitudinal central line or chord of the wing 24 and of the strut 22.

[0034] In this upper, retracted, position of the strut 22, the cleaning of the wing 24 will be very easy and rapid since the wing 24 is generally out of the water. In the illustrated hydrofoil assembly, the wing 24 can be rotated around the rotation axis R2 thanks to the lower articulation 40, with an immobile and retracted strut 22 (upper position of the strut 22).

[0035] In figure 2c, the hydrofoil assembly 20 is in a configuration where the watercraft 10 is also operable in foil-borne mode. More precisely the strut 22 is in an intermediate low position between said deployed position and a horizontal position of the strut 22, and the wing 24 is in horizontal position. In this intermediate low position, the strut 22 is inclined but close to a vertical orientation, so that the wing 24 is submerged, being at a height below the upper articulation 30. The passage from the configuration of figure 1 to the configuration of figure 2c results from the rotation of the strut 22 around the strut rotation axis R1 as shown by arrow A3 in figure 2c, and from the rotation of the wing 24 around the wing rotation axis R2 about the same value of angle, in the inverse direction of rotation to keep the wing in a horizontal position. The value of the angle for passage of the strut 22 from its deployed position or low position (figure 1) to its intermediate low position (figure 2c) can be from 2° to 60°, from 2° to 45°, or from 2° to 30°.

[0036] The second hydrofoil assembly mounted on the hull's other side (port side 10c) and not visible in figures 1, 2a, 2b and 2c is the same as the first hydrofoil assembly 20 visible in figures 1, 2a, 2b and 2c on the starboard side 10d of the watercraft, but is symmetrical with respect to the sagittal plane of the watercraft 20. Then, during the raising of the strut 22 of the first hydrofoil assembly 20 located on the starboard side 10d of the watercraft, the strut 22 rotates clockwise around the strut rotation axis R1, when viewed from the bow 10a as shown in figures 1, 2a, 2b and 2c : this applies for the arrow A1 in figure 2a showing the change of configuration of the first hydrofoil assembly 20 from the low position or deployed position to the intermediate position, for the arrow A2 in figure 2b showing the change of configuration of the first hydrofoil assembly 20 from the low position or deployed position to the retracted position or upper position, and for the arrow A3 in figure 2c showing the change of configuration of the first hydrofoil assembly 20 from the low position or deployed position to an intermediate low position , those arrows A1, A2 and A3 turning clockwise when viewed from the bow 10a. So, symmetrically during the raising of the strut 22 of the second hydrofoil assembly 20 located on the port side 10c of the watercraft, the strut 22 rotates anti-clockwise when viewed from the bow 10a (not shown in figures).

[0037] Also, when viewed from the bow 10a as shown in figures 1, 2a, 2b and 2c, when the strut 22 of the first hydrofoil assembly 20 located on the starboard side 10d of the watercraft, rotates clockwise around the strut rotation axis R1 for a raising motion from the low position or deployed position to the intermediate position (figure 2a), or for a raising motion from the low position or deployed position to a intermediate low position (figure 2c). In those cases, to keep the wing 24 in a horizontal position or close to a horizontal position, the wing 24 rotates anticlockwise around the wing rotation axis R2 of the same angle value (for instance 15°, more generally between 2° to 45°) as the rotation angle value of the strut 22, in an inversed direction. Such change of position of the wing 24 with respect to the strut 22 is visible in figure 3b (arrows B1).

[0038] Operation modes of the arrangement described hereinabove are disclosed in document EP4177143.

[0039] The expression "the wing 24 is orthogonal with respect to the strut 22" means the span line S of the wing is orthogonal to the longitudinal direction of the strut 22. In that configuration, the hydrofoil assembly 20 as an inverted-T shape.

[0040] As shown in Figure 3c, with a bigger angle of rotation of the wing 24 around the wing rotation axis R2 (arrows B2), the wing 24 comes parallel to the strut 22 (position 24"). This situation can occur in the intermediate position of the strut 22 (figure 2a). This situation is implemented when placing the strut 22 in the upper position (figure 2b) either for hull-borne operation of the watercraft or for mooring.

