PRIORITY APPLICATION

[0001] This application claims priority to U.S. Provisional Patent Application No. 63/197,904, filed June 7, 2021, which is incorporated herein by reference in its entirety and for all purposes.

BACKGROUND

Field

[0002] This application relates to personal watercraft, such as, kayaks, canoes, and the like. More particularly, this application relates to personal watercraft that include a fishtail propulsion system.

Description

[0003] Personal watercrafts, such as, kayaks, canoes, paddleboards, etc., are typically maneuvered by a user using a handheld paddle. In these instances, a user uses the handheld paddle to propel and steer the watercraft. Using a handheld paddle to maneuver a watercraft can tire a user, making maneuvering a watercraft difficult over an extended period of time. In some instances, personal watercrafts can include a motorized propeller, which can increase maneuverability.

SUMMARY

[0004] Described herein are personal watercrafts that include fishtail propulsion systems.

[0005] In a first aspect, a watercraft can include: a hull configured to float in water and including a cockpit configured to carry at least one passenger; a fishtail propulsion system comprising a pivot body pivotally coupled to a stern of the hull, the pivot body configured to pivot about an axis, the pivot body further comprising a recess configured to receive a pump system, a flexible paddle coupled to the pivot body such that the paddle pivots about the axis with the pivot body, and a pedal system comprising pedals operably coupled to the pivot body, wherein the pedals are configured to be actuated to cause the pivot body and the paddle to pivot about the axis, thereby causing the paddle to move in a side-to-side manner; and a pump system received in the recess of the pivot body, the pump system comprising a water intake and a water exhaust, the pump system configured to intake water through the water intake and exhaust water through the water exhaust to provide a propulsive force for the watercraft.

[0006] The watercraft can include one or more of the following features in any combination: (a) wherein the pedals are positioned within the cockpit and configured to be foot-operable; (b) the pedals comprise a right pedal and a left pedal, and the pedal system is configured such that alternatingly depressing the pedals causes the paddle to move back and forth in the side-to-side manner; (c) wherein the right pedal is operably connected to a right portion of the pivot body by a first linking mechanism, and the left pedal is operably connected to a left portion of the pivot body by a second linking mechanism; (d) wherein the first linking mechanism comprises a first cable, and the second linking mechanism comprises a second cable; (e) wherein the paddle comprises a flexibility that varies along a length of the paddle; (f) wherein the flexibility of the paddle increases from a proximal end of the paddle to a distal end of the paddle; (g) wherein the axis about which the pivot body pivots comprises a vertical axis; (h) wherein the paddle is configured to move in the side-to-side manner with a range of motion of at least 30 degrees; (i)wherein the paddle is configured to move in the side-to-side manner with a range of motion of at least 45 degrees; (j) wherein the paddle is configured to move in the side-to-side manner with a range of motion of at least 60 degrees; (k) wherein the pump system is removably received within the recess of the pivot body; (1) wherein the hull further comprises a recess formed on an underside of the hull, and further comprising a second pump system received in the recess of the hull; (m) wherein the second pump system is removably received in the recess of the hull; (n) wherein the paddle does not extend lower than a lowest surface of the hull; (o) wherein the paddle extends at most 20 cm lower than a lowest surface of the hull; (p) the watercraft comprises a kayak; and/or other features as described throughout this disclosure.

[0007] In another aspect, a watercraft can include: a hull configured to float in water and including a cockpit configured to carry at least one passenger; and a fishtail propulsion system comprising a pivot body pivotally coupled to a stem of the hull, the pivot body configured to pivot about an axis, the pivot body further comprising a recess configured to receive a pump system, a flexible paddle coupled to the pivot body such that the paddle pivots about the axis with the pivot body, and a pedal system comprising pedals operably coupled to the pivot body, wherein the pedals are configured to be actuated to cause the pivot body and the paddle to pivot about the axis, thereby causing the paddle to move in a side-to- side manner.

[0008 ] The watercraft can include one or more of the following features in any combination: (a) wherein the pedals are positioned within the cockpit and configured to be foot-operable; (b) wherein the pedals comprise a right pedal and a left pedal, and the pedal system is configured such that altematingly depressing the pedals causes the paddle to move back and forth in the side-to-side manner; (c) wherein the right pedal is operably connected to a right portion of the pivot body by a first linking mechanism, and the left pedal is operably connected to a left portion of the pivot body by a second linking mechanism; (d) wherein the first linking mechanism comprises a first cable, and the second linking mechanism comprises a second cable; (e) wherein the paddle comprises a flexibility that varies along a length of the paddle; (f) wherein the flexibility of the paddle increases from a proximal end of the paddle to a distal end of the paddle; (g) wherein the axis about which the pivot body pivots comprises a vertical axis; (h) wherein the paddle is configured to move in the side-to-side manner with a range of motion of at least 30 degrees; (i) wherein the paddle is configured to move in the side- to-side manner with a range of motion of at least 45 degrees; (j) wherein the paddle is configured to move in the side-to-side manner with a range of motion of at least 60 degrees; (k) wherein the hull further comprises a recess formed on an underside of the hull, and further comprising a pump system received in the recess of the hull; (1) wherein the pump system is removably received in the recess of the hull; (m) wherein the paddle does not extend lower than a lowest surface of the hull; (n) wherein the paddle extends at most 20 cm lower than a lowest surface of the hull; (o) wherein the watercraft comprises a kayak; and/or other features as described throughout this disclosure.

