They look more like a trolling motor. Unfortunately, they aren't much less expensive than the W&S. Still in the $5k range.

I love the concept of a hydrogenerator, but for $7k I could cover my boat in solar panels and have all the power I could dream of needing whether I'm moving or not. With the new shapes of panels available that are thin and you can walk on them, the options for where to put panels has increased dramatically.

Something is going to have to change in the economics before wind or hydro make any sense from a cost perspective.

This is one. There is another that looks more like a trolling motor.