[0041] A possible embodiment for the upper articulation 30 will now be described with reference to figures 3a, 3b, 3c, 4a, 4b, 4c, 4dand 4f. This upper articulation 30 comprises a pivot joint 32 aligned with said strut rotation axis R1. Said pivot joint 32 comprises a bearing 32a receiving a shaft 32b, the shaft 32b being able to rotate with respect to the bearing 32a around said strut rotation axis R1, one among the bearing 32a and shaft 32b being linked to the hull 12 and the other one among the bearing 32a and the shaft 32b being linked to the strut 22. The adjective "linked" means directly linked without intermediate part(s) or indirectly linked with intermediate part(s). As a possible implementation, the proximal end 22a of the strut 22 is attached to a bearing 32a cooperating in rotation with a shaft 32b integral with a end plate fixed to the hull 12.

[0042] To control the angular orientation of the strut 22 with respect to the hull 12, the upper articulation 30 of the hydrofoil assembly 20 comprises a first control system 34. This first control system 34 can be implemented in several ways. In possible embodiments, this first control system 34 comprises two actuating devices able to raise and to lower the strut 22, a first actuating device 36 being able to raise the strut between said low deployed position and an intermediate position and a second actuating device 37 being able to raise the strut between said intermediate position and said upper retracted position. In possible embodiments not shown in the figures, said actuating devices comprise a linear actuator such as a linear motor. In possible embodiments, said actuating devices comprise a cylinder as in the illustrated embodiment. More precisely, in the illustrated embodiment of the first control system 34, there is a first actuating device comprising a first cylinder 36 and there is a second actuating device comprising a second cylinder 37. In the illustrated embodiment of the first control system 34, said first cylinder 36 and said second cylinder 37 have a first end fixedly attached to an element immobile with respect to the hull 12 of the watercraft 20, and a second end attached to an element immobile and fixed with respect to the strut 22.

[0043] As visible in figures 3a, 3b, 3c, 4a, 4b, 4c, 4d, 4e and 4f, this element immobile and fixed with respect to the strut 22 is a strut extension part 35 having a bar shape, this elongated element having a longitudinal direction perpendicular to the strut 22 and parallel to the wing rotation axis R2. The second end of the first cylinder 36 is attached with a first pivoting link to the strut extension part 35 and the second end of the second cylinder 37 is attached with a second pivoting link to the strut extension part 35. When in deployed, low position, of the strut 22, the first end and the second end of the first cylinder 36 are aligned in a direction close to the horizontal direction (see figures 4d and 4f). Also, when in deployed, low position, of the strut 22, the first end and the second end of the second cylinder 37 are aligned in an inclined direction where the first end is higher than the second end (see figures 4d and 4f). With this configuration, the raising of the strut 22 from its low deployed position (figure 1) and its intermediate position (figure 2a - strut is in horizontal position) is possible via the activation of the first cylinder 36 (first actuating device) which rod extension out of the cylinder body is growing so that the first cylinder 36 pushes the strut extension part 35 further away from the hull 12. For further raising of the strut 22 from the intermediate position (figure 2a) to a higher position, including the retracted, upper position of figure 2b, the second cylinder 37 (second actuating device (37) is activated so that its rod extension out of the cylinder body is reduced so that the first cylinder 36 pulls the strut extension part 35 which that comes closer the hull 12, above the strut rotation axis R1.

[0044] Said first cylinder 36 and said second cylinder 37 can be hydraulic cylinders or pneumatic cylinders or electric cylinders.

[0045] In other possible embodiments, actuating devices able to raise/lower the strut 22 comprise a linear actuator, such as an electric rotary motor or a linear motor.

[0046] In a preferred embodiment, the hydrofoil assembly may comprise a strut locking device able to lock the position of the strut in at least one intermediate position between said deployed position and said retracted position, including one intermediate low position between said deployed position and a horizontal position of the strut.