[0009] For purposes of this summary, certain aspects, advantages, and novel features are described herein. It is to be understood that not necessarily all such advantages may be achieved in accordance with any particular embodiment. Thus, for example, those skilled in the art will recognize the disclosures herein may be embodied or carried out in a manner that achieves one or more advantages taught herein without necessarily achieving other advantages as may be taught or suggested herein. [0010] All of the embodiments described herein are intended to be within the scope of the present disclosure. These and other embodiments will be readily apparent to those skilled in the art from the following detailed description, having reference to the attached figures. The invention is not intended to be limited to any particular disclosed embodiment or embodiments.

BRIEF DESCRIPTION OF THE DRAWINGS

[0011] These and other features, aspects, and advantages of the personal watercrafts that include fishtail propulsion systems described herein will be described below with reference to drawings of certain embodiments, which are intended to illustrate, but not to limit, the present disclosure. It is to be understood that the accompanying drawings, which are incorporated in and constitute a part of this specification, are for the purpose of illustrating concepts disclosed herein and may not be to scale.

[0012] FIG. 1 A is a top perspective view of an embodiment of a personal watercraft including an embodiment of a fishtail propulsion system including an integrated pump system.

[0013] FIG. IB is a detailed bottom perspective view of the fishtail propulsion system and integrated pump system of the personal watercraft of FIG. 1A.

[0014] FIG. 1C is a top view of the personal watercraft of FIG. 1 A.

[0015] FIG. ID is a side view of the personal watercraft of FIG. 1 A.

[0016] FIG. IE is a bottom view of the personal watercraft of FIG. 1 A.

[0017] FIG. 2 A is a top perspective view' of an embodiment of a fishtail propulsion system including an integrated pump system that is configured for use with a personal watercraft.

[0018] FIG. 2B is a bottom perspective view of the fishtail propulsion system and integrated pump system of FIG. 2 A.

[0019] FIG. 3 A is a top perspective view of an embodiment of a fishtail propulsion system that is configured for use with a personal watercraft.

[0020] FIG. 3B is a bottom perspective view of the fishtail propulsion system of

FIG. 3A.

[0021] FIG. 4A is a bottom perspective view of an embodiment of a personal watercraft that includes a recess formed in an underside of a hull thereof, the recess configured to receive a pump system for propelling the personal watercraft. [0022] FIG. 4B is a bottom perspective view of an underside portion of a hull of a personal watercraft that includes a recess formed in the underside of the hull thereof, shown with a pump system for propelling the personal watercraft received within the recess.

[0023] FIG. 5 A is an exploded side view of an embodiment of a pump system configured to propel a personal watercraft as well as a corresponding recess configured to receive the pump system.

[0024] FIG. 5B is a perspective view of the pump system and corresponding recess of FIG. 5 A shown prior to insertion of the pump system into the recess.

[0025] FIG. 5C is a perspective view of the pump system and corresponding recess of FIG. 5 A shown after insertion of the pump system into the recess.

[0026] FIG. 6 is a side view of an embodiment of a personal watercraft including an embodiment of a fishtail propulsion system that is operable with a tiller.

DETAILED DESCRIPTION

[0027] Described herein are personal watercrafts that include fishtail propulsion systems. Such fishtail propulsion systems can include a paddle that extends rearwardly from the stem of the watercraft and is operable in a lateral or side-to-side manner similar to the way in which a fish uses its tail or caudal fin. The paddle can be operated in a variety of ways, including by pedal-driven systems. The paddle can be used to provide propulsive and/or steering forces. In some embodiments, the fishtail propulsion systems can be used in combination with one or more pump systems that can be configured to provide additional propulsive force.

[0028] The fishtail propulsion systems can provide one or more unique advantages. For example, in some embodiments, the fishtail propulsion systems are configured with a shape that improves the hydrodynamics of the watercraft and facilitates shallow draft operation. The fishtail propulsions systems can provide efficient propulsive force. When used in combination with a pump system, the battery power required to run the propulsive pimps can be greatly reduced. The fishtail paddle can provide improved steering and handling.

[0029] In some embodiments, the fishtail propulsion systems can be used on boats that include a squared-off stem as an add-on outboard motor on the transom, providing a more hydrodynamic shape to the watercraft, thereby improving its performance. The systems can be used on other types of boats and watercraft as well.

[0030] These and other features of the personal watercrafts that include a fishtail propulsion systems described herein will become more fully apparent from the following description of specific embodiments illustrated in the figures. These embodiments are intended to illustrate the principles of this disclosure, and this disclosure should not be limited to merely the illustrated examples. The features of illustrated embodiments can be modified, combined, removed, and/or substituted as will be apparent to those of ordinary skill in the art upon consideration of the principles of this disclosure.

[0031] FIGs. 1A-1E provide various views of an embodiment of a personal watercraft 100 including an embodiment of a fishtail propulsion system 200 including an integrated pump system 300. In particular, FIG. 1A is a top perspective view, FIG. IB is a detailed bottom perspective view' of the fishtail propulsion system and integrated pump system, FIG. 1C is a top view, FIG. ID is a side view, and FIG. IE is a bottom view.

[0032] In the illustrated embodiment, the personal watercraft 100 comprises a kayak. Although the illustrated example is shown as a kayak, the principals of this disclosure — including those related to the fishtail propulsion systems (either with or without integrated pump systems) described herein — can be applied to or modified for use with other types of personal watercrafts. For example, the principals described herein can be configured for use many types of personal watercrafts including kayaks, canoes, surfboards, inflatable watercrafts, dinghies, life rafts, tenders, sail boards, stand up paddle boards (“SUP boards"), and pool toys, among others. Further, although the watercrafts described herein are referred to as “personal," in some embodiments, such watercrafts can be configured for use by or with a capacity capable of carrying more than one person. For example, the watercrafts described herein can be used by or configured with a capacity capable of carrying one, two, three, four, or more people.

