Buoys – rafts – and aquatic devices – Water skimming or walking device – Having stabilizing surface
Reexamination Certificate
2001-04-24
2002-08-27
Morano, S. Joseph (Department: 3617)
Buoys, rafts, and aquatic devices
Water skimming or walking device
Having stabilizing surface
C441S074000, C114S152000
Reexamination Certificate
active
06439940
ABSTRACT:
FIELD OF INVENTION
The invention pertains to stabilizing fins for use with watercraft. More particularly, the invention relates to movable fins for use with surfboards, windsurfers, kite surfers and boats.
BACKGROUND OF THE INVENTION
Various designs for fins, both fixed and movable have been developed for use with surfboards and other watercraft. Movable fins provide allow for enhanced directional guidance associated with multiple fin systems while permitting reduced water resistance during turns. U.S. Pat. No. 6,053,789 issued to Miyashiro discloses a limited pivotal fin system for a surfboard. The system includes an upper stationary mounting portion attached to the underside of the surfboard, and a lower pivoting fin with a limited rotational pivoting mechanism located in an upper recessed area on the leading edge of the pivoting fin.
U.S. Pat. No. 4,811,674 issued to Stewart, describes a foil arrangement for water-borne craft in which the hull of the watercraft includes a pair of tiltable foils disposed at the stern of the craft at either side of the centerline. The foils tilt outwardly when the watercraft is moving straight ahead, causing the rear of the craft to lift, thus reducing hydrodynamic drag and increasing speed. The foils tilt downwardly and inwardly in turns, acting as an extra fin and serving to tighten the turn of the watercraft.
U.S. Pat. No. 4,854,904, issued to Wahl discloses a sailboard with an adjustable keel mechanism. The keel is capable of pivoting about a vertical axis located rearwardly from the center of the keel. The keel is forced by the flow of oncoming water to rotate in the windward direction from its centered position. A spring-loaded detent may be employed to return the keel to its centered position.
U.S. Pat. No. 4,733,496 issued to Wallner illustrates a pivoting surfboard fin that includes a rudder-like section that swings out when a turn is commenced, enhancing the maneuverability of the surfboard by redirecting the water flow through the pivoting rudder section in the direction of the turn. The fin employs a spring-loaded pin traveling in a tapered channel, which channel is deepest at the centerline of the fin, to center the rudder-like section of the fin.
U.S. Pat. No. 3,890,661 issued to Johnson discloses a surfboard rudder-fin combination that permits the surfer to vary the angle of the fin with respect to the surfboard by shifting his weight on the board. A spring-loaded lever arm is employed to control the degree of rotation of the fin. While other variations exist, the above-described designs for movable watercraft fins, rudders and foils are typical of those encountered in the prior art.
It is an objective of the present invention to provide a fin system for watercraft that will permit tighter turning and improve maneuverability of the craft by providing at least one fin that will resist maneuvering forces while permitting an opposing fins to “feather” or turn so as not to oppose the oncoming flow, thus minimizing drag from inactive fin. It is a further objective to provide a system that avoids unnecessary drag when the watercraft moves in a downwind direction by permitting fins on either side of the watercraft to automatically assume an orientation that minimizes resistance to the water flow beneath the craft. It is yet a further objective to permit the user of the system to adjust the limits of the arc through which the fin may rotate. It is still a further objective to enhance the ability of wind-powered watercraft to move in an upwind direction. Finally, it is an objective of the invention to provide the above-described capabilities in an inexpensive and durable fin system that may be easily cleaned of sand and debris and that may be easily repaired and maintained.
While some of the features of the present invention are disclosed in the prior art, none of the inventions found satisfy all of the requirements identified.
SUMMARY OF THE INVENTION
The present invention addresses all of the deficiencies of prior art fin and watercraft inventions and satisfies all of the objectives described above.
A fin and watercraft system providing the desired features may be constructed from the following components. A watercraft is provided. The watercraft has a front end, a rear end, a midpoint between the front end and the rear end, a lower surface, an upper surface, first and second sides and a centerline between the first and second sides. At least one pair of fins is provided. The pair of fins includes a first side fin and a second side fin. The pair of fins is located between the midpoint and the rear end of the watercraft, equidistant from the centerline and equidistant from the rear end.
The first side fin is located adjacent the first side of the watercraft and the second side fin is located adjacent the second side. Each of the first and second side fins has a top end, a bottom end, a leading edge, a trailing edge and a vertical axis. A horizontal axis extends from the leading edge to the trailing edge of the fin. A front portion of the fin extends from the leading edge to the vertical axis. A rear portion of the fin extends from the vertical axis to the trailing edge. The fin includes and first and second lateral surfaces. Each of the first and second side fins is rotatably mounted about the vertical axis to the lower surface of the watercraft. The first side fin is rotatable from a first position to a second position. The second side fin is rotatable from a third position to a fourth position.
When the watercraft is forced to move in a direction parallel to its centerline, an oncoming flow of water beneath the watercraft will cause the first side fin and the second side fin to rotate to the first and third positions, respectively. When the watercraft is forced to move in a direction from the centerline toward its first side, the oncoming water flow will cause the first side fin to rotate to the second position and the second side fin to remain in the third position. When the watercraft is forced to move in a direction from the centerline toward its second side the oncoming water flow will cause the second side fin to rotate to the fourth position and the first side fin to remain in the first position.
In a variant of the invention, when the first side fin is located in the first position its horizontal axis is parallel to the centerline of the watercraft. When the second side fin is located in the third position its horizontal axis is parallel to the centerline of the watercraft. When the first side fin is located in the second position its horizontal axis is angled toward the centerline at between zero and ninety degrees to a position of the horizontal axis when the first side fin is located in the first position. When the second side fin is located in the fourth position its horizontal axis is angled toward the centerline at between zero and ninety degrees to a position of the horizontal axis when the second side fin is located in the third position.
In a further variant, when the first side fin is located in the first position its horizontal axis is angled toward the centerline of the watercraft at a fixed angle between zero and fifteen degrees. When the second side fin is located in the third position its horizontal axis is angled toward the centerline of the watercraft at a fixed angle between zero and fifteen degrees. When the first side fin is located in the second position its horizontal axis is angled toward the centerline at between zero and ninety degrees to a position of the horizontal axis when the first side fin is located in the first position. When the second side fin is located in the fourth position its horizontal axis is angled toward the centerline at between zero and ninety degrees to a position of the horizontal axis when the second side fin is located in the third position.
In yet another variant of the invention, the rear portion of each of the first and second side fins is larger than the front portion of the fins, causing the fins to rotate so as to align with a flow of oncoming water.
In still another var
Belasco David A.
Morano S. Joseph
Olson Lars A
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