[0047] In the illustrated embodiment, all these above provisions regarding a strut locking device are present since it is possible to lock the extension position of the cylinder rod with respect to the cylinder body of the first cylinder 36 and of the second cylinder 37 to block the angular position of the strut 22 with respect to the hull 12. In hydraulic cylinders 36, 37, the locking of the extension position of the rod (corresponding to activation of strut locking device) can be implemented by closing a valve. In presence of linear actuators, notably electric linear actuators, or linear motor as actuating device being able to raise and lower the strut 24 (to control the position of the strut), the activation of strut locking device can be implemented via irreversible electric cylinders with a driving ballscrew. [0048] In a possible embodiment, said strut locking device allows the removable attachment of the strut 22 with respect to the hull 12 in the deployed position of the strut 12, wherein activation of said strut locking device results in a deployed and locked position of the strut 22.

For instance, said second control system can change the orientation of the monobloc wing 24 with respect to the strut 22, in said deployed and locked position of the strut 22.

[0049] The lower articulation 40 of the illustrated hydrofoil assembly will now be described with reference to figures 3a, 3b, 3c, 4a, 4b, 4c, 4d, 4e and 4f. The wing 24 is articulated by its central portion to the distal end 22b of the strut 22 by the lower articulation 40.

[0050] The lower articulation 40 is arranged for enabling a load-bearing plane P to rotate around the wing rotation axis R2 which is perpendicular to the longitudinal direction of the strut 22 and which is parallel to the longitudinal direction L of the watercraft, from a first wing position 24' where a span line S is orthogonal to said strut 22 (figures 1, 3a, 4a, 4b, 4c, 4d, and 4e) to a second wing position 24" where the span line S is parallel to said strut 22 (figures 2b, 3c and 4f), and inversely (see figures 3c and 4f to have both first wing position 24' and second wing position 24" represented).

[0051] The hydrofoil assembly 20 of the illustrated hydrofoil assembly comprises a second control system 44 for controlling said lower articulation 40. This first control system 44 can be implemented in several ways. In the illustrated embodiment, the lower articulation 40 and said second control system 44 enable pivoting of said monobloc wing 24 around said wing rotation axis R2 between said first wing position 24' and said second wing position 24" of said load bearing plane P of the monobloc wing 24, wherein the monobloc wing 24 rotates at least up to 90° and preferably up to 150° with respect to the strut 22, between said wing first position 24' and said wing second position 24". Thus, it is understood that the lower articulation 40 can be activated (rotation of the wing 24 around the wing rotation axis R2), independently of the upper joint 30 (rotation of the support 22 around the strut rotation axis R1 [0052] In the illustrated hydrofoil assembly, the second control system 44 comprises a crankshaft system 42 with a rotating shaft 47 in the form of a bulb in said lower articulation 40, said rotating shaft 47 is fixed to the monobloc wing 24. Said rotating shaft 47 is concentric with the wing rotation axis R2. More precisely, the bulb forming the rotating shaft 47 has a transversal aperture 47a accommodating the monobloc wing 24. Also, the second control system 44 comprises a linear actuator, said linear actuator having a mobile portion sliding 45 along the longitudinal direction of the strut 22 (see figures 4d and 4f).

[0053] According to the technical contribution of the Applicant, the lower articulation 40 further comprises a cam 46 or eccentric arm with a first extremity connected to said mobile portion 45 and with a second extremity connected to the rotating shaft 47 at a distance of the axis of rotation of the rotating shaft 47 (see figures 4d and 4f). In the hydrofoil assembly, as shown in the figures, this axis of rotation of the rotating shaft 47 is identical to the wing rotation axis R2.

[0054] In the illustrated hydrofoil assembly, the linear actuator of the second control system 44 has a mobile sliding portion 45 at least partially located inside the strut 22 (see figures 4c, 4d, and 4f).

This mobile sliding portion 45 has an end connected to a pivot joint 42 which pivoting axis is parallel to the wing rotation axis R2. According to the technical contribution of the Applicant, this pivot joint 42 is connected to the first end of the eccentric 46 or eccentric arm forming a cam to change the sliding motion of the mobile portion 45 into a rotating motion. According to the technical contribution of the Applicant, this eccentric 46 has the shape of a finger where the main plane of the finger is orthogonal to the wing rotation axis R2 and where the finger is not secant with the wing rotation axis R2.

