A variety of self-propelled personal watercraft are available for aquatic recreation. These include surfboards, paddleboard, kayaks, standup paddle boards, and the like. However, all of these products support the weight of the user with a single buoyant device and require another source of propulsion such as a wave in surfboard or a paddle with paddle board, kayak, or standup paddle boards. An aquatic recreation device which enables bipedal aquatic locomotion provides new aquatic recreation opportunities and is an advancement in the field.
An exemplary embodiment of a personal bipedal watercraft includes a pair of skis. Each ski of the pair skis includes a floating hull. A deck is secured to the hull. A binding on the deck is configured to receive a foot of a user. A plurality of paddle assemblies are secured to the floating hull. Each paddle assembly of the plurality of paddle assemblies includes a blade and a fin.
In an additional exemplary embodiment, the paddle assemblies are pivotably secured to the hull and the paddle assemblies are movable between a closed position wherein the blade is positioned against the hull and an open position wherein the blade is positioned away from the hull. In a further exemplary embodiment, the fins of the paddle assemblies are perpendicular to the blades of the paddle assemblies. In a further exemplary embodiment, a cord is elastically secured between each ski of the pair of skis.
An exemplary embodiment of a method of bipedal water travel includes providing a pair of skis. Each ski of the pair includes a floating hull, a deck secured to the hull, and a binding on the deck. The binding is configured to receive a foot of a user. Each ski includes a plurality of paddle assemblies which are pivotably secured to the floating hull. Each paddle assembly of the plurality includes a blade and a fin secured perpendicularly to the blade. A backward force is applied to a first ski of the pair of skis. The backward force moves the plurality of paddle assemblies of the first ski from a closed position to an open position to increase a water resistance of the first ski. A forward force is applied to the second ski of the pair of skis. The forward force moves the plurality of paddle assemblies of the second ski from an open position to a closed position to decrease a water resistance of the second ski. The forward force moves at least a portion of the second ski forward past a portion of the first ski.
Each ski 12 includes a deck 20, the deck 20 is generally flat and supports the user in a standing position on the water with the user's feet at a position on the deck 20 above the water line. The length, beam, and draft of each ski contributes to supporting the user's feet at a position above the water line. A traction area 22 may be formed on the deck 20. The traction area 22 may be constructed of a rubber or other polymeric material to facilitate traction of a user on the deck 20 of the ski 12, particularly when the surface of the traction area 22 is wet. In an embodiment, the traction area 22 may include a surface treatment of the deck 20 including, but not limited to ridges, dimples, or the like formed in deck 20 of the ski 12.
Each ski 12 exemplarily includes a binding 14 on the deck 20. In an exemplary embodiment, the binding 14 extends upwards from the deck 20. The binding 14 operates to provide a manner by which the user's foot is movably secured to the ski 12. In an exemplary embodiment, the binding 14 includes a pivoting clip 16 that pivotably secures a shoe 18 worn by the user to the ski 12 in a pivotable manner. In an exemplary embodiment a cleat is positioned on the bottom of each show that engages with and secures to a locking mechanism on the pivoting clip 16. In another embodiment, the cleat is positioned on the pivoting clip 16 and the locking mechanism positioned in the bottom of the shoe 18. The engagement of the shoe with the pivoting clip 16 in this manner provides efficient power transfer between the user's legs and feet and the skis 12 of the personal bipedal watercraft 10. The pivoting motion of the clip 16 provides comfort to the user by facilitating a more natural “heel off” striding motion as is exemplarily depicted in
An underside 24 of the ski 12 is provided by the hull 13 and located opposite the deck 20. The underside 24 is generally flat and smooth such as to reduce drag when moving through the water and to reduce the draft of skis 12 when in use. A plurality of paddle assemblies 26 are movably connected to the underside 24. While the embodiment depicted in
A flexible cord 30 is secured between back ends 32 of the skis 12. In the embodiment depicted, the flexible cord 30 comprises a hook 36 at either end. The hooks 36 are respectively secured to eyelets 34 located at the back ends 32 of the skis. In an exemplary embodiment, the hooks 36 may be carabineers with a spring biased gate to bias the carabineer gate in a closed position. In another embodiment, the hooks 36 may have a threaded-lock gate that removably secures the gates in a closed position about the respective eyelets 34.
