I have a problem with my huminbird fish finder, maybe someone could suggest
a solution for me.

It's a wide portrait with a tri-beam transducer attached on the transom. The
transducer is detected by the fish finder, and I have reset the unit to the
factory defaults and tried different settings to try & get it to work
properly. The water temperature gauge works correctly.

If I am in what I know to be about 15ft of water... the depth that is
displayed numerically is like... 549ft or so... give or take a few 10ft. If
I set the depth range to 30ft..... the terrain that is graphed on the screen
is what I believe to be correct... meaning that the bottom shows to be in
the middle of the screen.... 15ft. This works at other depths that I have
tried. The speed also shows 0.0 always as well.

Hopefully this was explained correctly.... maybe someone has a suggestion I
could try. I'd sure appreciate it!