Once again Im heading towards that painful $3000 anti fouling exercise and thinking again about whether ultrasonic transducers really work to stop growth on a hull. Supposedly it does but finding proof is really hard.

Perhaps this is a way to find out:- Yesterday went for a nice sail up and down Pittwater. This morning I realised I left the power on on the boat by mistake (for the beer fridge), but including the fish finder/depth gauge. It occurred to me to not turn it off but to wire it so its alway on and after a month or three when the boat gets slipped have a look under the hull near the fish finder and see if theres less growth?

What do Seabreeze gentlemen (and others!) think? Everyone leave their fishfinders on all the time (wire them direct to batteries) and in a few months we should have a result? Let me know if you want to join in.