[0033] As shown in FIG. 1 A, the personal watercraft 100 comprises a hull 102. The hull 102 is configured to in size and shape to float in water and carry one or more passengers. The hull 102 in the illustrated example is configured to carry a single passenger. In general, the hull 102 extends from bow 104 to stern 106 and includes a port sidewall 108 and a starboard sidewall 110. A recess formed into an upper portion of the hull 102 forms a cockpit 112 configured to receive a user during use. In the illustrated embodiment, the cockpit includes an integrally formed seat 114 as well as several different integrally formed foot supports configured to accommodate users of different sizes. Further, in the illustrated embodiment, the hull 102 is configured as a plastic molded hull. The specific illustrated configuration of the hull 102, however, should not be considered as limiting. Many other possibilities for the size, shape, and method of manufacture of the hull exist. For example, in some embodiments, the hull may be inflatable.

[0034] With continued reference to FIG. 1A as well as with reference to the detailed view of FIG. IB, the personal watercraft 100 includes the fishtail propulsion system 200 at the stem 206 of the hull 102. In the illustrated embodiment, the fishtail propulsion system 200 includes an integrated pump system 300, although the pump system 300 need not be included in all embodiments. For example, FIGs. 3A and 3B illustrate an example fishtail propulsion system 200b that does not include an integrated pump system 300 and which will be described in more detail further below.

[0035] Returning to FIGs. 1A and IB, in the illustrated example, the fishtail propulsion system 200 includes a paddle 202 that is configured to articulate back and forth in a lateral or side-to-side manner. The lateral or side-to-side movement of the paddle 202 can be considered, in some respects, similar to the natural swimming motion provided by the tail fin or caudal fin of a fish. For this reason, the system is referred to herein as a “fishtail” propulsion system. In some embodiments, articulation of the paddle 202 can be used to propel the personal watercraft 100 and/or to steer the personal watercraft 100.

[0036] The paddle 202 is pivotally connected to the hull 102. In the illustrated embodiment, the paddle 202 is pivotally connected to the stern 106 of the hull 102. For example, a transom 118 of the stem 106 may include a post, axle, pivot, hinge, or other mechanism that is configured to pivotally connect to the paddle 202 to allow the paddle 202 to pivot in a lateral or side-to-side manner relative thereto. In the illustrated example, the paddle 202 is connected so as to pivot about an axis 208, which, in general, extends orthogonally to a plane in which the hull 102 lies. For example, the axis 208 can extend vertically or perpendicularly to the surface of water in which the personal watercraft is floating.

[0037] As shown in FIG. 1A, the fishtail propulsion system 200 can include the paddle 202 and a pedal system 204. The pedal system can include pedals 206 (e.g., right and left pedals) that are configured to be foot-operable. The pedals 206 can be positioned within the cockpit 102 of the hull in proximity to the foot supports 116. In some embodiments, the position of the pedals 206 can be adjusted to accommodate users of different sizes. For example, in some embodiments, the pedals 206 can be positioned at any of the different foot support 116 positions. In some embodiments, the pedals 206 can be positioned so as to be operated by hand.

[0038] In the illustrated embodiment, each pedal 206 is operably connected to the paddle 202. This operable connection allows the pedals 206 to be used to control the position of the paddle 202. For example, depressing the left pedal 206 can cause the distal tip of the paddle 202 to move in to the left (to the port side), and depressing the right pedal 206 can cause the distal tip of the paddle 202 to move to the right (to the starboard) side. In this way, the pedals 206 can be used to steer the personal watercraft. For example, the paddle 202 can be used as a rudder by depressing the left pedal 206 to cause the personal watercraft 100 to turn to the left and by depressing the right pedal 206 to cause the personal watercraft 100 to turn to the right.

[0039] Additionally or alternatively, the operable connection between the pedals 206 and the paddle 202 can be used to allow the paddle 202 to propel or drive the personal watercraft 100 in a forward direction. For example, by altematingly depressing the left and right pedals (e.g., left, right, left, right, left, right) the paddle 202 will be driven in a corresponding side-to-side motion that will cause the personal watercraft 100 to move in a forward direction similar to the manner in which a fish swims.

[0040] In FIGs. 1A-1E the paddle 202 is illustrated with a curved shape. In some embodiments, the paddle 202 may comprise a curved shape; however, in preferred embodiments, the paddle 202 comprises a generally flat or planar (non-curved shape). The paddle 202 may comprise a flexible material such that, during use of the paddle 202, the paddle 202 flexes or curves as it is pivoted through the water. This may, once again, facilitate a fishlike motion for the paddle 202. For example, as a fish tail swishes to the right the flexible tail bends left, storing energy that is released when the tail begins to swish left. The paddle 202 can, in some embodiments, operate in a similar manner. Thus, while the paddle 202 of FIGs. 1 A-1E is illustrated as curved, it is actually shown in a flexed state, as it may appear during use. [0041] In the illustrated embodiment of FIGs. 1 A- IE, the pedals 206 are operably connected to the paddle 202 by cables 210. Specifically, in this example, a first cable 210 extends between the left pedal 206 and the paddle 202. The first cable 210 is connected to the paddle 202 at a position on the left side of the axis 208 about which the paddle 202 pivots. The length of the cable 210 is configured such that depressing the left pedal 206 causes the cable to pull on the paddle 206 in a direction which causes a clockwise rotation of the paddle 202 about the axis 208. Similarly, a second cable 210 extends between the right pedal 206 and the paddle 202. The second cable 210 is connected to the paddle 202 at a position on the right side of the axis 208 about which the paddle 202 pivots. The length of the second cable 210 is configured such that depressing the right pedal 206 causes the cable to pull on the paddle 206 in a direction which causes a counter-clockwise rotation of the paddle 202 about the axis 208. Further, this configuration only permits one of the pedals 206 to be depressed at one time. Depressing the left pedal 206 causes the right pedal 206 to return to an undepressed position, and depressing the right pedal 206 causes the left pedal 206 to return to an undepressed position. This permits simple operation of the paddle 202 as both a rudder and a propulsion system. In some embodiments, the cables 210 comprise flexible Bowden cables, wherein force is transmitted through an inner cable that moves within a hollow outer cable housing.

