1) No matter what manufacturers say, there are some boats on which it is
seemingly impossible to find a location where the transducer will be happy
at high speeds. The question really is how many holes do you want to drill
in your boat for the sake of experiment? On mine, I used some existing holes
to attach a piece of scrap wood. I drilled a million holes in that while
experimenting with location, and then used it as a template for the final
holes. Even so, above a certain speed I get an accurate depth reading, but
the thing doesn't see fish.

2) Inside mounting: You need a totally different transducer for that, and if
Zercom is like Garmin (the brand I bought), an inside transducer will only
work in a fiberglass boat.

Back to #1: Find someplace on your transom to attach some wood temporarily,
and build some sort of jig that allows you to move the transducer around.
Don't forget that distance from the prop(s) isn't the only factor. The depth
of the transducer matters, too.


"alex" wrote in message
...

For some years now I have a Zercom 165 fishfinder. At the time I
bought this particular unit because it was supposed to have a good
performance at high speeds. With the unit came a transom mount
transducer. So far I had poor results with it. It performs very wel at
low speeds but as soon as a come on a plane the reading gets flaky and
at a a speed of 25 knots or more I get no readout at all. I already
tried relocating the transducer, trying to find a spot with less
turbulence, but with little or no improvement.

Now I'm considering moving it to the inside of the boat. I suppose I
could mount it in the bildge, fixing it with some epoxy or sillicone.
Is there anyone out there who had similar experience or who could give
me some pointers in order to solve this problem ?

Many thanks in advance

Alex