Lift-propulsion system for a watercraft and watercraft having same

Abstract

A lift-propulsion assembly and a watercraft. The watercraft includes a buoyant body having upper and lower surfaces on respective upper and lower sides thereof; a lift-propulsion system including a mast connected to the buoyant body, the mast having a proximal end and a distal end, the mast extending from the lower side of the buoyant body; and the lift-propulsion assembly. The assembly includes an assembly frame connected to the distal end of the mast; a propulsion unit for providing thrust to the watercraft, the propulsion unit being connected to the assembly frame; a hydrofoil for providing lift to the watercraft, the hydrofoil being selectively connected to the assembly frame; and a manually-operable attachment system connecting the hydrofoil to the assembly frame.

Description

CROSS-REFERENCE

[0001] The present application claims priority to United States Provisional Patent Application No. 63 / 520,397, entitled "Lift-Propulsion System for a Watercraft and Watercraft Having Same," filed on August 18, 2023, the entirety of which is incorporated by reference herein.FIELD OF TECHNOLOGY

[0002] The present technology relates to lift-propulsion systems for watercraft.BACKGROUND

[0003] Surfboards are sometimes equipped with a hydrofoil to provide lift thereto, notably raising a running surface of the surfboard from the water to reduce drag. In addition to a hydrofoil, surfboards can also be equipped with a propulsion unit which provides thrust to the surfboard and thereby reduces user effort during operation of the surfboard.

[0004] Different sizes and forms of hydrofoil can be used for such surfboards, with different arrangements providing different results. For instance, some hydrofoils may be shaped for stability, providing more ease of use for a new operator. Others may be formed to provide high speed and manoeuvrability, of use to a more advanced operator, while not being stable enough for the new operator. To address this issue, some hydrofoil-equipped surfboards are designed to allow the user to replace one hydrofoil with another. In addition, in some cases, hydrofoils may also be cumbersome during transport. To address this issue, some hydrofoil-equipped surfboards have been designed to be disassembled, for example by disconnecting the mast and hydrofoil from the board, to ease transport.

[0005] However, hydrofoils must be securely connected to the surfboards during use, even through high drag forces while operating in water. As such, even in watercraft designed to be disassembled, this disassembly can be complex and time consuming, require tools, and may also require additional preparation by the user to assemble or disassemble the hydrofoil before using the surfboard.

[0006] While the above issues have been discussed relative to surfboards, this also applies to different types of watercraft that can be outfitted with a hydrofoil and a propulsion unit.

[0007] In view of the foregoing, there is a need for a watercraft with a lift-propulsion system that addresses at least some of these drawbacks.SUMMARY

[0008] It is an object of the present technology to ameliorate at least some of the inconveniences present in the prior art.

[0009] According to an aspect of the present technology, there is provided a watercraft including a buoyant body having upper and lower surfaces on respective upper and lower sides thereof; a lift-propulsion system comprising a mast connected to the buoyant body, the mast having a proximal end and a distal end, the mast extending from the lower side of the buoyant body; and a lift-propulsion assembly comprising an assembly frame connected to the distal end of the mast; a propulsion unit for providing thrust to the watercraft, the propulsion unit being connected to the assembly frame; a hydrofoil for providing lift to the watercraft, the hydrofoil being selectively connected to the assembly frame; and a manually-operable attachment system connecting the hydrofoil to the assembly frame.

[0010] In some embodiments, the assembly frame comprises one of a male tapered portion and a female tapered portion; the hydrofoil comprises an other one of the male tapered portion and the female tapered portion; and the male tapered portion is engaged in the female tapered portion when the hydrofoil is connected to the assembly frame.

[0011] In some embodiments, the male tapered portion and the female tapered portion extend and taper along a longitudinal direction of the watercraft.

[0012] In some embodiments, for each of the male tapered portion and the female tapered portion: a top surface, a bottom surface, and lateral side surfaces taper along the longitudinal direction of the watercraft.

[0013] In some embodiments, the assembly frame comprises the male tapered portion; and the hydrofoil comprises the female tapered portion.

[0014] In some embodiments, the attachment system comprises a rigid connection member connected to a one of the assembly frame and the hydrofoil; and the hydrofoil is selectively maintained connected to the assembly frame at least in part by engagement of the rigid connection member with an other one of the assembly frame and the hydrofoil.

[0015] In some embodiments, the rigid connection member is connected to and extends from the assembly frame; and the hydrofoil is selectively maintained connected to the assembly frame by engagement of the rigid connection member with the hydrofoil.

[0016] In some embodiments, the rigid connection member includes a stem; and a distal end portion connected to the stem, the distal end portion having a greater width than the stem.

