Wave power.

[FredFarnesworth]

I have a fair-sized boat. Any ideas/suggestions about wave power (while anchoring) to charge 12V battery banks? Any URLs for similar projects?

Thanks, - Fred

[Dan M]

This may not be what you're looking for, but when I'm anchored, and the waves are substantial there's usually wind, and if you're anchored right, your orientation to the wind doesn't change much.  It seems you could use a simple wind genny.  You might not even need a yaw bearing as long as the boat keeps facing the same direction relative to the wind.

The other thing that comes to mind (and this is a serious reach) is to use "roll stabilizers" on each side of the boat and instead of having them anchored to the boat, run the line to something like a recoil starter that has a spring return.  You have A LOT of force (or torque) and very little velocity, so you would have to gear it up between the "recoil starter" and the generator.  It seems a pm motor with a 50:1 gear box on it might be appropriate (don't use a worm gear drive, you can't back through it).

-Dan M

[Dan M]

Now you've got me thinking about what it might look like:

Maybe something like this.

-Dan M

[DBGenerator]

Here is something I found.

http://www.aquaenergygroup.com/home.htm

[Ungrounded Lightning Rod]

You might want to think about using a hydraulic transmission, both to raise speed and convert linear motion to rotary.

Hydraulic cylinders on the arms, valves to serve as a "rectifier", and a hydraullic pump/motor on the genny.  Maybe an accumulator to keep it spinning continuously (though start-and-stop might produce more average charging current.)

[thunderhead]

I've been scratching my head and thinking about tidal power, especially as we are considering a property on a tidal island in western Europe, where the tidal reach is the second highest in the world.

Designs based on a Sandia-Savonius rotor immersed in water and with the generator at the top of the shaft seem to have been successful for the SeaPower EXIM project.  A Savonius tidal design would need a modified version of the "brake disc" generator, possibly with more magnets to get decent voltages and frequencies at the 50-100RPM that is going to be produced.

There was some discussion here about tidal power back in May.  I guess the big problem is the environment, in particular fouling and corrosion.  GRP might be a material to consider, or maybe stainless steel.  At least the generator can be out of the water, though, since the Savonius is a VAWT design.

[mcgivor]

wave power is nice, if you were able to build on in the ocean it would be great.  Popular Science had an article on wave power a few years ago.  Also can you anchor it to the bottom, and use a float?