[0042] In the illustrated embodiment, the right and left cables 210 extend along the interior port and starboard sidewalls 108, 110 of the hull 102 and the cables 210 are configured in size and shape to contour around a user seated in the cockpit. Other configurations are also possible. For example, the cables 210 can be routed through the hull 102 (e.g., within passages formed within the sidewalls 108, 110 or within another portion of the hull 102). Further, while illustrated as cables 210, other linking structures for operably connected the pedals 206 to the paddle 202 can be used. For example, in some embodiments, the illustrated cables 202 can be replaced with rods, chains, cords, bands, belts, etc.

[0043] Thus, the personal watercraft 100 can be steered and propelled by operating the pedals 206 to control the paddle 202. The illustrated embodiment of the personal watercraft 100 of FIGs. 1 A-1E also includes a pump system 300 for additional propulsive assistance. In the illustrated example, the pump system 300 is integrated into the paddle 202. The pump system 300 is configured to intake and accelerate water so as to provide an additional propulsive force for moving the personal watercraft 100. [0044] As best shown in the detailed view of FIG. 1 B, the pump system 300 can, in some embodiments, be integrated into a bottom surface of the paddle 202. In some embodiments, the integrated pump system 300 is removably integrated into the paddle 202. That is the pump system 300 may be provided in a housing that can be removably received into a corresponding recess formed in the bottom surface of the paddle 202. An example of such a pump system 300 that is configured to be removably received into a recess is shown in FIGs. 5A-5C, which are described in more detail below'. In other embodiments, the pump system 300 can be integrated into the paddle 202 in a generally non-removable or permanent manner.

[0045] As shown in FIG. IB, the illustrated pump system 300 includes a pump housing 302. The pump housing 302 houses the components of system 300 and forms a water intake 304 and a water exhaust 306. The pump system 300 draws water in through the water intake 304, accelerates it, and pushes it out through the water exhaust 306 in a manner that provides a force which propels the personal watercraft 100 in a forward direction. The pump system 300 can be electric and can be powered by batteries positioned within the pump housing 302 or elsewhere in the personal watercraft 100.

[0046] By integrating the pump system 300 into the paddle 202 of the fishtail propulsion assembly 200, the propulsive force provided by the pump system 300 can be directed or steered by using the pedals 206. That is, the pump system 300 can turn or pivot with the paddle 202 to direct the force.

[0047] In some embodiments, a throttle or other controller is provided, for example, in the cockpit or on a handheld remote control that allows the user to control the pump system 300. For example, a controller can be provided to activate, deactivate, and/or control the power of the pump system 300.

[0048] Example pump systems 300, including the internal components thereof, are described in detail below' with reference to FIGs. 5A-5C. Additional pump systems that can be used in combination with the fishtail propulsion system 200 are described in U.S. Pat. No. 10,689,077, entitled “Water Pump for Watercraft, which issued on June 23, 2020, from U.S. Application No. 16/570,967, filed September 13, 2019. Both U.S. Pat. No. 10,689,077 and U.S. Application No. 16/570,967 are incorporated herein by reference in their entireties and for all purposes. [0049] Although the embodiment of the personal watercraft 100 illustrated in FIGs. 1A-1E includes a pump system 300 integrated into the paddle 202 of the fishtail propulsion system, this need not be the case in all embodiments. For example, in some embodiments, the pump system 300 can be integrated ( either removably or permanently) into the hull 202 of the watercraft 100 (see the example of FIGs. 4A and 4B described below). In some embodiments, the pump system 300 can be omitted entirely or more than one pump system 300 can be included.

[0050] FIG. 1C illustrates a top down view of the personal watercraft 100. In this view, an angle 212 is shown. The angle 212 can represent the maximum degree to which the paddle 202 can pivot or rotate about the axis 208 relative to the central, longitudinal axis of the personal watercraft 100. In some embodiments, the angle 212 can be about 10 degrees, 15 degrees, 20 degrees, 25 degrees, 30 degrees, 35 degrees, 40 degrees, 45 degrees, 50 degrees, 55 degrees, 60 degrees or more. In some embodiments, the angle 212 can be at least 10 degrees, 15 degrees, 20 degrees, 25 degrees, 30 degrees, 35 degrees, 40 degrees, 45 degrees, 50 degrees, 55 degrees, 60 degrees or more. In some embodiments, the angle 212 can be at most 10 degrees, 15 degrees, 20 degrees, 25 degrees, 30 degrees, 35 degrees, 40 degrees, 45 degrees, 50 degrees, 55 degrees, 60 degrees.

[0051] Although the angle 212 is illustrated only for pivoting the paddle 202 to the port side 108 of the personal watercraft 100, it will be appreciated that the paddle 202 can also be pivoted, in equal amounts, to the starboard side 110. Accordingly, in some embodiments, the paddle 202 can be pivoted through a total range of motion of about 20 degrees, 30 degrees, 40 degrees, 50 degrees, 60 degrees, 70 degrees, 80 degrees, 90 degrees, 100 degrees, 110 degrees, 120 degrees or more. In some embodiments, the paddle 202 can be pivoted through a total range of motion of at least 20 degrees, 30 degrees, 40 degrees, 50 degrees, 60 degrees, 70 degrees, 80 degrees, 90 degrees, 100 degrees, 110 degrees, 120 degrees or more. In some embodiments, the paddle 202 can be pivoted through a total range of motion of at most 20 degrees, 30 degrees, 40 degrees, 50 degrees, 60 degrees, 70 degrees, 80 degrees, 90 degrees, 100 degrees, 110 degrees, 120 degrees.