[0017] In some embodiments, the attachment system comprises a locking element connected to a one of the assembly frame and the hydrofoil; the locking element is selectively rotatable between a locked position and an unlocked position; and the hydrofoil is selectively maintained connected to the assembly frame at least in part by engagement of the locking element with an other one of the assembly frame and the hydrofoil.

[0018] In some embodiments, the locking element is pivotally connected to the hydrofoil; and the hydrofoil is selectively maintained connected to the assembly frame by engagement of the locking element with the assembly frame.

[0019] In some embodiments, the locking element comprises an element body defining a slot therein, and a handle portion connected to the element body; and the hydrofoil is selectively maintained in connection to the assembly frame by an operator rotating the locking element to the locked position.

[0020] In some embodiments, the handle portion is accessible on a lower side of the hydrofoil.

[0021] In some embodiments, the attachment system comprises: a rigid connection member connected to the assembly frame, and a locking element pivotally connected to the hydrofoil; and the hydrofoil is selectively maintained connected to the assembly frame at least in part by engagement of the locking element with rigid connection member.

[0022] In some embodiments, the locking element comprises: an element body defining a slot therein, and a handle portion connected to the element body; and the rigid connection member comprises a stem, and a distal end portion connected to the stem, the distal end portion having a greater width than the stem.

[0023] In some embodiments, at least a first portion of the slot is wider than a width of the distal end portion, permitting the distal end portion to pass through the first portion; and at least a second portion of the slot, opposite the first portion, is wider than a diameter of the stem and narrower than the width of the distal end portion, preventing the distal end portion from passing through the second portion.

[0024] In some embodiments, the locking element is selectively rotatable between at least an unlocked position and a locked position; in the unlocked position, the first portion of the slot is aligned with the rigid connecting member, such that the hydrofoil is selectively removable from the assembly frame; and in the locked position, with the rigid connecting member being engaged with the locking element, the second portion of the slot is aligned with the rigid connecting member, such that the hydrofoil is prevented from being removed from the assembly frame.

[0025] In some embodiments, the handle portion is accessible on a lower side of the hydrofoil.

[0026] In some embodiments, when the rigid connecting member is inserted in the locking element, the stem passes through the slot.

[0027] In some embodiments, the locking element is rotatable about an axis perpendicular to a bottom surface of the hydrofoil between the locked position and the unlocked position.

[0028] In some embodiments, the lift-propulsion assembly is a retractable lift-propulsion assembly; the mast is movable between a retracted position and a deployed position; the mast extends from the lower side of the buoyant body in the deployed position; and a distance between the distal end of the mast and the lower surface of the buoyant body is greater in the deployed position than in the retracted position.

[0029] In some embodiments, the propulsion unit provides thrust to the watercraft in the retracted and deployed positions of the mast; and the hydrofoil provides lift to the watercraft in at least the deployed position of the mast.

[0030] In some embodiments, the lift-propulsion assembly is connected to the distal end of the mast such that: in the deployed position of the mast, the lift-propulsion assembly is distanced from the buoyant body of the watercraft; and in the retracted position of the mast, the lift-propulsion assembly is proximate the buoyant body of the watercraft.

[0031] In some embodiments, the hydrofoil is a front hydrofoil; and the lift-propulsion assembly further comprises a rear hydrofoil connected to the assembly frame, the rear hydrofoil being disposed rearward of the front hydrofoil when the front hydrofoil is selectively connected to the assembly frame.

[0032] In some embodiments, the lift-propulsion assembly further comprises an electric motor for driving the propulsion unit.

[0033] In some embodiments, the lift-propulsion system further comprises an electrical assembly supported by the buoyant body, the electrical assembly comprising a battery for powering the electric motor; and an inverter in electrical communication between the battery and the electric motor.

[0034] According to an aspect of the present technology, there is provided the propulsion unit comprises one of a propeller and an impeller.

[0035] In some embodiments, the watercraft is a board.

[0036] In some embodiments, the buoyant body is a molded plastic buoyant body.

[0037] According to an aspect of the present technology, there is provided a lift-propulsion system for a watercraft, comprising a mast connected to the buoyant body, the mast having a proximal end and a distal end, the mast extending from the lower side of the buoyant body; and a lift-propulsion assembly comprising an assembly frame connected to the distal end of the mast; a propulsion unit for providing thrust to the watercraft, the propulsion unit being connected to the assembly frame; a hydrofoil for providing lift to the watercraft, the hydrofoil being selectively connected to the assembly frame; and a manually-operable attachment system connecting the hydrofoil to the assembly frame.

[0038] In some embodiments, the assembly frame comprises one of a male tapered portion and a female tapered portion; the hydrofoil comprises an other one of the male tapered portion and the female tapered portion; and the male tapered portion is engaged in the female tapered portion when the hydrofoil is connected to the assembly frame.

[0039] In some embodiments, the male tapered portion and the female tapered portion extend and taper along a longitudinal direction defined by the system.

