>>> Home made wind turbine

This is a great article with lots of pointers to other sites giving some good details on building your own wind turbine. Its geared around power for a small camper or other "in the field" situation, but I bet many of the ideas could be adapted for on-board use.

And it’s going to be much cheaper than commercial solutions if you are handy and can whip one up from eBay and lumberyard parts.