The embodiments and aspects described herein are regarding a watercraft. Conventional watercraft rely on a low center of gravity, with a wide base relative to the height of the load, to avoid capsizing. However, a wide watercraft hull increases water resistance resulting in slower speeds and hampered maneuverability. On small watercraft with narrow hulls, occupants must remain positioned close to the waterline to avoid causing unstable equilibrium, which is restrictive for the occupants. Various watercraft with multiple spaced floats and front or rear steering have been proposed, but these are slow to change course, and water flow is impeded by the configuration of floats and steering elements, resulting in lowered top speeds. Other attempts at watercraft with narrow single hulls and a high center of gravity had no effective way to stay upright, particularly at low speeds. Therefore, there is a need for a different kind of watercraft which does not rely on a low center of gravity for stability, is easy to maneuver, and which moves through water with minimal resistance. An object of the invention is an agile watercraft with an active and intuitive method of maintaining balance.
The invention provides an apparatus for water transport, recreation, exercise and sport which is responsive and easy to maneuver. It is herein referred to as a watercraft. The watercraft comprises two or more flotation elements aligned fore and aft, a fore flotation element capable of pivoting about an axis. Adjacent ends of the flotation elements fit together to minimize turbulence and water resistance. The pivoting steering axis of the fore flotation element is tilted aft of vertical toward the watercraft occupants. Pivotal movements of the fore flotation element shifts the transverse center of gravity to maintain balance. The shape of the front flotation element and the angle of the pivot axis effect the amount of weight shift caused by pivotal movements. Changes in weight distribution caused by movement of the pivot axis alone are maximized when the pivot axis of the watercraft is fixed at 45 degrees to the waterline, which is midway between vertical and horizontal. Watercraft use, design and speed are factors which determine the amount of weight shift affect which is desirable, and the pivot axis is therefore set at different angles relative to the waterline in various embodiments of the invention.
In a preferred embodiment, the watercraft is ridden in a manner similar to riding a bicycle. Riders who are positioned principally above the gunwales of the watercraft can easily maintain balance. When the fore flotation element of the watercraft is turned to the right or left, weight is shifted laterally to the opposite side of the watercraft due to the shape of the fore flotation element and the angle at which it pivots. When the watercraft tilts to either side, a rider is able to avoid tipping over by turning the bow of the watercraft in the same direction that the watercraft is tilting, thereby shifting the transverse center of gravity back toward the center of the watercraft to counter the tipping motion. Balancing in this manner feels familiar to anyone who is proficient at riding a bicycle and it is therefore easy for operators of the watercraft to accomplish. Balance can be easily maintained by the rider when the watercraft is stationary as well as when the watercraft is in motion by making quick steering adjustments.
In a preferred embodiment, a front rudder projects from the longitudinal center line of the bottom of the fore flotation element. The rudder is rigidly connected to the fore flotation element and the rudder turns with the fore flotation element. The rudder is positioned proximal to the pivotal axis of the fore flotation element which allows for easy and effective steering. A portion of the rudder blade is optionally located aft of the center of said axis. When turning, this counters an initial opposing motion caused by a sweeping movement of the watercraft bow. The position of the rudder also assists the operator when steering the watercraft in a predominately straight path.
Quick, responsive turns of the watercraft can be performed using the pivotal fore flotation element and connected rudder. In a preferred embodiment, depth of the rudder blade is manually adjustable and a latch connected to a cable can be operated by the watercraft operator to release the rudder if desired when shallow water is encountered and when the watercraft is brought to shore. The rudder is removable for transport.
In a preferred embodiment, a propeller is rotatably connected to an out drive unit which includes a plurality of pulleys, bearings and a drive belt. The out drive unit is attached to the aft end of the watercraft and optionally capable of pivoting in and out of the water when landing on shore, or otherwise desired. The out drive unit is rotatably connected to a drivetrain by a sprocket. The drivetrain provides locomotion. In this embodiment, the watercraft is manually powered by foot pedals rotatably connected to crank arms on the drivetrain. The drivetrain comprises a plurality of sprockets, roller chains, bearings and axles rotatably connected to a bicycle frame, or a plastic and fiber composite or metal frame of similar construction.
The included drawings show ways to accomplish the invention, but the scope of the invention is not limited by the illustrations.
In a preferred embodiment illustrated in
The fork assembly 6 is rigidly attached to adjustable brackets 26 on a fore flotation element 28 which is located forward of the main flotation element 2. The fore flotation element 28 is constructed of plastic, or plastic and fiber composite materials, with optional metal reinforcement. The lower end of a support 32 is adjustably attached to a surface bracket 34 mounted on the top deck of the fore flotation element 28. The upper end of the support 32 is removably attached to a bracket 36 mounted on the handlebar stem riser 12. The bicycle frame 4 is supported by an adjustable brace 38 that is attached to the main flotation element 2.
The functional shape of the combined hull of the watercraft changes whenever the fore flotation element 28 is rotated out of linear alignment with the main flotation element 2, thereby tilting the watercraft toward the outside of each turn. The term combined hull herein refers to the combined lower exterior portions of flotation elements which form the buoyant body of the watercraft.
