The renowned Trevethick proposed the Archimedian screw for boats in 1815 ... with section screw blades of an increasing pitch, and not the Ericsson propeller. Various patents were taken out ...

Heartbeat EKG design with propeller for powerboat lovers, yacht owners, sailors, weekend captains and all who love their boat and spend every free minute or vacation on it. Also suitable as a ...

It took a few tries to get the size and pitch of both propellers narrowed down to where the boat would move forward into the wind, but move it does. A second major iteration of the build uses a ...

Most famous of these is probably the toroidal propeller that made waves a while ago, mostly in the field of flying drones, but commercial toroidal boat props exist too. Test results of the ...