Amphibious marsh craft

1. A tracked, amphibious vehicle, comprising:

a) at least two, spaced, elongated pontoons disposed generally parallel to one another in left and right positions;

b) a platform structure supported by and structurally connecting the pontoons, the platform structure including a transom, a lowermost generally horizontally extending panel above a free clearance area under a bottom panel and between the pontoons through which terrain and debris can pass;

c) a hydraulic drive system that propels the vehicle, said drive system including left and right hydraulic motors mounted on the pontoons, the left hydraulic motor mounted on the left pontoon, the right hydraulic motor mounted on the right pontoon;

d) at least one series of longitudinally spaced bogie wheels for supporting said vehicle mounted along a bottom of each of said pontoons;

e) a continuous, endless belt encircling each pontoon and engaging the bogie wheels;

f) ground-engaging cleats assembled on an outer surface of each belt and covering the pontoon bottom for providing traction to the vehicle;

g) wherein each of the left and right hydraulic motors interfaces with the endless belts; and

h) a supplemental, marine drive assembly that includes:

a marine drive assembly hydraulic motor having a rotary device, shaft, with an axis;

a propeller shaft having an axis;

wherein the marine drive assembly hydraulic motor axis and propeller shaft axis are aligned;

a universal joint that connects the marine drive assembly hydraulic motor to the platform structure;

wherein the universal joint includes an attachment that is on the platform structure;

a housing including a sleeve that contains the propeller shaft, a first plate connected to the sleeve and a second plate connected to the sleeve below the first plate.

2. The vehicle of claim 1 wherein said first and second plates define a plane.

3. The vehicle of claim 1 wherein the propeller is movable between a lower position below said horizontally extending panel and an upper position above said horizontally extending panel.

4. The vehicle of claim 1 wherein said sleeve is movable between a lower position below said horizontally extending panel and an upper position above said horizontally extending panel.

5. The vehicle of claim 1 further comprising a horizontal plate attached to said first plate.

6. The vehicle of claim 5 further comprising a cavitation plate attached to the first plate and the horizontal plate.

7. The vehicle of claim 6 further comprising an arm connected to the housing at the horizontal plate.

8. The vehicle of claim 7 wherein the arm attaches to the horizontal plate at a first position and to the housing at a second position that is behind the first position.

9. The vehicle of claim 1 further comprising an actuator that lifts and lowers the propeller and sleeve.

10. The vehicle of claim 1 further comprising an actuator that pivots the sleeve and propeller between port and starboard positions.

11. A tracked, amphibious vehicle, comprising:

a) at least two, spaced, elongated pontoons disposed generally parallel to one another in left and right positions;

b) a platform structure supported by and structurally connecting the pontoons, the platform structure including a transom, a lowermost generally horizontally extending panel above a free clearance area under a bottom panel and between the pontoons through which terrain and debris can pass;

c) a hydraulic drive system that propels the vehicle, said drive system including left and right hydraulic motors mounted on the pontoons, the left hydraulic motor mounted on the left pontoon, the right hydraulic motor mounted on the right pontoon;

d) at least one series of longitudinally spaced bogie wheels for supporting said vehicle mounted along a bottom of each of said pontoons;

e) a continuous, endless belt encircling each pontoon driven by the hydraulic drive system and engaging the bogie wheels;

f) ground-engaging cleats assembled on an outer surface of each belt and covering the pontoon bottom for providing traction to the vehicle;

g) wherein each of the left and right hydraulic motors interfaces with the endless belts; and

h) a supplemental, marine drive assembly that includes:

a marine drive assembly hydraulic motor having a rotary device, shaft, with an axis;

a propeller shaft having an axis;

wherein the marine drive assembly hydraulic motor axis and propeller shaft axis are aligned;

a universal joint that connects the marine drive assembly hydraulic motor to the platform structure;

wherein the universal joint includes an attachment that is on the platform structure;

a housing including a sleeve that contains the propeller shaft, a first plate connected to the sleeve and a second plate connected to the sleeve below the first plate.

12. The vehicle of claim 11 wherein said first and second plates define a plane.

13. The vehicle of claim 11 wherein the propeller is movable between a lower position and an upper position above said lower position.

14. The vehicle of claim 11 wherein said sleeve is movable between a lower position below said horizontally extending panel and an upper position above said horizontally extending panel.

15. The vehicle of claim 11 further comprising a horizontal plate attached to said first plate.

16. The vehicle of claim 15 further comprising a cavitation plate attached to the first plate and the horizontal plate.

17. The vehicle of claim 16 further comprising an arm connected to the housing at the horizontal plate.

18. The vehicle of claim 17 wherein the arm attaches to the horizontal plate at a first position and to the housing at a second position that is behind the first position.

19. The vehicle of claim 11 further comprising an actuator that lifts and lowers the propeller and sleeve.

20. The vehicle of claim 11 further comprising an actuator that pivots the sleeve and propeller between port and starboard positions.

21. A tracked, amphibious vehicle, comprising:

a) at least two, spaced, elongated pontoons disposed generally parallel to one another in left and right positions;

b) a platform structure supported by and structurally connecting the pontoons, the platform structure including a transom, a lowermost generally horizontally extending panel above a free clearance area under a bottom panel and between the pontoons through which terrain and debris can pass;

c) a hydraulic drive system that propels the vehicle, said drive system including left and right hydraulic motors mounted on the pontoons, the left hydraulic motor mounted on the left pontoon, the right hydraulic motor mounted on the right pontoon;

d) at least one series of longitudinally spaced bogie wheels for supporting said vehicle mounted along a bottom of each of said pontoons;

e) a continuous, endless belt encircling each pontoon and engaging the bogie wheels;

f) ground-engaging cleats assembled on an outer surface of each belt and covering the pontoon bottom for providing traction to the vehicle;

g) wherein each of the left and right hydraulic motors interfaces with a said endless belt; and

h) a supplemental, marine drive assembly that includes:

a marine drive assembly hydraulic motor having a rotary device, shaft, with an axis;

a propeller shaft having an axis;

wherein the marine drive assembly hydraulic motor axis and propeller shaft axis are aligned;

a joint that connects the marine drive assembly hydraulic motor to the platform structure;

wherein the joint includes an attachment that is on the platform structure;

a first actuator connected at a first end portion to the platform and at a second end portion connected to the supplemental, marine drive system, wherein said first actuator is positioned to lift and lower the propeller shaft;

a second actuator having a first end portion connected to the platform and a second end portion connected to the supplemental drive system, wherein said second actuator is positioned to steer said propeller shaft between port and starboard positions.

22. The vehicle of claim 21 wherein the propeller is movable between a lower position below said horizontally extending panel and an upper position above said horizontally extending panel.

23. The vehicle of claim 21 wherein the first actuator is a hydraulic cylinder.

24. The vehicle of claim 21 wherein the second actuator is a hydraulic cylinder.

25. The vehicle of claim 21 further comprising controls on the platform that enable a user to remotely lift, lower or steer the propeller shaft.