[0052] In some embodiments, a greater range of pivoting motion for the paddle 202 can lead to an increased propulsive or steering force that can be provided by the paddle 202. Other factors also contribute to the propulsive or steering force provided by the paddle 202, including, for example, the shape of the paddle (including its height and length). Additionally, in some embodiments, gearing can be provided between the pedals 206 and the paddle 202 such that the force required to operate the pedals 206 and/or the range of motion of the paddle 202 associated with operation of the pedals 206 can be adjusted.

[0053] FIG. ID illustrates a side view of the personal watercraft 100. This view illustrates that, for some embodiments, the paddle 202 extends outwardly from the stern 106 of the hull 202 and that the overall draft of the personal watercraft 100 remains shallow. That is, in some embodiments, the paddle 202 need not extend below the lowest point of the hull 102. This can provide significant advantages when compared with other pedal driven kayak propulsion systems which generally include structures that project downwardly from a bottom surface of the hull 202 and greatly increase the draft of the kayak. As illustrated in FIG. ID, the personal watercraft 100 includes a shallow draft and is thus capable of being operated in shallow water.

[0054] In some embodiments, both the paddle 202 and the pump system 300 are positioned above the lowest point of the hull. In some embodiments, the paddle 202 is positioned above the lowest point of the hull. In some embodiments, the paddle 202 extends below the lowest point of the hull by at most 5 cm, 10 cm, 15 cm, 20 cm, 25 cm, or 30 cm.

[0055] As shown in the top view of FIG. 1C and the bottom view of FIG. IE, the fishtail propulsion 200 system provides the stem 106 of the personal watercraft 100 with a very hydrodynamic shape, facilitating its movement through the water and decreasing the amount of force required for that movement.

[0056] FIGs. 2A and 2B are top and bottom perspective views of an embodiment of the fishtail propulsion system 200 including an integrated pump system 300 that is configured for use with a personal watercraft, such as the personal watercraft 100 of FIGs. 1 A- 1E. As shown in FIGs. 2A and 2B, the fishtail propulsion system 200 includes a pivot body 220. The pivot body 220 can comprise a rigid structure configured to pivotally attach to the transom 118 at the stern 106 of the personal watercraft 100. On a proximal end (i.e., the end which attaches to the transom 118), the pivot body 108 can comprise a wider shape that can, in some embodiments, correspond in width to the width of the stem 106 of the personal watercraft 100 (see FIGs. 1C and IE) allowing a smooth and hydrodynamic transition between the hull 102 and the pivot body 108. [0057] Additionally, in some embodiments, the cables 206 (or other structures) which operate the fishtail propulsion system 200 can attach to the proximal end of the pivot body 220, and the width of the pivot body 220 provides a lever arm for the force imparted on the pivot body which causes rotation about the axis 208. In some embodiments, this lever arm (measured between the axis 208 and the point on the pivot body 220 at which the cables 206 attach) can be at about 2.5 cm, 5 cm, 7.5 cm, 10 cm, 12.5 cm, 15 cm, 17.5 cm, 20 cm, or greater. In some embodiments, the lever arm can be greater than about 2.5 cm, 5 cm, 7.5 cm, 10 cm, 12.5 cm, 15 cm, 17.5 cm, 20 cm, or greater. The shape of the pivot body 220 at the proximal end can be configured to provide this lever arm.

[0058] As shown in FIGs. 2A and 2B, a lower portion of the pivot body 220 can include a pump system housing 222 configured in size and shape to receive the pump system 300. The pump housing 222 may provide a recess into which the pump system 300 is received, for example, in the manner described below in relation to FIGs. 5A-5C. As noted above, in some embodiments, the pump system 300 is removably received in the recess of the pump housing 222, while in other embodiments, the pump system 300 is permanently received (e.g., non-removably received) therein.

[0059] The pump housing 222 is configured so as to orient the water exhaust 306 of the pump system 300 in a direction that is generally aligned with the paddle 202. By forming the pump housing 222 on the pivot body 220, the pump system 300 pivots with the fishtail propulsion assembly 200.

[0060] A distal end of the pivot body 208 attaches to the paddle 202. In the illustrated embodiment, the pivot body 208 is configured to generally decrease in width to match the width of the paddle 202 and to maintain a hydrodynamic shape. While this may be advantageous, it is not necessary in all embodiments.

[0061] The paddle 202 can be made of a flexible material. In some embodiments, the paddle 202 is uniformly flexible. In some embodiments, the paddle 202 becomes increasingly flexible moving from its proximal edge to its distal edge. That is, in some embodiments, the distal portion of the paddle 202 may be more flexible than a proximal portion. Variation in flexibility can be achieved in many ways. As one example, the thickness of the paddle 202 may be decrease to provide increased flexibility. In some embodiments, various materials with different flexural properties can be used to vary flexibility. In some embodiments, ribs, grooves, slots, holes, or other structures can be formed into the paddle 202 to vary the flexibility in various regions. In some embodiments, various supports (e.g., rods, meshes, or other reinforcing structures) can be placed into the paddle 202 to vary the flexibility.

[0062] As noted above, a flexible paddle may mimic the way in which a fish swims. For example, as a fish tail swishes to the right the flexible tail bends left, storing energy that is released when the tail begins to swish left. The paddle 202 can, in some embodiments, operate in a similar manner. The energy stored in the flexed paddle 202 during operation may increase the propulsive force provided by the fishtail propulsion system 200.

