Kent, we have also the noise from the greywater sink in the foreward head, but only when motoring at a certain RPM. When we got the boat I was looking for a pump that „runs dry“ but could of course not find one…, then we found out that it is just a special frequency that starts the noise, small amount of water stops it immediately...
The P79 sound is not very loud, at the beginning I could hardly hear it. But is is like this drop of water that falls on the head every minute – when you start to hear it you are waiting for the next tick and that drives me crazy J
It gets louder when in deep water (frequency change) and more silent in shallow waters. There is absolutely no sound from the two echo sounders that I have in „Through hulls“, the B&G and the DST800 that I use.
Unfortunately there is no switch for turning the P79 on or off and it is stated in the documentation that it must not be disconnected/connected from the plotter when the plotter is powered on – so diconneting/connecting requires plotter Off/On. That is the reason why I disconnected it and have it only as a redundancy system (number 3 J ). But maybe I find a way to isolate it then I will leave it on and watch the fishfinder Screen until a fish pops up
KALI MERA, SN120, still on the hard in Trinidad but in the water again in two weeks