Mine starts immediately I throttle up from standstill or if I throttle up while motoring. It also happens in either
forward or reverse from a standstill as demonstrated to the shipwright at the Quays. The boat was tied up alongside
their pontoon and I chucked it in forward and reverse a few times while he had his head in the lazarette. He couldn't
give me a difinitive diagnosis but said it was not mechanical. So what do I do now ?. I could waste boat dollars
running around in circles trying to fix it.

Hi Sam, so it's not singing now, possibly because of because of growth build up as has been suggested. Seem like it's a good opportunity to prove to yourself that the issue is with the prop and a resonance issue. Dive on it and clean it and see if the singing returns. If so, you know for certain where the problem lies. Then just wait until you're next on the hard and get your guy to do the filing adjustments.

Right...so I've just spoken to Glen and given him the latest and yes he said he still reckons its a singing prop but
hasn't heard of it going away when the prop's got dirty. He said to take it off whenever and it's a quick job for him
to square off the blades. So I'm thinking I'll wait until slip time, get Dave Pollock to slip the prop off underwater, take
it to Glen and then take it to the marina to Propspeed it and put it back on while the boats on the hard.

Gravy7 said..
So you'll be towing the boat to the marina - or sailing?

Yes. It looks like the marina workboat will have to drag me to the slip. But I should be able to drive it away. That's the plan.