[0063] FIGs. 3A and 3B are top and bottom perspective views of an embodiment of a fishtail propulsion system 200b that is configured for use with a personal w'atercraft. The fishtail propulsion system 200b of FIGs. 3 A and 3B is similar to the fishtail propulsion system 200 of FIGs. 2A and 2B, except that it does not include a pump housing 222 for housing a pump system 300. Thus, FIGs. 3A and 3B, illustrate that, in some embodiments, the fishtail propulsion system 200b need not include a pump system 300.

[0064] As noted with respect to FIGs. 3A and 3B, in some embodiments, the fishtail propulsion system 200 need not include a pump system 300. In such cases, the pump system 300 can be entirely omitted from the personal watercraft 100, or, as shown in FIGs. 4A and 4B, the pump system 300 can be configured to be received (either permanently or removably) into the hull 102 of the personal watercraft 100.

[0065] FIG. 4A is a bottom perspective view of an embodiment of the personal watercraft 100 that includes a recess 125 formed in an underside of the hull 102 thereof. The recess 125 can be configured to receive the pump system 300 for propelling the personal watercraft 100.

[0066] FIG. 4B is a bottom perspective view of the underside portion of the hull 102 of the personal watercraft 100. In the illustrated example, the pump system 300 for propelling the personal watercraft is received within the recess 125. As shown, the pump body 302 is positioned within the recess 125 formed on the underside of the hull 102. The pump system 300 is configured to intake water through a water intake 304 and accelerate it out though a water exhaust 306 to provide a propulsive force. [0067] Although not illustrated, the personal watercraft of FIGs. 4A and 4B can include a fishtail propulsion system as illustrated in either FIGs. 2A and 2B or FIGs. 3A and 3B.

[0068] FIGs. 5A-5C depict a pump system 1000 configured to be placed within a recess 1106 of a personal watercraft. The pump system 1000 may be used as any of the pump systems 300 described above. The recess 1106 described with reference to FIGs. 5A-5C can be a recess in the fishtail propulsion system 200, such as is shown in FIGs. 1A-1E or 2A and 2B, or the recess 125 in the hull 102 of FIG.s 4A and 4B. FIG. 5A is an exploded side view of an embodiment of the pump system 1000 and corresponding recess 1106. FIG. 5B is a perspective view of the pump system 1000 and corresponding recess 1106 shown prior to insertion of the pump system into the recess. FIG. 5C is a perspective view of the pump system 1000 and corresponding recess 1106 shown after insertion of the pump system into the recess.

[0069] As illustrated, for some embodiments, the pump system 1000 includes a hatch 1002, a power unit body 1008, a motor 1006, motor contacts 1004, a drive shaft 1012, a shaft cover 1010, an impeller 1014, a flow straightener 1016, and a pump nozzle 1018. The hatch 1002 can connect to the power unit body 1008 through a snap fit, friction fit, bonding, or other mechanical means. In some embodiments, the connection between the hatch 1002 and the power unit body 1008 forms a watertight seal that prevents water from entering inside the hatch 1002 or power unit body 1008.

[0070] Installed inside the power unit body 1008 is the motor 1006. The motor may be sealed between the power unit body 1008 and the hatch 1002 when the hatch 1002 is installed on the power unit body 1008. The shaft cover 1010 may connect to the lower section of power unit body 1008. The shaft cover 1010 can form a watertight seal with the power unit body 1008 so as to prevent water from entering inside the power unit body 1008. The drive shaft 1012 may be configured to be installed within the shaft cover 1010.

[0071] The drive shaft 1012 connects to the motor 1006. In some embodiments, the drive shaft 1012 connects to the motor 1006 by being installed in a direct drive arrangement with the motor 1006. In other embodiments, the drive shaft 1010 connects to the motor 1006 through a gearbox or belt system. In some embodiments, the drive shaft 1012 can contain one or more O-ring or other sealant placed on the outer half of the drive shaft. The O-ring or sealant can prevent water from entering inside the power unit body 1008 through the inside of the shaft cover 1010. Connected to the end of the drive shaft 1012 is an impeller 1014.

[0072] The impeller 1014 can be installed on the end of the drive shaft 1012 through several mechanical means, including, for example, threading onto the drive shaft, bonding, welding, snap fit, or friction fit. In some embodiments, the impeller 1014 is an axial impeller. In some embodiments, the impeller 1014 has a symmetrical design, where the blades of the impeller 1014 are symmetrical about the centerline. This symmetrical design allows the blades of the impeller 1014 to create the same flow' pattern no matter which side of the impeller 1014 is mounted to the drive shaft 1012. The flow' straightener 1016 is installed on one end of the impeller 1014. In some embodiments, the flow straightener does not contact the impeller 1014 when installed within the pump system 1000. In some of these embodiments, the flow straightener 1016 is positioned within the power unit body 1008. In other embodiments, the flow straightener 1016 is installed within the pump nozzle 1018. The pump nozzle 1018 connects to the power unit body 1008. In some embodiments, the pump nozzle 1018 is installed on a lower end of the power unit body 1008.

[0073] The pump system 1000 may use other components as well. For example, the power unit body 1008 can further house a motor controller, one or more batteries, an air pump, a wireless receiver, a wireless transmitter, one or more motor control systems, battery control systems, and/or sensors (including water sensors), among other components.