[0040] In some embodiments, for each of the male tapered portion and the female tapered portion: a top surface, a bottom surface, and lateral side surfaces taper along the longitudinal direction.

[0041] In some embodiments, the assembly frame comprises the male tapered portion; and the hydrofoil comprises the female tapered portion.

[0042] In some embodiments, the attachment system comprises a rigid connection member connected to a one of the assembly frame and the hydrofoil; and the hydrofoil is selectively maintained connected to the assembly frame at least in part by engagement of the rigid connection member with an other one of the assembly frame and the hydrofoil.

[0043] In some embodiments, the rigid connection member is connected to and extends from the assembly frame; and the hydrofoil is selectively maintained connected to the assembly frame by engagement of the rigid connection member with the hydrofoil.

[0044] In some embodiments, the rigid connection member includes a stem; and a distal end portion connected to the stem, the distal end portion having a greater width than the stem.

[0045] In some embodiments, the attachment system comprises a locking element connected to a one of the assembly frame and the hydrofoil; the locking element is selectively rotatable between a locked position and an unlocked position; and the hydrofoil is selectively maintained connected to the assembly frame at least in part by engagement of the locking element with an other one of the assembly frame and the hydrofoil.

[0046] In some embodiments, the locking element is pivotally connected to the hydrofoil; and the hydrofoil is selectively maintained connected to the assembly frame by engagement of the locking element with the assembly frame.

[0047] In some embodiments, the locking element comprises an element body defining a slot therein, and a handle portion connected to the element body; and the hydrofoil is selectively maintained in connection to the assembly frame by an operator rotating the locking element to the locked position.

[0048] In some embodiments, the handle portion is accessible on a lower side of the hydrofoil.

[0049] In some embodiments, the attachment system comprises a rigid connection member connected to the assembly frame, and a locking element pivotally connected to the hydrofoil; and the hydrofoil is selectively maintained connected to the assembly frame at least in part by engagement of the locking element with rigid connection member.

[0050] In some embodiments, the locking element comprises an element body defining a slot therein, and a handle portion connected to the element body; and the rigid connection member comprises a stem, and a distal end portion connected to the stem, the distal end portion having a greater width than the stem.

[0051] In some embodiments, at least a first portion of the slot is wider than a width of the distal end portion, permitting the distal end portion to pass through the first portion; and at least a second portion of the slot, opposite the first portion, is wider than a diameter of the stem and narrower than the width of the distal end portion, preventing the distal end portion from passing through the second portion.

[0052] In some embodiments, the locking element is selectively rotatable between at least an unlocked position and a locked position; in the unlocked position, the first portion of the slot is aligned with the rigid connecting member, such that the hydrofoil is selectively removable from the assembly frame; and in the locked position, with the rigid connecting member being engaged with the locking element, the second portion of the slot is aligned with the rigid connecting member, such that the hydrofoil is prevented from being removed from the assembly frame.

[0053] In some embodiments, the handle portion is accessible on a lower side of the hydrofoil.

[0054] In some embodiments, when the rigid connecting member is inserted in the locking element, the stem passes through the slot.

[0055] In some embodiments, the locking element is rotatable about an axis perpendicular to a bottom surface of the hydrofoil between the locked position and the unlocked position.

[0056] In some embodiments, the lift-propulsion assembly is a retractable lift-propulsion assembly; and the mast is movable between a retracted position and a deployed position.

[0057] In some embodiments, the hydrofoil is a front hydrofoil; and the lift-propulsion assembly further comprises a rear hydrofoil connected to the assembly frame, the rear hydrofoil being disposed rearward of the front hydrofoil when the front hydrofoil is selectively connected to the assembly frame.

[0058] In some embodiments, the lift-propulsion assembly further comprises an electric motor for driving the propulsion unit.

[0059] In some embodiments, the propulsion unit comprises one of a propeller and an impeller.

[0060] Embodiments of the present technology each have at least one of the above-mentioned objects and / or aspects, but do not necessarily have all of them. It should be understood that some aspects of the present technology that have resulted from attempting to attain the above-mentioned objects may not satisfy these objects and / or may satisfy other objects not specifically recited herein.

[0061] Explanations and / or definitions of terms provided in the present application take precedence over explanations and / or definitions of these terms that may be found in any documents incorporated herein by reference.