The paddle assemblies 26, which will now be described in further detail are exemplarily best depicted in
The blade 40, as well as the rest of the paddle assembly 26, pivots about the hinge 42. The hinge 42 may be provided exemplarily with a hinge pin or in another embodiment may be a living hinge of a flexible material. The blade 40 pivots between a closed position, wherein the blade 40 is against the underside 24 of the ski 12, and an open position wherein the blade 40 is generally perpendicular to the underside 24. In the closed position, the blade 40 may be flush or parallel to the underside 24. Positioning of the blade 40 in this manner, when in the closed position, may reduce drag during operation.
The blade 40 includes a bow side 41 and a stern side 43. As described above, the stern side 43 pivots into and out of proximity with the underside 24 of the ski 12. The fin 38 extends perpendicularly away from the bow side 41 of the blade 40 in the direction towards the front of the ski 12 when the blade 40 is in the open position. In some exemplary embodiments, flanges 44 extend from the fin 38 to help secure the fin 38 to the blade 40. As the paddle assembly 26 and the blade 40 pivot about the hinge 42, so too does the fin 38. When the paddle assembly 26 and the fin 38 are in the open position, the fin 38 is pointed in the direction of the bow of the ski 12. When the paddle assembly 26 and the fin 38 are in the closed position, the fin 38 is pointed below the ski 12 extending away from the underside 24 of the ski.
The paddle assembly 26 exemplarily pivots about the hinge 42 through an angle of about 90 degrees. This is exemplarily depicted in
The paddle assembly 26 is able to rotate about the hinge 42 in the direction indicated by arrows in
In use, the user, wearing the shoes 18 secured to the bindings 14 stands upright on both of the skis 12. The user alternatingly applies a force, exemplarily a forward force, to each of the skis in a bipedal manner. The hinges 42 enable the paddle assemblies 26 to move partially independently to the user's movements that the skis 12 to which the user's feet are secured. One problem with aquatic propulsion is that due to the law of conservation of mass, forward propulsion requires a similar mass projected backwards. Currently available personal watercraft provide a flat or rounded bottoms which reduce water resistance against forward movement but do nothing to drive the backward movement of water to achieve the forward movement. Typically this must be provided by a paddle (as in canoeing, kayaking, or stand-up paddleboard) or another structure operated by the user e.g. in the cowl of a row boat or a paddle boat. The partially independent movement of the paddle assemblies 26 relative to the skis enable bipedal aquatic locomotion by providing the transfer the backward force against the water.
During bipedal locomotion, one foot/ski provides the backward force against the water while the other foot/ski is moved forward. The paddle assemblies 26 of one ski respond to the backward force and move into the open position. In an embodiment, the curved tip 48 of the blade 40 may provide surface area to catch water when the paddle assembly 26 is moved backwards, moving the blade 40 from the closed position to the open position. The curved tip 48 is exemplarily curved in the direction towards the fin. This may create a space between the free edge of the blade 40 at the curved tip 48 and the underside 24 of the ski 12. This space provides a surface area to catch the water as the ski 12 moves backwards which may help to overcome any surface tension between the stern side 43 of the blade 40 and the underside 24 of the ski 12. The paddle assembly 26 moves about the hinge 42 until the paddle assembly 26 reaches the open position. When the fin 38 engages the underside 24 of the ski 12, and the paddle assembly 26 is fully in the open position, the blade 40 transfers force from ski 12 to the water. In one embodiment, when the paddle assembly 26 is in the open position, the fin 38, while curved away from the underside 24 of the ski 12, does not extend below a free edge of the blade 40, which may include the curved tip 48. In another embodiment, when the paddle assembly 26 is in the open position, the fin 38 curves away from the underside 24 of the ski 12 a sufficient amount that a portion of the fin 38 extends below the free edge of the blade 40 and/or the curved tip 48. In such an embodiment, the fin 38 may help to further stabilize the ski 12 while the paddle assemblies 26 are in the open positions.
