I've thought about making a DIY generator with a permanent magnet alternator mounted on a gimbal connected with a short piece of rope or cable to an outboard prop with a capped PVC pipe float. Tow generators get used in yachting, but cost too much (see Tow Generator
). You can make a DIY permanent magnet alternator by replacing the rotor in an auto alternator with a purchased rare-earth magnet rotor (see: Permanent Magnet Alternators
). Another solution is a smaller DC generator like a treadmill motor. You also need a cone to send down the line to kill the prop rotation so you can pull it in. It seems like such a unit would fit just fine in rocket box or a couple of 50cal boxes.
Having the electrical stuff out of the water makes it all much simpler. It would be cool if this could make enough power to run a 12v cooler/icemaker. I'd also like to use one of these to charge the battery of a electric water filter I made. Solar is great too, but this would be the night-time solution. You'd have to make sure that it wasn't an entrapment / Cuisinart risk though. Maybe just trail a buoy with a bright flag.
Has anybody already tried this?