[0062] Additional and / or alternative features, aspects and advantages of embodiments of the present technology will become apparent from the following description, the accompanying drawings and the appended claims.BRIEF DESCRIPTION OF THE DRAWINGS

[0063] For a better understanding of the present technology, as well as other aspects and further features thereof, reference is made to the following description which is to be used in conjunction with the accompanying drawings, where: Figure 1 is a top, rear, right side perspective view of a watercraft according to a nonlimiting embodiment of the present technology, with a lift-propulsion system of the watercraft in a retracted position; Figure 2 is a bottom, front, right side perspective view of the watercraft of Figure 1, with the lift-propulsion system in the retracted position; Figure 3 is a top plan view of the watercraft of Figure 1, with the lift-propulsion system in the retracted position; Figure 4 is a left side elevation view of the watercraft of Figure 1, with the lift-propulsion system in the retracted position; Figure 5 is a top, rear, right side perspective view of the watercraft of Figure 1, with the lift-propulsion system in a deployed position; Figure 6 is a bottom, front, right side perspective view of the watercraft of Figure 1, with the lift-propulsion system in the deployed position; Figure 7 is a left side elevation view of the watercraft of Figure 1, with the lift-propulsion system in the deployed position; Figure 8 is a bottom, front, left side perspective view of the lift-propulsion system of the watercraft of Figure 1, with the lift-propulsion system in the retracted position; Figure 9 is a top, rear, right side perspective view of a lift-propulsion assembly of the lift-propulsion system of Figure 8; Figure 10 is a partially exploded, top, rear, right side perspective view of the lift-propulsion assembly of Figure 9; Figure 11 is a bottom, front, left side perspective view of the lift-propulsion assembly of Figure 9; Figure 12 is a partially exploded, bottom, front, left side perspective view of the lift-propulsion assembly of Figure 9; Figure 13 is a top plan view of the lift-propulsion assembly of Figure 9; Figure 14 is a cross-sectional view of the lift-propulsion assembly of Figure 9, taken along line 14-14 of Figure 13; Figure 15 is a close-up, cross-sectional view of the lift-propulsion assembly of Figure 9, taken from call-out portion of Figure 14; Figure 16 is a partially exploded, top plan view of the lift-propulsion assembly of Figure 9; Figure 17 is a cross-sectional view of the lift-propulsion assembly of Figure 9, taken along line 17-17 of Figure 16; Figure 18 is a top, rear, right side perspective view of a hydrofoil of the lift-propulsion assembly of Figure 9; Figure 19 is a bottom, rear perspective view of the hydrofoil of Figure 18; Figure 20 is a front elevation view of the hydrofoil of Figure 18; Figure 21 is a top plan view of the hydrofoil of Figure 18; Figure 22 is a top, side perspective view of a locking element of the lift-propulsion assembly of Figure 9; Figure 23 is a bottom, side perspective view of the locking element of Figure 22; and Figures 24 to 27 are elevation views of the locking element of Figure 22.

[0064] It should be noted that the Figures may not be drawn to scale.DETAILED DESCRIPTION

[0065] A watercraft 10 in accordance with an embodiment of the present technology is illustrated in Figs. 1 to 7. As can be seen, in this embodiment, the watercraft 10 is a surfboard with a lift-propulsion system 50 connected to and suspended therebeneath, sometimes referred to as an "eFoil", for riding by an operator. However, the watercraft 10 may be any other suitable type of watercraft in other embodiments (e.g., a wakeboard, a personal watercraft (PWC), etc.).

[0066] The watercraft 10 has a buoyant body 12 having upper and lower surfaces 14, 16 on respective upper and lower sides 18, 20 of the buoyant body 12. In use, the operator of the watercraft 10 is positioned on the upper surface 14 (e.g., standing, kneeling, sitting, lying down) to ride the watercraft 10, whereas the lower surface 16 is configured to engage the surface of the water when the watercraft 10 is underway (and the lift-propulsion system 50 is in a retracted state as will be described further below). The buoyant body 12 has a front end 22 and a rear end 24 defining a length of the buoyant body 12 therebetween. As shown in Fig. 3, a longitudinal center axis 25 of the watercraft 10 extends longitudinally between the front end 22 and the rear end 24 and bisects a width of the buoyant body 12. The axis 25 defines a longitudinal direction for the watercraft 10.

[0067] In this embodiment, the buoyant body 12 is a molded plastic buoyant body (i.e., it is molded into shape from a plastic material) with a foam core. It is contemplated that the buoyant body could be made from different materials and using a different process. For example, the buoyant body could be made from a foam core laminated with fiberglass or carbon fiber. Moreover, in the illustrated embodiments, the buoyant body 12 has a generally elliptical shape. It is to be understood that the configuration of the buoyant body 12 may be different in other embodiments.

[0068] The buoyant body 12 defines a plurality of handholds 26 at various locations to allow the operator to hold onto the watercraft 10 such as for reboarding the watercraft 10 or hold the watercraft 10 during transport. The handholds 26 may be positioned at different locations of the buoyant body 12 in different embodiments. In other embodiments, the handholds 26 may be omitted. In the present embodiment, the buoyant body 12 has a length of about 2 meters and a beam of about 1 meter.

