Okay I know absolutely nothing about this but maybe someone here will have seen or heard about this...
The other day my wife was talking to someone about generating
power on boats. This guy apparently told her about some sort of a
generator that, while moored, hangs in the
water and works off of the
current of the tide and slowly charges your
batteries. I have heard of no such thing and cannot see how such a slow moving
current could possible create enough
power to charge a
battery, let alone an entire bank.
This might be an option for recharging
batteries while under sail though.