Propulsion device for watercraft

1. A propulsion mechanism adapted to be inserted in an opening in the bottom of a watercraft comprising a pair of flexible fins extending below the water line, said pair of flexible fins each adapted to oscillate through an arcuate path on a horizontal shaft to propel the watercraft, said horizontal shaft being continuously rotatable in either direction about a generally vertical shaft to propel said watercraft in any direction in a generally horizontal plane, whereby as input force is applied to said pair of flexible fins, said pair of flexible fins can twist to form an angle of attack for providing thrust while moving in both directions along said arcuate path.

2. The propulsion mechanism of claim 1 wherein upper cables couple each of said pedals to bearing ring assemblies, each bearing ring assembly comprising an upper non-rotatable ring and a lower rotatable ring, said upper cables being coupled to said upper rings, and lower cables coupling said lower rings to said horizontal shaft to oscillate said fins, said lower cables and bearing ring assemblies reciprocating in alignment with said vertical shaft by input force to said pedals, one bearing ring assembly passing freely through said other bearing ring assembly.

3. The propulsion mechanism of claim 2 wherein each pedal operates two cables, one cable coupling to one said upper non-rotatable ring and the other cable coupling to the other said upper non-rotatable ring, and two lower cables coupling one said lower rotatable ring to said horizontal shaft, and two lower cables coupling said other lower rotatable ring to said horizontal shaft.

4. The mechanism of claim 3 wherein said horizontal shaft comprises a horizontal shaft carrying two drums oscillatable on said shaft, each drum carrying one of said fins, two of said lower cables attached to opposed sides of each of said drums.

5. A watercraft comprising a propulsion mechanism extending through an opening in the bottom of the watercraft, said propulsion mechanism comprising a pair of flexible fins extending below the water line, said pair of flexible fins each adapted to oscillate through an arcuate path on a horizontal shaft to propel the watercraft, said horizontal shaft being continuously rotatable in either direction about a generally vertical shaft to propel said watercraft in any direction in a generally horizontal plane, whereby as input force is applied to said pair of flexible fins, said pair of flexible fins can twist to form an angle of attack for providing thrust while moving in both directions along said arcuate path.

6. The watercraft of claim 5 having a cockpit, a steering handle adjacent said cockpit operable by an occupant of said cockpit, said steering handle being coupled to said vertical shaft to rotate said horizontal shaft.

7. The watercraft of claim 5 wherein the watercraft is a kayak.

8. The watercraft of claim 6 wherein a direction indicator is disposed so as to be visible from said cockpit, said direction indicator is coupled to said vertical shaft.

9. A propulsion mechanism adapted to be inserted in an opening in the bottom of a watercraft comprising a pair of flexible fins extending below the water line, said pair of flexible fins each adapted to oscillate through an arcuate path on a horizontal shaft to propel the watercraft, said horizontal shaft being continuously rotatable in either direction about a generally vertical shaft to propel said watercraft in any direction in a generally horizontal plane, and a pair of pedals coupled to said pair of flexible fins for applying input force whereby as input force is applied, said pair of flexible fins can twist to form an angle of attack for providing thrust while moving in both directions along said arcuate path.

10. A watercraft comprising a propulsion mechanism extending through an opening in the bottom of the watercraft, said propulsion mechanism comprising a pair of flexible fins extending below the water line, said pair of flexible fins each adapted to oscillate through an arcuate path on a horizontal shaft to propel the watercraft, said horizontal shaft being continuously rotatable in either direction in a generally horizontal plane about a generally vertical shaft to propel said watercraft in any direction, and a pair of pedals coupled to said pair of flexible fins for applying input force whereby as input force is applied, said pair of flexible fins can twist to form an angle of attack for providing thrust while moving in both directions along said arcuate path.

11. A propulsion mechanism adapted to be inserted in an opening in the bottom of a watercraft comprising a pair of flexible fins extending below the water line, said pair of flexible fins each adapted to oscillate through an arcuate path on a horizontal shaft to propel the watercraft, said horizontal shaft being continuously rotatable in either direction about a generally vertical shaft to propel said watercraft in any direction in a generally horizontal plane, said vertical shaft being remotely controlled from within the watercraft to steer the watercraft in any direction while being pedaled, and a pair of pedals coupled to said pair of flexible fins for applying input force whereby as input force is applied, the pair of flexible fins can twist to form an angle of attack for providing thrust while moving in both directions along the arcuate path.

12. A watercraft comprising a propulsion mechanism extending through an opening in the bottom of the watercraft, said propulsion mechanism comprising a pair of flexible fins extending below the water line, said pair of flexible fins each adapted to oscillate through an arcuate path on a horizontal shaft to propel the watercraft, said horizontal shaft being continuously rotatable in either direction about a generally vertical shaft to propel said watercraft in any direction in a generally horizontal plane, said vertical shaft being remotely controlled by elements operable from within the watercraft to steer the watercraft in any direction while being pedaled, and a pair of pedals coupled to said pair of flexible fins for applying input force whereby as input force is applied, said pair of flexible fins can twist to form an angle of attack for providing thrust while moving in both directions along the arcuate path.

13. A watercraft comprising a propulsion mechanism extending through an opening in the bottom of the watercraft, said propulsion mechanism adapted to rotate about a generally vertical shaft and being steered from within the watercraft to rotate said propulsion mechanism in any direction in a generally horizontal plane, a clutch coupled to said vertical shaft operable to lock said vertical shaft in position to resist rotational torque and to allow rotation when actively steered from within said watercraft, and a pair of pedals coupled to the propulsion mechanism for applying input force whereby as input force is applied thrust is produced.

14. The watercraft of claim 13 wherein said pair of pedals are coupled to a pair of flexible fins whereby as input force is applied, said pair of flexible fins can twist to form an angle of attack for providing thrust while moving in both directions across an arcuate path.

15. The watercraft of claim 14 wherein said pair of pedals are operatively coupled with a pair of flexible fins for applying input force wherein as input force is applied, said pair of flexible fins can twist to form an angle of attack for providing thrust while moving in both directions across an arcuate path and said clutch being attached to said watercraft and adapted to slip in the event said pair of flexible fins are over-forced.

16. A propulsion mechanism adapted to be inserted in an opening in the bottom of a watercraft comprising a pair of flexible fins extending below the water line, said pair of flexible fins each adapted to oscillate through an arcuate path on a horizontal shaft to propel the watercraft, said horizontal shaft being continuously rotatable through about 90° left and right about a generally vertical shaft to propel said watercraft in any direction in a generally horizontal plane, whereby as input force is applied to said pair of flexible fins, said pair of flexible fins can twist to form an angle of attack for providing thrust while moving in both directions along said arcuate path.

17. A watercraft comprising a propulsion system extending through an opening in the bottom of said watercraft, said propulsion mechanism comprising a pair of flexible fins extending below the water line, said pair of flexible fins each adapted to oscillate through an arcuate path on a horizontal shaft to propel the watercraft, said horizontal shaft being continuously rotatable through about 90° left and right about a generally vertical shaft to propel said watercraft in any direction in a generally horizontal plane, whereby as input force is applied to said pair of flexible fins, said pair of flexible fins can twist to form an angle of attack for providing thrust while moving in both directions along said arcuate path.