While one ski 12 is responding to the backward force of the bipedal locomotion, the other ski 12 of the pair is receiving a forward force from the user. The forward force from the user on the other ski 12 begins to move the ski 12 forward the water resistance of the water against the bow face 41 of the blade 40 causes the paddle assembly 26 to move about the hinge 42 from the open position to the closed position. In an embodiment wherein the blade 40 includes a curved tip 48, as described above, the bow side 41 of the curved tip 48 creates a cup when the paddle assembly 26 is in the open position that helps to catch the water, which results in more force against the bow side 41 of the blade 40 to move the paddle assembly 26 into the closed position. In the closed position 26, the paddle assembly 26 minimizes water resistance as the ski 12 is moved forward through the water. Additionally, when the paddle assembly 26 is in the closed position, the fin 38 is rotated into a downward position. The fin 38 extends downward from the underside 24 of the ski 12. In this position, the fin 38 helps to keep the ski 12 stable and moving in a straight line. This can further improve the efficiency of the transfer of force from the user into forward motion of the ski 12.
The inventor has found that during operation, the skis 12 tend to move outward from one another. The fins 38 help to keep the skis together and moving in generally parallel lines to one another through the water. The stabilizing fin 28 provides a similar function and advantage. While some embodiments may operate without the stabilizing fin 28, the stabilizing fin can operate to provide stability to the ski 12 and to maintain straight motion of the skis 12, by providing a constant stabilizing presence while the fins 38 of paddle assemblies 26 intermittently provide this support when a respective ski 12 is moving forward.
As described above, a flexible cord 30 is secured between the skis 12, exemplarily at the back ends 32 of the skis 12. The inventor has found that the flexible cord as arranged in this manner serves two purposes which improve the operation of the personal bipedal watercraft. First, the flexible cord 30 helps to keep the skis 12 from separating and help the skis to track together during use. The flexible cord 30 does this by defining an outer extent by which the skis 12 or portions of the skis 12 may separate. Also, as the skis 12 reach that outer extent, the elasticity of the flexible cord 30 applies a restorative force against the skis 12 to bring them back together. While the flexible cord is depicted as being secured to the back ends 32 of the skis 12, it will be recognized that the flexible cord may be secured at other positions along the skis 12. Additionally, two or more flexible cords may be secured between the skis 12.
Secondly, energy is stored in the flexible cord 30 during each stride of the user's locomotive operation of the personal bipedal watercraft 10. The user pushes backwards with one ski 12 while moving the other ski 12 forward through the water. This separates the two back ends 32 of the skis 12, stretching the flexible cord 30. Stretching of the flexible cord stores energy in the stretched flexible cord 30. As the user transitions to the next step of the stride, the energy stored in the flexible cord 30 forces the rear ski forward which helps to overcome inertia of that ski 12 as the user begins to move that ski 12 forward. This promotes efficiency in the operation of the personal bipedal watercraft 10 and enhances overall usability.
In operation, the restorative force is applied as the rearmost ski 12 of the pair of skis is started to move forward. The restorative force assists the initial motion of the ski 12 forward, for example, while the paddle assemblies 26 are in the open position or being moved from the open position to the closed position and the ski 12 has increased water resistance from the open or partially open paddle assemblies. Once the moving ski 12 begins to move in front of the other ski, then the flexible cord 30 switches from retracting to again stretching, storing energy during the rest of the movement of that ski. The stored energy is held in the flexible cord 30 to be released when the user switches feet to begin moving the other ski 12 forward in the same manner.
In the above description, certain terms have been used for brevity, clarity, and understanding. No unnecessary limitations are to be inferred therefrom beyond the requirement of the prior art because such terms are used for descriptive purposes and are intended to be broadly construed. The different systems and method steps described herein may be used alone or in combination with other systems and methods. It is to be expected that various equivalents, alternatives and modifications are possible within the scope of the appended claims.
This written description uses examples to disclose the invention, including the best mode, and also to enable any person skilled in the art to make and use the invention. The patentable scope of the invention is defined by the claims, and may include other examples that occur to those skilled in the art. Such other examples are intended to be within the scope of the claims if they have structural elements that do not differ from the literal language of the claims, or if they include equivalent structural elements with insubstantial differences from the literal languages of the claims.
The present application claims priority of U.S. Provisional Patent Application No. 62/289,618, filed on Feb. 1, 2016, the content of which is hereby incorporated herein by reference in its entirety.
Number | Date | Country | |
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62289618 | Feb 2016 | US |