[0069] The watercraft 10, in accordance with the present technology, includes a lift-propulsion system 50 that can selectively provide lift and propulsion to the watercraft 10. In the present embodiment, the lift-propulsion system 50 can be selectively retracted or deployed at will to accommodate a desired operating mode of the operator of the watercraft 10. It is contemplated that in some embodiments, the lift-propulsion system 50 may not be retractable.

[0070] As shown in Figure 6, the buoyant body 12 also defines a chamber 87 between the upper and lower surfaces 14, 16 of the buoyant body 12. The chamber 87 accommodates various components of the retractable lift-propulsion system 50 therein. A flexible panel 97 is connected to the buoyant body 12 on the lower side 20 thereof in order to accommodate the retractable lift-propulsion system 50 when in a retracted position; see for instance Figs. 2 and 4. The flexible panel 97 defines a slit 98 extending generally longitudinally. The flexible panel 97 may be made of any suitable flexible material. For instance, in this embodiment, the flexible panel 97 is made of rubber, an elastomer or other flexible and resilient material. For more details on embodiments of retractable lift-propulsion systems, see for instance International Application Publication WO2022 / 091035, published May 5, 2022, the entirety of which is incorporated herein by reference.

[0071] With additional reference to Fig. 8, the retractable lift-propulsion system 50 includes a mast 52 and a lift-propulsion assembly 60 connected thereto. The mast 52 connects the lift-propulsion assembly 60 to the buoyant body 12. The mast 52 has a proximal end 54 and a distal end 56 opposite one another. In this embodiment, the proximal end 54 of the mast 52 is pivotally connected to the buoyant body 12 of the watercraft 10. The mast 52 is pivotable between a retracted position (Figs. 1 to 4) and a deployed position (Figs. 5 to 7), as well as one or more intermediate positions (not shown). The number of possible intermediate positions could vary in different embodiments, in some cases with no intermediate positions.

[0072] In the retracted position, the mast 52 extends generally parallel to the longitudinal center axis 25 of the watercraft 10 and a majority of the mast 52 is disposed between the upper and lower surfaces 14, 16 of the buoyant body 12. In the deployed position, the mast 52 extends from the lower side 20 of the buoyant body 12 and the mast 52 extends through the slit 98 of the flexible panel 97. A distance between the distal end 56 of the mast 52 and the lower surface 16 of the buoyant body 12 is greater in the deployed position than in the retracted position. When the watercraft 10 is underway and the mast 52 is in the retracted position, the lift-propulsion assembly 60 does not provide any significant lift to the watercraft 10 but can still provide thrust to the watercraft 10. When the watercraft 10 is underway and the mast 52 is in an intermediate or deployed position, the lift-propulsion assembly 60 provides lift to the watercraft 10 and can also provide thrust to the watercraft 10.

[0073] With additional reference to Figs. 9 to 17, the lift-propulsion assembly 60, also referred to herein as the assembly 60, includes a hydrofoil 100 and a propulsion unit 64. The assembly 60 also includes an assembly frame 80, also referred to herein as the frame 80, for supporting components of the assembly 60. The assembly frame 80 is connected to the distal end 56 of the mast 50 (Fig. 7). As will be described in more detail below, the hydrofoil 100 is selectively connected to the assembly frame 80, in order to permit disassembly for traveling and / or storage, as well as to permit replacement of the hydrofoil 100 with different models of hydrofoil.

[0074] The hydrofoil 100 is configured to provide lift to the watercraft 10 while the propulsion unit 64 is configured to provide thrust to the watercraft 10. The lift-propulsion assembly 60 is connected to the distal end 56 of the mast 52 such that, in the deployed position of the mast 52, the lift-propulsion assembly 60 is distanced from the buoyant body 12 and, in the retracted position of the mast 52, the lift-propulsion assembly 60 is proximate the buoyant body 12. The proximity of the lift-propulsion assembly 60 to the buoyant body 12 in the retracted position of the mast 52 is helpful to make the watercraft 10 compact and easy to transport and able to operate in shallower waters.

[0075] The propulsion unit 64 includes a rotor 70 rotatable about a rotating axis. In this embodiment the rotor 70 is an impeller 70 having blades that, when rotated about the rotating axis, transform rotational power into linear thrust by acting upon water. The impeller 70 is surrounded by a duct 74. It is contemplated that the impeller 70 could be another type of rotor in other embodiments such as a propeller.

[0076] The lift-propulsion assembly 60 has an electric motor 76 (Fig. 14) for driving the impeller 70 of the propulsion unit 64. As can be seen, in this embodiment, the electric motor 76 is connected to the frame 80. More specifically, the electric motor 76 is enclosed within the frame 80. Portions of the frame 80 are generally tubular and extend in a longitudinal direction of the watercraft 10 (i.e., generally parallel to the center axis 25). In this embodiment, the electric motor 76 is a 6kW motor, but other types of electric motors are contemplated.

