First a bit of history. On my N46, my transducer would display random numbers in shallow water and or tied to the dock. I replaced the transducer, problem gone.
Now, my 2008 AT's Airmar transducer started displaying random numbers in shallow water and or tied to the dock. I do have a secondary, independent, glued-in depth sounder that seems to be accurate.
I had the diver clean the Airmar's face every time he did the hull, no change in reliability. This haul out, I checked the face of the transducer, clean as a whistle.
I had the Airmar transducer replaced. When I get back to the boat, I hope to discover, problem gone.
What I would really like is, a depth sounder forward of the engine room, for poking around in the shallows, knowing at other than minimum speed it would be not be accurate.
The meek will inherit the earth but, the brave will inherit the seas.