The shape of the aft end of the fore flotation element 28 matches the shape of the adjacent end of the main flotation element 2, forming a pivotal joint. In a preferred embodiment illustrated in
In
A front rudder 74 extends through a slotted opening in the bottom of the fore flotation element 28. Watertight inner walls separate the slotted opening from the inner cavity of the fore flotation element 28. The rudder 74 is proximal to the pivot axis of the fore flotation element 28 to minimize turning resistance. The rudder 74 combined with the pivotal fore flotation element 28 is capable of executing quick changes in direction. The ability to make responsive directional changes improves recreational enjoyment and ease of operation.
A portion of the blade of the rudder 74 is located aft of the steering pivot axis to improve tracking and counter an initial opposing force when turning. Turning the submerged portion of the bow section of the watercraft would otherwise initially push the watercraft in the opposite direction of the turn. The location of the rudder 74 makes for smooth turns and intuitive steering.
A rudder latch bolt release 76 is connected to the latch release control handle 14 by a cable line 78.
A head tube 82 is an integral part of the conventional bicycle frame 4. The fork assembly 6 is pivotally connected to the head tube 82. Conventional bicycle frames are commonly manufactured in a range of sizes and with the top of the head tube tilted aft of vertical at different angles for different uses. To accommodate varying bicycle frame sizes and design, rear mounting brackets 84 which are rigidly attached to the main flotation element 2 and adjustably attached to the rear fork ends of the bicycle frame 4 may be adjusted, the adjustable brackets 26 on the fore flotation element 28 may be adjusted, the adjustable support 32 may be moved in the adjustment plate 34, and the brace 38 may be moved up or down. The angle of the head tube 82 relative to the watercraft can be adjusted to the appropriate steering axis angle for the watercraft by raising or lowering the aft end of the bicycle frame 4 on the rear mounting brackets 84.
The main flotation element 2 and the fore flotation element 28 are optionally and detachably connected together by an adjustable swivel coupling 85. The swivel coupling 85 in a preferred embodiment shown in
Removable, buoyant plastic segments 89 are attached horizontally on each exterior lateral side of the main flotation element at the approximate waterline. The plastic segments 89 provide additional buoyancy when the normal waterline is exceeded on either side or both sides of the watercraft.
A horizontal plate 90 is optionally and rigidly attached to the bottom of the main flotation element 2 proximal to the stern. The horizontal plate 90 is wider than the remainder of the aft portion of the hull below waterline. The horizontal plate 90 increases hydrodynamic lift as speed increases without significantly increasing hydraulic resistance. At slower speeds lift is derived primarily by water displacement.
As illustrated in
When climbing aboard the watercraft from a body of water, the operator can stabilize the watercraft by fully rotating the bow of the fore flotation element 28 in the direction of the operator, which increases the lateral dimension of the hull and tilts the watercraft away from the operator, thereby counter balancing the weight of the operator while boarding.
As illustrated in
In an alternate embodiment, the support 32 is replaced with a plurality of adjustable supports, and the adjustable surface bracket 34 is replaced with a plurality of surface brackets.
In an alternate embodiment, the roller chain 52 is replaced by a belt, the large sprocket 46 is replaced by a pulley, and the rear sprocket 54 is replaced by a pulley.
In an alternate embodiment, a rear bicycle wheel replaces the large sprocket 46. In this embodiment, the roller chain 52 and the rear sprocket 54 are replaced by rollers.
In an alternate embodiment, the upper pulley 58 and the lower pulley 61 are replaced by sprockets, and the belt 60 is replaced by a roller chain.
In an alternate embodiment, the upper pulley 58, the lower pulley 61 and the belt 60 are replaced by a gear box with bevel gears.
In an alternate embodiment, the optional swivel coupling 85 between flotation elements comprises a ball and socket similar to a tow hitch coupler.
In an alternate embodiment, a motor replaces the manual drivetrain.
In an alternate embodiment, the bicycle frame 4 is replaced by a similar framework of metal, carbon, plastic or composite structural materials rigidly attached to the main flotation element 2, and the fork assembly 6 is replaced by a metal, plastic or composite structural member or members pivotally attached to the frame 4 and rigidly attached to the fore flotation element 28.
In an alternate embodiment, the upright bicycle frame 4 is replaced by a framework similar to a recumbent bicycle frame.
In an alternate embodiment, the front rudder 74 is hinged.
In an alternate embodiment, the front rudder 74 is replaced by a keel or bottom fin.
In an alternate embodiment, the front rudder 74 is replaced by a plurality of longitudinal bottom fins.
In an alternate embodiment illustrated in
In an alternate embodiment illustrated in
In an alternate embodiment illustrated in
In an alternate embodiment illustrated in
The scope of use for pivot joints formed by matching surfaces on adjacent flotation elements includes other types of watercraft beyond the watercraft described herein and said joints formed by matching surfaces on adjacent flotation elements may be used in combination.
In an alternate embodiment, the buoyant plastic segments 89 are integral to the hull, comprising a widening of the hull of the main flotation element 2 on each side immediately above and along the approximate water line.
In an alternate embodiment, the horizontal plate 90 is removable.
In an alternate embodiment, the chainring 20 is elliptical.
In an alternate embodiment, the large sprocket 46 is elliptical.
Optional changes may be made to the shape of the combined hull, the shape of flotation elements, the number of flotation elements, and the angle of the steering axis without altering the nature of the invention. Changes in hull length and profile may be made depending upon use and performance preferences without departing from the scope of the invention.
This application claims the benefit of U.S. provisional patent application No. 62/796,486; submitted Jan. 24, 2019; entitled, Watercraft with Collinear Flotation Components