[0077] An electrical assembly 82 (shown schematically in Fig. 7) is provided to work in conjunction with the electric motor 76. The electrical assembly 82 is supported by the buoyant body 12. In particular, the electrical assembly 82 is housed inside the buoyant body 12. In particular, in this embodiment, the electrical assembly 82 has a battery 84 (shown schematically) which stores energy for powering the electric motor 72 and an inverter 86 (shown schematically) in electrical communication between the battery 84 and the electric motor 72. In this embodiment, the battery 84 has a nominal voltage of approximately 48V and a capacity of approximately 2.5 kWh, but batteries having other nominal voltages and power capacities are contemplated. The inverter 86 converts the direct current (DC) of the battery 84 to alternating current (AC) which powers the electric motor 76. As shown in Fig. 8, electrical wires 93 extend within the mast 52 to electrically connect the electric motor 76 to the electrical assembly 82. It is contemplated that more than one battery 84 could be provided. In at least some embodiments, a charging plug (not shown) could be provided in the buoyant body 12 and be electrically connected to the battery 84. The charging plug could thus be electrically connected to a power source (e.g., an electrical outlet) to charge the battery 84.

[0078] According to the present technology, assembly 60 includes the selectively connected front hydrofoil 100, as well as a rear foil 92 disposed rearward of the front foil 100. When the mast 52 is in a deployed or intermediate position and the watercraft 10 is underway moving forwardly above a certain speed, the hydrofoils 100, 92 lifts the buoyant body 12 completely out of the water thereby decreasing drag and allowing the watercraft 10 to attain greater speeds. The front foil 100 has a greater lateral span than the rear foil 92.

[0079] The rear foil 92 has two wings 94, each extending laterally from a respective lateral side of the propulsion unit 64 in opposite directions. The hydrofoils 100, 92 and the propulsion unit 64 are connected to the assembly frame 80 of the lift-propulsion assembly 60. In the present embodiment, the rear foil 92 is integrally connected to the assembly frame 80. In some embodiments, it is contemplated that the rear foil 92 could be fastened to the assembly frame 80. It is contemplated that the hydrofoils 100, 92 could be configured differently in other embodiments. While providing two foils 100, 92 has certain hydrodynamic advantages, it is contemplated that the a single foil could be used in place of front and rear foils 100, 92 some embodiments.

[0080] In Figures 18 to 21, the hydrofoil 100 is illustrated in isolation, removed from the remaining components of the assembly 60. The hydrofoil 100 is formed from a continuous foil body 102. The body 102 includes two wings 103, each extending laterally from a respective lateral side of a center portion 104 in opposite directions. The exact form of the wings 103 could vary in different embodiments. The center portion 104 and the wings 103 are integrally formed in the illustrated embodiment.

[0081] The center portion 104 of the hydrofoil 100 aids in selectively connecting the hydrofoil 100 to the assembly frame 80 and in maintaining the connection therebetween during use. Specifically, the center portion 104 defines therein a female tapered portion 106. The tapered portion 106 receives therein a portion of the assembly frame 80, specifically a male tapered portion 180 (see Figs. 10, 12, and 14 to 17). The male tapered portion 180 is engaged in the female tapered portion 106 when the hydrofoil 100 is connected to the assembly frame 80. Both the tapered portions 10 extend and taper along the longitudinal direction of the watercraft 10. In the illustrated embodiment, top, bottom, and lateral side surfaces of each tapered portion 106, 180 taper along the longitudinal direction of the watercraft 10. The mating tapered portions 106, 180 permit the hydrofoil 100 to be easily translated onto and off of the assembly frame 80 (when not otherwise secured in place, described below), while providing some stability during use. As the female tapered portion 106 opens rearward from a rear side of the hydrofoil 100, forces during use on the hydrofoil 100 reinforce the connection to the assembly frame 80 via the mated tapered portions 106, 180. It is contemplated that in some embodiments, the hydrofoil 100 could include a male tapered portion and the assembly frame 80 could include a mating female tapered portion.

[0082] Returning to Figs. 9 to 17, the assembly 60 further includes a manually-operable attachment system 130 for selecting connecting the hydrofoil 100 to the assembly frame 80. More specifically, the attachment system 130 selectively secures the hydrofoil 100 to the assembly frame 80 when the tapered portions 106, 180 are connected in order to maintain the hydrofoil 100 in place. As will be described in more detail below, the attachment system 130 is manually-operable such that an operator can selectively connect and disconnect the hydrofoil 100 without the use of tools.

