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Notes and ideas for pedal powered boats from this site and around the web.

Pedal powered azimuth drives and or kort nozzle; contra rotating propellers. Hull to be narrow beam (ratio of 6 to 1 : to 10 to 1 length to beam ratio) Probably displacement type; possibly semi-submersible.
Possibly use two azimuth drives with applied braking on a differential to give independent drive power control.
./Car Differential with Balls-IkpTGkMxgLc.webm
./Car Differential with Belt 1--dtBWDVshYY.webm
./Car Differential with Bevel Gears 1-YjhzkV5Ya2k.webm
./Car differential with locker-xTYGVGU_g88.webm
./Face gear 6 - Drive for coaxial propellers 12-xda1WgL9fd0001.webm
./Drive for coaxial propellers 1-4mWe9EnW9hE001.webm
./Drive for coaxial propellers 9-t5u-_HslCxg001.webm

Javaprop For designing propellers


Ducted Propeller

Below image, we are focused on the nozzle on the left side, for increased thrust.

Comparison of Drag Coefficient Between Kort and Rice Nozzles

Figure 3 Transverse View of Rice Nozzle.

Due to the design (Figure 3), the propeller’s working area in the centre of nozzle, is approximately 40% smaller than the area of the nozzle entrance. This results in an increase of water speed and a decrease of internal pressure in relation with external pressure - which remains more or less constant.

Because of this pressure difference, a force P (Figure 4) is created on the external surface of the nozzle that is always perpendicular to this surface.
Due to the design of the outside trailing end part of the nozzle, the horizontal component of this force P creates an additional forward thrust on the nozzle; increasing the total thrust of the vessel.

Figure 4 Pressure Differences Creates Additional Forward Thrust.

Up to 40% of the total thrust is generated by the nozzle itself and is transmitted directly to the hull.

Add length to tip of prop blade where nozzle is wider to reduce clearance distance, shown in blue.

Kaplan Prop, for use in kort nozzles

Contra-rotating Propellers:
For straight drive
./Face gear 6 - Drive for coaxial propellers 12-xda1WgL9fd0.webm
./Drive for coaxial propellers 9-t5u-_HslCxg.webm

Rear prop should have more blades than front prop,ie four blades and five blades; however both props should provide equal thrust.

For Azimuth or outboard type
./Drive for coaxial propellers 1-4mWe9EnW9hE.webm

Constant-velocity (CV) joints
Tripod joint
./Tripod joint animation in solidworks--RMxVcq-RhQ.mp4

Power transmission, and direction. Spiral gearing shows better efficiency
Bevel Gears

Boat designs
Paul Gartside River pedal cruiser
Paul Gartside river pedal cruiser write up


Drive train: Bicycle pedal, with long chain going under seat (like recumbent tadpole trikes), back up to an sprocket axle, between two azimuth drives (contra-rotating prop?) in kort knozzles.

Backlinks: Boats

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