I have no idea about what you are talking about..
 Thu this may help.
We would get a noisy lifter or bearing  or sound in an engine.. old school small block chevies..
I have a mechanics stethoscope, basically the old long screw driver to the ear trick, on steroids.

One could follow a vibration or transmitted sound very easy .. even tru side of the block and tappet covers right to the tappet bearing, dizzy bush, oil pump whatever.

 Been handy for other stuff like setting agax valves, finding air and water leaks etc

Thanks ‘Foxtrot Oscar’.

Sorry, I should have been more specific but yes you have hit the nail on the head with what I was talking about and agree with your comments.

To put it in to perspective I can hear it but others can’t unless I point it out.

I will follow through with the pro’s, just curious to hear comments.

I did actually have the engineer I use come out and listen before Christmas and he was reasonably happy it’s nothing to worry about and suggested we will look further when it is next out but I’m not so convinced. When you get very tuned to your own boat you have to go with your gut feeling. Particularly as it’s a new sound, hence agree with your comments about the potential of making matters worse.

I will get a second opinion and probably get a haul out as soon as I can. Not a cheap exercise but worth it for piece of mind.

Yes, always have my coastguard membership up to date but (Touch Wood) never used them apart from trip reports and would like to keep it that way.

Also having the gear box looked at in January in case it’s travelling down the shaft from there although I’m convinced it’s the prop / strut area although do know how sound can resonate to different places.

It is a little more noticeable in forward than reverse which is possibly one thing to point it to the gears. It’s starts getting complex because of course when both throttles are forward, one gear box is in reverse and one is in forward because of the clockwise / counter clockwise props so they can sound subtly different anyway

All a bit annoying considering I am particular about hauling out each year and doing all preventative maintenance before summer.