[0083] Broadly, the attachment system 130 includes a rigid connection member 190 connected to the assembly frame 80 and a locking element 150 pivotally connected to the hydrofoil 100. The hydrofoil 100 is selectively maintained connected to the assembly frame 80 in part by engagement of the locking element 150 with the rigid connection member 190. The locking element 150 and the rigid connection member 190 will be described in greater detail below. To selectively connect and disconnect the hydrofoil 100 with the assembly frame 80, the locking element 150 is selectively rotatable between an unlocked position and a locked position. Operation of the locking element 150 is described in more detail below.

[0084] With reference to Figs. 10, 12, and 14 to 17, the rigid connection member 190 includes a stem 192 and a distal end portion 194 connected to the stem 192. The distal end portion 194 has a greater width than the stem 192. In the present embodiment, the distal end portion 194 is generally cylindrical with a greater diameter than the stem 192. Specifically, the member 190 is in the form of a bolt head. In different embodiments, different forms of rigid members with larger distal end portions or with a T-shaped cross-section could be used. The rigid connection member 190 is connected to the front end of the male tapered portion 180 on the assembly frame 80, as will be described further below.

[0085] The locking element 150 is shown in more detail in Figs. 22 to 27. The locking element 150 includes an element body 152 defining a slot 154 therein. A handle portion 159 is integrally connected to the element body 152 to permit the operator to turn the locking element 150 between the unlocked and locked positions.

[0086] The slot 154 is shaped and arranged to selectively permit the rigid connection member 190 to pass therethrough (in the unlocked position) and to selectively maintain the rigid connection member 190 in the locking element 150 (in the locked position). Specifically, a first portion 155 of the slot 154 is wider than a width of the distal end portion 194, permitting the distal end portion 194 to pass through the first portion 155. A second portion 157 of the slot 154, radially opposite the first portion 155, is wider than a diameter of the stem 192 and narrower than the width of the distal end portion 194, preventing the distal end portion 194 from passing through the second portion 157. The first (wider) portion 155 of the slot 154 is arranged at one end of the slot 154, with the second (narrower) portion 157 of the slot 154 arranged at the opposite end. In the present embodiment, the slot 154 extends over about half of the circumference of the element body 152, such that the portions 155, 157 are separated by about 180 degrees about the center of the locking element 150. Connection and disconnection are described further below.

[0087] The locking element 150 is formed from hard plastic, but other materials, including but not limited to hard rubber, are contemplated. In the illustrated embodiment, the locking element 150 is one integrally-formed piece, but it is contemplated that the element 150 could be formed from multiple separately-formed pieces connected together.

[0088] The locking element 150 is pivotally connected to the hydrofoil 100. Specifically, the hydrofoil body 102 defines therein a cavity 110 for receiving the locking element 150 (see Figs. 12, 19). The locking element 150 further includes a resilient portion 153 for clipping into a socket 109 (Fig. 21) formed into the hydrofoil body 102 for maintaining the locking element 150 in the cavity 110. It is contemplated that the locking element 150 could be differently connected to the hydrofoil 100. When installed in the hydrofoil 100, the locking element 150 is rotatable or pivotable about an axis 151, perpendicular to a bottom surface of the hydrofoil 100, between a locked position and an unlocked position. In the illustrated embodiment, the handle portion 159 is accessible on a lower side of the hydrofoil 100. In different embodiments, it is contemplated that the locking element 150 could be differently oriented and arranged.

[0089] The cavity 110 of the hydrofoil 100 is open into the female tapered portion 106, such that, when mounting the hydrofoil 100 on the assembly frame 80, the rigid connection member 190 passes through the female tapered portion 106 into the cavity 110. Specifically, with the locking element 150 in the unlocked position, the first portion 155 of the slot 154 is aligned with the rigid connecting member 190, such that the rigid connecting member 190 can be inserted through the slot 154 for selectively securing the hydrofoil 100 to the assembly frame 80 when the male tapered portion 180 is inserted into the female tapered portion 106. Similarly, with the locking element 150 in the unlocked position, the first portion 155 of the slot 154 is aligned with the rigid connecting member 190, such that the rigid connecting member 190 can be removed through the slot 154 for selectively disconnecting the hydrofoil 100 from the assembly frame 80, the male tapered portion 180 then being removed from the female tapered portion 106.

[0090] In the locked position, and with the hydrofoil 100 connected to the assembly frame 80, the second portion 157 of the slot 154 is aligned with the rigid connecting member 190, preventing the rigid connecting member 190 from being removed from the locking element 150. The hydrofoil 100 is thus prevented from being removed from the assembly frame 80 by the rigid connecting member 190 being engaged with the locking element 150. In the present embodiment, the locking element 150 is rotated by the operator by a half turn (180 degrees) to move between the unlocked and locked positions. It is contemplated that the locking element 150 could be configured and arranged to have a greater or lesser rotation for moving between the unlocked and locked positions.

