Marinette Boat Forum

Guys I found a round, about 1 and a half inch diameter, thru hull that is constructed of bronze covered with a copper cap. It has DO NOT PAINT on it (it was painted) and a spot for a wire to connect on top (inside). What is it?

I'd like to tell you it's a Capac sensor for monitoring galvanic corrosion but your description doesn't match. Capac units (on the exterior/ hull side) have a plastic housing approx. 10" dia and stamped "Do Not Paint" with the sensor about 3" in dia in the center. The sensor is actually the part to be left paint-free, it doesn't matter whether the rest of the housing is coated. The sensor is made of a silver chloride material, not brass. If you can gently remove the paint with a thinner solution - no abrasion - a cloth rag is ok - you might see that it's not brass. On the inside, Capacs have a post to which the meter lead is attached.

If it is in reality a Capac my guess is that its condition indicates it's past its useful life judging from the way a PO treated it.

And as I think more about what you describe (bronze, 1 1/2" dia), it's more likely that it's the business end of a sonar unit. That's the size of the sonar (depth finder/fish finder) on my former M. I was, though, able to paint the sonar with a special water based paint (sold at West Marine and others) to keep the barnacles away.

Next time we get queries like this a picture is worth...a lot.

DITTO Transducer


dave

On the older Marinettes the capac is about the size you describe. Mine is about 1 1/2 with do not paint on it. Trace the wire see where it leads

Here is a picture

I believe that is a thru hull temp probe.

I am just now reinstalling exhausts, tanks, generator and am trying to zero in on wiring. This weekend I will chase down the one wire that was attached to the top. I want to say it has to be part of a Capac but maybe it is some kind of transducer.

The Cathode for the CAPAC is coated with Silver/Silver Chloride as a ref. Cathode. It is fragile and can be damaged easily by scratching etc. The pic. of the "Think" does not appear to be coated with it.


dave

Was the bottom sandblasted? That's exactly what my capac looks like

Yes sir it was sandblasted. In that case it should be connected to the galvanic isolator right?