5 ms·
It's also possible to use a propeller sail to go directly upwind in water. You don't need gearing in water if you pick the right pitch on your underwater prope
by LeifCarrotson 8y ago
It's also possible to use a propeller sail to go directly upwind in water. You don't need gearing in water if you pick the right pitch on your underwater propeller relative to the pitch of your sail/fan.
http://www.sailwings.net/windspinner.html http://www.sailwings.net/windspinner.html