[0074] The pump system 1000 can be installed inside a recess 1106 of a personal watercraft or fishtail propulsion system and include a recess wall 1100. The recess wall 1100 is sized and shaped in a manner that allows for the pump system 1100 to be placed within the recess 1106 so that bottom section of the power body unit 1008 is about flush with the recess 1106. Once positioned within the recess 1106, the pump system 1000 can be held in place through various mechanical and chemical means, including, for example, clamps, fasteners, bonding, welding, friction fit, or snap fit. In some embodiments, a mounting plate is used to mount and hold the pump system 1000 in place. Once installed, the pump system 1000 can form a watertight seal with the recess wall 1100 so as to prevent water from entering into the recess 1106.

[0075] In some embodiments, a grate can be placed over the front compartment

1020. The grate can have one or more (for example, 2, 3, 4, 5, 6, 7, 8, 9, 10, or more) bars extending across the front compartment 1020. The grate can prevent or restrict debris from entering into the pump system 1000 while still permitting water to enter into the pump system 1000.

[0076] The motor contacts 1004 can contact and form a connection with the motor controller 1102. The motor controller 1102 can be accessible to a user of the personal watercraft while the user is seated therein. In some embodiments, the user will need to remove an access hatch to access the motor controller 1102. In other embodiments, the motor controller 1102 is readily accessible to the user without the user needing to remove or open any additional equipment. The motor controller 1102 can be connected to an external battery through a set of cables 1104. Because the external battery is connected to the cables 1104, the external battery can be installed within the personal watercraft at multiple locations, including locations that allow the external battery to be easily accessible by the user. In some embodiments, a user can replace the external battery without having to uninstall any part of the pump system 1000. The external battery can be used to power the motor 1006. Once the external battery is installed, the motor controller 1102 can distribute power to the motor 1006.

[0077] The pump system 1000 operates by drawing water in through the front compartment 1020 on the power unit body 1008. Water is drawn into the front compartment 1020 due to the motor 1006 driving the impeller 1014. In some embodiments, the impeller 1014 reduces the pressure of the water, creating suction downstream of the impeller 1014 (e.g. creates suction near the front compartment 1014). Reducing the water pressure draws the water through the front compartment 1020 and into the power unit body 1008. The water drawn into the front compartment 1020 travels over the impeller 1014, which assists with moving the water through the pump system 1000. After the water travels over the impeller 1014, the water travels over the flow straightener 1016, causing the water to form a laminar flow (e.g. the flowstraightener reduces or removes the spin on the water created by the impeller). The water then exits the pump system 1000 at the pump nozzle 1018, creating a jet of water that propels the kayak 1300 forward. In some embodiments, water can be drawn in through the pump nozzle 1018 and expelled out of the front compartment 1020. In some of these embodiments, the motor 1006 can spin the impeller 1014 in the opposite direction of normal operation. Spinning the impeller 1014 in the opposite direction can lower the water pressure on the opposite side of the impeller 1014 (e.g. on the side near the pump nozzle 1018), causing wrater to be drawn in through the pump nozzle 1018 and directed to the front compartment 1020. This reverse flow creates thrust in the reverse direction, propelling the watercraft in the aft direction. The pump system 1000 can be controlled through the motor controller 1102. In some embodiments, the motor controller 1102 can be configured to control the pump system 1000 in a manner as described with other embodiments herein. For example, the motor controller 1102 may be configured to activate or deactivate the motor 1006, control the speed of the motor 1006 and/or the amount of power supplied to the motor 1006, and/or control other motor 1006 functions. By adjusting the power of the motor 1006, a user can adjust the thrust a pump system 1000 produces. The motor 1006 can receive power through an external power source, such as an external battery. The external battery can be connected to the pump system 1000 through cables 1104.

[0078] In some embodiments, the recess 1106 can have sidewalls and a base. For example, the recess 1106 can form a V-shape or U-shape profile on the end near the pump nozzle 1018. This profile can increase thrust by constricting water as it exits the pump nozzle 1018. In some embodiments, water may be expelled from the pump nozzle 1018 towards the sloped area of the recess 1106 to create a Coanda Effect.

[0079] In some embodiments, the pump nozzle 1018 can have an oval-shaped end. The oval-shaped end can be similar to the oval-shaped end 815 described herein in both size and function. For example, the oval-shaped end can increase thrust from water expelled from the pump nozzle 1018. The oval-shaped end can operate as a nonintrusive flow straightener. As a result, the water expelled from the pump nozzle 1018 forms a tight rope and maintains the tight rope shape over a long distance (for example, about 25 feet). By creating a tight rope of water that holds its shape over long distances, the pump nozzle 1018 can increase the thrust and efficiency from the pump system 1000. In some embodiments, the pump nozzle 1018 has a constricted end (e.g. one end is narrower than the other end). The constricted end can increase the acceleration of the water as it flows out of the pump nozzle 1018.

[0080] In some embodiments, the pump system 1000 can powered by compressed air. In some of these embodiments, the motor 1006 is a pneumatic motor which can be powered by air. The cables 1104 can connect to an air tank and the motor controller 1102 can assist with regulating air flow to the motor. In some embodiments, a second pump system 1000 can be installed on base of the watercraft. The second pump system 1000 can function substantially similar to the first pump system 1000.

[0081] FIG. 6 is a side view of an embodiment of a personal watercraft 100 including an embodiment of a fishtail propulsion system 200 that is operable with a tiller 230. The tiller 230 can be connected to the fishtail propulsion system at the pivot point such that the tiller can be moved right and left to cause a corresponding rotation of the fishtail propulsion system. In this manner the tiller 230 can be operated to steer or propel the watercraft by moving the paddle 202.

[0082] In the foregoing specification, the invention has been described with reference to specific embodiments thereof. It will, however, be evident that various modifications and changes may be made thereto without departing from the broader spirit and scope of the invention. The specification and drawings are, accordingly, to be regarded in an illustrative rather than restrictive sense.