[0055] According to the technical contribution of the Applicant, the lower articulation 40 further comprises an elongated sleeve 48 which main direction is perpendicular to the longitudinal direction of the strut 22 and to the longitudinal direction of the wing 24 (see figures 4c and 4d). According to the technical contribution of the Applicant, the rotating shaft 47 is divided up into two attached portions , where a first portion 47b is rotatably accommodated with respect to said sleeve 48 and a second portion 47c supports the monobloc wing 24, the latter being accommodated in an aperture 47a passing through the second portion 47c. Preferably, according to the technical contribution of the Applicant, the longitudinal projection of the distal end of the strut 22 is at least partially located between said first portion 47b of the rotating shaft and said second portion 47c of the rotating shaft 47.

According to the technical contribution of the Applicant, the second extremity of the eccentric arm 46 is fixedly connected to the first portion 47b of the rotating shaft 47 at a distance of the axis of rotation of the rotating shaft 47 , so that the sliding motion of the mobile portion 45 is changed into a rotation of the rotating shaft 47, thereby changing the angular position of the wing 24 with respect to the strut 22.

[0056] As illustrated, and according to the technical contribution of the Applicant, the elongated sleeve 48 forms a bearing supporting the rotating shaft 47. Moreover, this elongated sleeve 48 is immobile with respect to the strut 22.

[0057] As a possible implementation, and according to the technical contribution of the Applicant, said linear actuator of the second control system 44 can be a hydraulic cylinder or a pneumatic cylinder or an electric cylinder, wherein said cylinder comprises a cylinder barrel, and a piston connected to a piston rod moving back and forth in said cylinder barrel, said piston rod forming said mobile portion 45 or being extended by said mobile portion 45.

[0058] In some possible implementations, and according to the technical contribution of the Applicant, the hydrofoil assembly further comprises a wing locking device according to any of the following provisions. This wing locking device is able to lock the angular position of the wing. This secures the position of the wing after the second control system has placed the upper articulation in the required position. One or several of the following provisions are possible.

This wing locking device is able to lock the position of the wing 24 in at least the following positions : in said first wing position 24' where the span line S is orthogonal to said strut 22, and in said second wing position 24" where the span line is parallel to said strut 22.

This wing locking device is further able to lock the position of the wing 24 in an intermediate wing position where the acute angle between the strut 22 and the vertical direction, when the wing 24 is at a height below the upper articulation 30, is equal to the acute angle between the strut 22 and the projection of the axis orthogonal to the span line S of the wing 24, said projection being taken in a vertical plane orthogonal to the longitudinal direction L of the watercraft. This provision allows to keep the wing 24 horizontal with an inclined strut 22, notably with a strut 22 in an intermediate low position. Preferably, in said intermediate wing position said acute angle between the strut 24 and the vertical direction is equal to an angle between 2 degrees and 60 degrees, and more preferably between 2 degrees and 45 degrees.

According to a possibility, said lower articulation, second control system and said wing locking device enable pivoting and locking of the angular position of said monobloc wing 24 between any intermediate position between said first wing position 24' and said second wing position 24 ". When the linear actuator of the second control system is a pneumatic cylinder, this wing locking device can be a valve which closing lock the wing position and which opening allows a change in the wing angular position with respect to the strut.

[0059] Preferably, in the hydrofoil assembly, the control of the lower articulation 40 is independent from the control of the upper articulation 30. This means that one can adapt the position of the wing 24, namely its angular orientation with respect to the strut 22, in all possible positions (from a perpendicular respective position to a parallel respective position), whatever is the angular position of the strut 22 with respect to the hull 12 (in the low position or deployed position of figure 1, in the intermediate position of figure 2a, in an intermediate low position as in figure 2c or in the retracted position -upper position- of figure 2b).

