I 've no idea whether it works but my project for this winter was to make an ultrasonic anti fouling system. There are quite a few expensive commercial systems out there that promise much but with flimsy evidence. I bought a kit from Australia and have happily been soldering away. The cost of course was a tiny fraction of an 'off the shelf ' product. My guess is that it probably will have minimal effect but it 's been fun building it and I discovered loads about electronics on the way.

Finally completed it today and pressed the the button to hear a series of "whale-like" utterances. All very exciting seeing my first electronics project come to fruition. We will fit to the hull next week and will keep you updated as to what happens. It will certainly deter dogs but if it deters barnacles too that will be a bonus!

Simon

Unscientific I know but I 'd say my home made Ultrasound worked really rather well. After 11 months (the last 6 of which were spent sitting in a marina) she came out with just slime and no barnacles hanging off the prop. Really rather pleased!