[0083] Indeed, although this invention has been disclosed in the context of certain embodiments and examples, it will be understood by those skilled in the art that the invention extends beyond the specifically disclosed embodiments to other alternative embodiments and/or uses of the invention and obvious modifications and equivalents thereof. In addition, while several variations of the embodiments of the invention have been shown and described in detail, other modifications, which are within the scope of this invention, will be readily apparent to those of skill in the art based upon this disclosure. It is also contemplated that various combinations or sub-combinations of the specific features and aspects of the embodiments may be made and still fall within the scope of the invention. It should be understood that various features and aspects of the disclosed embodiments can be combined with, or substituted for, one another in order to form varying modes of the embodiments of the disclosed invention. Any methods disclosed herein need not be performed in the order recited. Thus, it is intended that the scope of the invention herein disclosed should not be limited by the particular embodiments described above.

[0084] It will be appreciated that the systems and methods of the disclosure each have several innovative aspects, no single one of which is solely responsible or required for the desirable attributes disclosed herein. The various features and processes described above may be used independently of one another or may be combined in various ways. All possible combinations and sub-combinations are intended to fell within the scope of this disclosure.

[0085] Certain features that are described in this specification in the context of separate embodiments also may be implemented in combination in a single embodiment. Conversely, various features that are described in the context of a single embodiment also maybe implemented in multiple embodiments separately or in any suitable subcombination. Moreover, although features may be described above as acting in certain combinations and even initially claimed as such, one or more features from a claimed combination may in some cases be excised from the combination, and the claimed combination may be directed to a subcombination or variation of a subcombination. No single feature or group of features is necessary or indispensable to each and every embodiment.

[0086] It will also be appreciated that conditional language used herein, such as, among others, “can,” “could,” “might,” “may,” “e.g.,” and the like, unless specifically stated otherwise, or otherwise understood within the context as used, is generally intended to convey that certain embodiments include, while other embodiments do not include, certain features, elements and/or steps. Thus, such conditional language is not generally intended to imply that features, elements and/or steps are in any way required for one or more embodiments or that one or more embodiments necessarily include logic for deciding, with or without author input or prompting, whether these features, elements and/or steps are included or are to be performed in any particular embodiment. The terms “comprising,” “including,” “having,” and the like are synonymous and are used inclusively, in an open- ended fashion, and do not exclude additional elements, features, acts, operations, and so forth. In addition, the term “or” is used in its inclusive sense (and not in its exclusive sense) so that when used, for example, to connect a list of elements, the term “of’ means one, some, or all of the elements in the list In addition, the articles “a," “an,” and “the” as used in this application and the appended claims are to be construed to mean “one or more” or “at least one” unless specified otherwise. Similarly, while operations may be depicted in the drawings in a particular order, it is to be recognized that such operations need not be performed in the particular order shown or in sequential order, or that all illustrated operations be performed, to achieve desirable results. Further, the drawings may schematically depict one more example processes in the form of a flowchart. However, other operations that are not depicted may be incorporated in the example methods and processes that are schematically illustrated. For example, one or more additional operations may be performed before, after, simultaneously, or between any of the illustrated operations. Additionally, the operations may be rearranged or reordered in other embodiments. In certain circumstances, multitasking and parallel processing may be advantageous. Additionally, other embodiments are within the scope of the following claims. In some cases, the actions recited in the claims may be performed in a different order and still achieve desirable results.

[0087] Further, while the methods and devices described herein may be susceptible to various modifications and alternative forms, specific examples thereof have been shown in the drawings and are herein described in detail. It should be understood, however, that the invention is not to be limited to the particular forms or methods disclosed, but, to the contrary, the invention is to cover all modifications, equivalents, and alternatives falling within the spirit and scope of the various implementations described and the appended claims. Further, the disclosure herein of any particular feature, aspect, method, property, characteristic, quality, attribute, element, or the like in connection with an implementation or embodiment can be used in all other implementations or embodiments set forth herein. Any methods disclosed herein need not be performed in the order recited. The methods disclosed herein may include certain actions taken by a practitioner; however, the methods can also include any third-party instruction of those actions, either expressly or by implication. The ranges disclosed herein also encompass any and all overlap, sub-ranges, and combinations thereof. Language such as “up to," “at least," “greater than," “less than," “between," and the like includes the number recited. Numbers preceded by a term such as “about" or “approximately" include the recited numbers and should be interpreted based on the circumstances (e.g., as accurate as reasonably possible under the circumstances, for example ±5%, ±10%, ±15%, etc.). For example, “about 3.5 mm" includes “3.5 mm." Phrases preceded by a term such as “substantially" include the recited phrase and should be interpreted based on the circumstances (e.g., as much as reasonably possible under the circumstances). For example, “substantially constant" includes “constant." Unless stated otherwise, all measurements are at standard conditions including temperature and pressure.

[0088] As used herein, a phrase referring to “at least one of’ a list of items refers to any combination of those items, including single members. As an example, “at least one of: A, B, or C” is intended to cover: A; B; C; A and B; A and C; B and C; and A, B, and C. Conjunctive language such as the phrase “at least one of X, Y and Z,” unless specifically stated otherwise, is otherwise understood with the context as used in general to convey that an item, term, etc. may be at least one of X, Y or Z. Thus, such conjunctive language is not generally intended to imply that certain embodiments require at least one of X, at least one of Y, and at least one of Z to each be present. The headings provided herein, if any, are for convenience only and do not necessarily affect the scope or meaning of the devices and methods disclosed herein.

[0089] Accordingly, the claims are not intended to be limited to the embodiments shown herein, but are to be accorded the widest scope consistent with this disclosure, the principles and the novel features disclosed herein.