I have 4 of those Datamarine instruments on our boat, of which 3 still work
(after making some repairs).

Datamarine instruments or a close copy are still sold by DMI
(http://www.dmimarine.com/) but they are very expensive for old technology.
But, your instruments may be able to be repaired and there may be nothing
wrong with the transducers. I think they will quote you for repairs before
starting.

If I were to change my instruments, I think I would make a cover that would
hide the existing holes and then buy some newer instruments. Navman have
reasonably priced units and then there are Raymarine and others. Not sure
about thruhull size, but you can always have the openings either glassed
closed and drill new ones, or if lucky, maybe the old holes can be re-used.

There is a company called Moor Instruments
(http://www.moorelectronics.com/). They make instruments that will fit in
the openings. Another is SR Mariner
(http://www.srinstruments.com/Mariner/default.asp) - they have been around
for a long time and instruments are inexpensive and work OK.

Good Luck!

"Chi Chi" wrote in message
...
Hi I just purchased a 1981 hunter 37 cutter and it has datamarine depth
finder gauge, wind speed, and a speed log gauge all installed in the
cockpit
on the wall on the port side of the companionway. None of these gauges
work
and are as old as the boat.
My question is what can I purchase to replace the depth finder in
particular
that will bolt up to the existing holes so I don't have to cut or patch
anything? Also what sort of thru the hull transducer should I buy to
replace
the old one? Any advice on this matter would be appreciated I'm a newbie
to
sailboats and trying to learn as I go. If You would prefer to respond back
to me directly e-mail me at
Thanks
Ken