I have a 19' Regal which has what they call a FasTrac hull. This hull has a
step that is roughly in the center separating the front and rear halves of
the boat. This is designed to funnel air under the hull and reduce drag
providing more power/fuel efficiency with less power. I have the same
problem with my depth finder at 10+ mph. I have tried filling my bilge with
water and putting it in there and it does seem to work off and on. I'm going
to take the chance and epoxy it in. Hopefully everything goes well and I get
a decent signal. I boat mostly in Tampa Bay and have found myself too
shallow on several outings.


"noah" wrote in message
...
On Wed, 17 Sep 2003 20:05:56 GMT, (alex) wrote:


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


Hi Alex.

As Doug pointed out, placement is critical for both "stern mounted"
and "through the hull" transducers. Any turbulence or "bubbles" in
the water flow around the transducer will cause problems. Usually, a
transom mount is placed near the first "hull step", away from the
prop. It should also be mounted roughly "even" with the hull
(depth-wise") to 1/2" below.

If you look up (google) fish-finders, you should find some good pages
( I did it not too long ago, but didn't keep the url's).

There are various ways to mount the transducer inside (through the
hull), but *don't* use silicone. It will kill the signal. Epoxy (for
fiberglass) and "water boxes" for aluminum, are preferred.

Good luck,
noah