The above concept drawing shows a small prototype drag-propulsion sail boat propelled by an existing 4’ diameter involute spiral wind turbine. In larger streamlined application, it should revolutionize sailboat design by creating very smooth and high efficiency transfer of wind energy to pushing the water between the split hull of the boat.
When the boat is anchored in a current, it can generate electricity. The same mechanism can be used to extract power from any shallow moving water when anchored in-stream. This could be used to charge batteries for alternative electric motor propulsion!
The multiple paddles are pulled through the water along tracks by cables which direct them around pulleys and up out of the water as they return to the front.
Numerous variations can optimize different functions and conditions, such as enclosed ducting and tilted paddles for planing in high winds.