High Pitched Whining noise

I have always had good advice on hear so have another problem I have encountered which I hope someone will be able to help with.

The boat is a Sea Ray 395 Sport Cruiser running on a diesel Yanmar engines with twin shafts. Last year all was running nicely. No unusual noises. This year I replaced my older propellers with two new propellers as the old ones were pitted badly and probably were the originals from when the boat was new. The props were replaced like for like so no change in size or pitch.

Boat went back into the water and I can now hear a high pitched whining noise when running at about 8 knots. When I accelerate the noise seems to get higher in pitch which I can't seem to hear but my wife can and she says it's uncomfortable. It doesn't seem to go even at 18 knots cruising. When I slow down the noise reaches a pitch that I can then hear again.

When I steer to starboard and the boat turns the noise goes away completely. (have not tried to port to test the noise). When I put it back on a straight course the whining noise comes back.

Has anyone out there experienced anything like this please, any ideas what it could be and any solutions please. Thanks in advance for advice.

It's probably "prop sing" caused by the shape of the prop trailing edges. Talk to the place you bought the props.

Thanks hottoddie.

I have spoken with the prop manufacturers and that's exactly what they have suggested. My mechanic has been over the engines and listened everywhere and he also feels it could be prop song. It's only coming from the port side. Bit annoying but have been given suggestions on how this could be stopped so fingers crossed.

I find if I change my boat trip plans for the day without asking her if that is what she wants to do, the high pitched whining noise increases in intensity. Then there is a period of dead silence and that is when things can get really dangerous. So like everything with boating, it is all about prevention. So you need to get ahead of it and increase the communication in advance.

Sorry--- I may be talking about something else, now that I re-read your post.