[0060] In particular, the first control system 34 for controlling said upper articulation 30 for raising and lowering of the strut 22 by rotation of the strut 22 around the strut rotation axis R1 is separated from the second control system 44 for controlling said lower articulation 40 which allows a rotation of the hydrofoil or wing 24 around the wing rotation axis R2. [0061] Preferably, as shown in the figures of the illustrated hydrofoil assembly, the wing rotation axis R2 and the strut rotation axis R1 are parallel to each other.

[0062] Generally, both struts 22 respectively on the portside 10c and starboard 10d, are moved at the same time, in parallel, and according to the same rotating motion around strut rotation axis R1 (considering a relative symmetric position of the two struts 22 on both sides of a sagittal plane of the water craft parallel to the longitudinal direction L and transversal direction T).

In the same way, generally both wings 24 are rotated at the same time, in parallel, and according to the same rotating motion around wing rotation axis R2 (considering a relative symmetric position of the two wings 24 on both sides of the sagittal plane).

It means the two struts 22 on one side, and the two wings 24 on the other side (or only the two struts 22 or only the two wings 24) are rotating in the same angle value but in opposite directions.

[0063] Also, in the illustrated hydrofoil assembly 20, it further comprises a complementary lower articulation 50 between said distal end 22b of said strut 22 and said hydrofoil or wing 24 (figures 4d and 4e). Said complementary lower articulation is arranged for enabling the pivoting of said wing 24 around its span line S which changes the pitch angle between a horizontal plane and the load-bearing plane P, and wherein said hydrofoil assembly further comprising a third control system 54 for controlling said complementary lower articulation 50.

[0064] This third control system 54 comprises a linear actuator. According to the technical contribution of the Applicant, said linear actuator has a mobile portion sliding 55 along the longitudinal direction of the strut 22 up to the internal cavity of the rotating shaft 47 (see figure 4d and 4f). According to the technical contribution of the Applicant, the complementary lower articulation 50 comprises a crankshaft system 52 with several connecting rods able to pivot with respect to each other. According to the technical contribution of the Applicant, this crankshaft system 52 is attached to a tilting portion 47d of the second portion 47c of the rotating shaft. According to the technical contribution of the Applicant, the crankshaft system 52 and tilting portion 47d are arranged so that the sliding motion of the mobile portion 55 along a direction parallel to the strut 22 makes the tilting portion 47d to tilt around an axis parallel to the wing 24, changing thereby the pitch angle of the wing 24. [0065] According to the technical contribution of the Applicant, to prevent a too important change of angle of rotation of the wing around its wing rotation axis R2, the rotation of the rotating shaft 47 can be limited by a stop portion. In a possible variant of the illustrated hydrofoil assembly, this stop portion can be an aperture in the first portion 47b of the rotating shaft 47, through which passes the mobile portion 55 or a portion of the crankshaft system 52. When the rotating shaft 47 rotates, there is a limit position where the mobile portion 55 or a rod of the crankshaft system 52 or a hollow part surrounding and protecting those latter, abuts against the edge of the aperture forming the stop portion.

Reference signs used in the figures Watercraft a Bow b Stern c Portside d Starboard Hull Rear appendage Roof Hydrofoil assembly Strut a Proximal end of the strut b Distal end of the strut Wing (hydrofoil) a Tip of the wing b Tip of the wing c Lower face of the wing (Load bearing plane P) ' Wing first position " Wing second position Upper articulation Pivot joint a Bearing b Shaft First control system Strut extension part (bar) First cylinder (first actuating device) Second cylinder (second actuating device) 40 Lower articulation

42 Pivot joint (Crankshaft system)

44 Second control system

45 Mobile portion of linear actuator = sliding part

46 Excentric arm or cam

47 Rotating shaft (bulb of the hydrofoil)

47a Aperture accommodating the central portion of the wing

47b Second portion

47c Third portion

50 Complementary lower articulation

52 Crankshaft system

54 Third control system

55 Mobile portion of linear actuator = sliding part

L Longitudinal direction of the watercraft 10

T Transversal direction of the watercraft 10

H Height direction of the watercraft 10

R1 Strut rotation axis

R2 Wing rotation axis

A1 Arrow (strut rotation- raising up to an intermediate position)

