Consider, if you will, the humble motorboat propeller. It is small - usually 3 to 20 pounds with a 9 1/2- to 16-inch diameter - and has a simple job. Its task is to keep its head underwater and turn, ...

This video follows the process of building a custom boat designed to test and compare propeller efficiency under real-world ...

From big boats to small, most have one thing in common - propellers. Boats move through the water with a gasoline or diesel engine that turns a propeller under the water. With the exception of ...