[0091] While the present technology has been discussed with respect to one hydrofoil 100 being connected to and disconnected from the assembly frame 80, it is contemplated that the selectively removable hydrofoil 100 could be a set of exchangeable hydrofoils, each hydrofoil of the set having the female tapered portion 108 and the locking element 150 configured to connect to the assembly frame 80 and the connecting member 190. The present technology thus provides for a system for adapting the hydrofoil to a desired use of the watercraft 10, while maintaining an ease of use through the manually-operable attachment system 130.

[0092] Modifications and improvements to the above-described embodiments of the present technology may become apparent to those skilled in the art. The foregoing description is intended to be exemplary rather than limiting. The scope of the present technology is therefore intended to be limited solely by the scope of the appended claims.

Claims

1. A watercraft, comprising: a buoyant body having upper and lower surfaces on respective upper and lower sides thereof; a lift-propulsion system comprising: a mast connected to the buoyant body, the mast having a proximal end and a distal end, the mast extending from the lower side of the buoyant body; and a lift-propulsion assembly comprising: an assembly frame connected to the distal end of the mast; a propulsion unit for providing thrust to the watercraft, the propulsion unit being connected to the assembly frame; a hydrofoil for providing lift to the watercraft, the hydrofoil being selectively connected to the assembly frame; and a manually-operable attachment system connecting the hydrofoil to the assembly frame.

2. The watercraft of claim 1, wherein: the assembly frame comprises one of a male tapered portion and a female tapered portion; the hydrofoil comprises an other one of the male tapered portion and the female tapered portion; and the male tapered portion is engaged in the female tapered portion when the hydrofoil is connected to the assembly frame.

3. The watercraft of claim 2, wherein the male tapered portion and the female tapered portion extend and taper along a longitudinal direction of the watercraft.

4. The watercraft of any one of claims 1 to 3, wherein: the attachment system comprises a rigid connection member connected to a one of the assembly frame and the hydrofoil; and the hydrofoil is selectively maintained connected to the assembly frame at least in part by engagement of the rigid connection member with an other one of the assembly frame and the hydrofoil.

5. The watercraft of claim 1, wherein: the attachment system comprises a locking element connected to a one of the assembly frame and the hydrofoil; the locking element is selectively rotatable between a locked position and an unlocked position; and the hydrofoil is selectively maintained connected to the assembly frame at least in part by engagement of the locking element with an other one of the assembly frame and the hydrofoil.

6. The watercraft of claim 5, wherein: the locking element is pivotally connected to the hydrofoil; and the hydrofoil is selectively maintained connected to the assembly frame by engagement of the locking element with the assembly frame.

7. The watercraft of claim 1, wherein: the attachment system comprises: a rigid connection member connected to the assembly frame, and a locking element pivotally connected to the hydrofoil; and the hydrofoil is selectively maintained connected to the assembly frame at least in part by engagement of the locking element with rigid connection member.

8. The watercraft of claim 7, wherein: the locking element comprises: an element body defining a slot therein, and a handle portion connected to the element body; and the rigid connection member comprises: a stem, and a distal end portion connected to the stem, the distal end portion having a greater width than the stem.

9. The watercraft of claim 8, wherein: at least a first portion of the slot is wider than a width of the distal end portion, permitting the distal end portion to pass through the first portion; and at least a second portion of the slot, opposite the first portion, is wider than a diameter of the stem and narrower than the width of the distal end portion, preventing the distal end portion from passing through the second portion.

10. The watercraft of claim 9, wherein: the locking element is selectively rotatable between at least an unlocked position and a locked position; in the unlocked position, the first portion of the slot is aligned with the rigid connecting member, such that the hydrofoil is selectively removable from the assembly frame; and in the locked position, with the rigid connecting member being engaged with the locking element, the second portion of the slot is aligned with the rigid connecting member, such that the hydrofoil is prevented from being removed from the assembly frame.

11. The watercraft of any one of claims 8 to 10, wherein the handle portion is accessible on a lower side of the hydrofoil.

12. The watercraft of any one of claims 1 to 11, wherein: the hydrofoil is a front hydrofoil; and the lift-propulsion assembly further comprises a rear hydrofoil connected to the assembly frame, the rear hydrofoil being disposed rearward of the front hydrofoil when the front hydrofoil is selectively connected to the assembly frame.

13. The watercraft of any one of claims 1 to 12, wherein the lift-propulsion assembly further comprises an electric motor for driving the propulsion unit.

14. The watercraft of any one of claims 1 to 13, wherein the lift-propulsion system further comprises an electrical assembly supported by the buoyant body, the electrical assembly comprising: a battery for powering the electric motor; and an inverter in electrical communication between the battery and the electric motor.

15. The watercraft of any one of claims 1 to 14, wherein the propulsion unit comprises one of a propeller and an impeller.

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