A2 Arrow (strut rotation- raising up to an upper position)

A3 Arrow (strut rotation- raising up to an intermediate low position)

B1 Arrow (wing rotation - wing position adaptation for foil-borne mode)

B2 Arrow (wing rotation - wing position adaptation for mooring and hull-borne mode)

S Span line

P Load bearing plane

Claims

1. Hydrofoil assembly (20) for a watercraft (10) comprising a strut (22) having a proximal end for attachment to a hull (12) of the watercraft (10) with an upper articulation (30), and a distal end supporting a hydrofoil, wherein:

- said upper articulation (30) is arranged to allow a raising and a lowering of the strut (22) around a strut rotation axis (R1) which is parallel to a longitudinal direction of the watercraft (10), said upper articulation (30) comprising a pivot joint aligned with said strut rotation axis (R1),

- said assembly further comprising a first control system (34) for controlling said upper articulation (30) for raising and lowering of the strut (22) between at least a deployed position, forming a low position during foil- borne operation of the watercraft (10), and a retracted position, forming an upper position during a hull-borne operation of the watercraft (10), wherein said first control system (34) comprises two actuating devices (36, 37) able to raise the strut (22), a first actuating device (36) being able to raise the strut (22) between said low deployed position and an intermediate position and a second actuating device (37) being able to raise the strut (22) between said intermediate position and said upper retracted position.

2. Hydrofoil assembly (20) according to claim 1, wherein said pivot joint comprises a bearing receiving a shaft, the shaft being able to rotate with respect to the bearing around said strut rotation axis (R1), one among the bearing and shaft being linked to the hull (12) and the other one among the bearing and the shaft being linked to the strut (22).

3. Hydrofoil assembly (20) according to claim 1 or 2, wherein said intermediate position is close to a horizontal orientation of the strut (22).

4. Hydrofoil assembly (20) according to any of claims 1 to 3, wherein said actuating devices comprise a linear actuator.

5. Hydrofoil assembly (20) according to any of claims 1 to 4, wherein said actuating devices (36, 37) comprise a cylinder.

6. Hydrofoil assembly (20) according to claim 5, wherein said first actuating device (36) comprises a first cylinder and wherein said second actuating device (37) comprises a second cylinder.

7. Hydrofoil assembly (20) according to claim 6, wherein said first cylinder and said second cylinder are hydraulic cylinders or pneumatic cylinders or electric cylinders.

8. Hydrofoil assembly (20) according to claim 6 or 7, wherein said first cylinder (36) and said second cylinder (37) have a first end attached to an element immobile with respect to the hull (12) of the watercraft (10), and a second end attached to an element immobile with respect to the strut (22).

9. Hydrofoil assembly (20) according to claim 6, wherein said element immobile with respect to the hull (12) of the watercraft (10) is a strut extension part (35), wherein the second end of the first cylinder (36) is attached with a first pivoting link to the strut extension part (35) and the second end of the second cylinder (37) is attached with a second pivoting link to the strut extension part (35), and wherein when the strut (22) is in low deployed position, the first end and the second end of the second cylinder (37) are aligned in an inclined direction where the first end is higher than the second end.

10. Hydrofoil assembly (20) according to claim 9, wherein when the strut (22) is in low deployed position, the first end and the second end of the first cylinder (36) are aligned in a direction close to the horizontal direction.

11. Hydrofoil assembly (20) according to any of claims 1 to 10, wherein said first control system (34) comprises at least one electric actuator.

12. Hydrofoil assembly (20) according to claim 11, wherein said electric actuator is an electric rotary motor or a linear motor.

13. Hydrofoil assembly (20) according to any of claims 1 to 12, wherein it further comprises a strut locking device able to lock the position of the strut (22) in at least one intermediate position between said deployed position and said retracted position, including one intermediate low position between said deployed position and a horizontal position of the strut (22).