@jviss - dude - with all due respect - get off your high horse! Oh my, you're an electrical engineer and you've made a study of energy conservation. Have you made a study of turbines running off sailboats? Because if you have, please provide the data.That statement by Watt & Sea is nonsense. I am not kidding, I'm an electrical engineer, and I've made a study of energy conversion. Any bit of energy generated by the hydro charger is taking speed off your boat. Otherwise, it would be magic. Where do you think the energy is coming from?
Note that the Watts & Sea unit is articulated, you can pull it out of the water totally. So when racing and speed is of the utmost importance, you can pull it totally out of the water especially under conditions here the drag will have a measurable effect on your speed. You can then drop it down and generate electricity when the sailing conditions are such that it won't have a measurable affect on your hull speed. See @DArcy 's post above...
No one is suggesting that conservation of energy is not being maintained. That's a fundamental law of physics, we all agree. However, this is a very complex system with many variables at play.
dj