Depth transducer/fish finder for inside the hull mounting

[phorvati]

I need a secondary depth finder and do not want to drill another thru-hull.

I have a balsa core sandwich structure on a C&C 38. Can anyone recommend make/model of depth or fish finder that is known to work from inside the hull.

I read some articles on how to mount it with various bedding materials etc. I tried using my old (datamarine sandpiper) depth finder that i know works, and had no luck using it inside the hull. This was my spare but i needed a thru-hull for another purpose.

[r.furborough]

To use an in hull transducer with a cored hull you have to remove the inner hull and remove the coring material so the transducer is in contact with the outer 'skin' of the hull. Only way to do it.


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[Lepke]

You could mount it on the stern.

[onestepcsy37]

Balsa core may not go all the way down to the bilge area. On many boats its only used higher up on the side of the hull. I have no knowledge of C&C construction but maybe an owners group?

[phorvati]

Thanks,
I can see where sandwich structure is tapered. namely 12" squares around each through-hull. Besides this, balsa goes all the way to the center line. The original transducer was mounted in a through-hull installed post factory and in a place near the center line forward of the engine, aft of the keel. When i took it out, I noticed it was not bedded with epoxy so there was just balsa (luckily dry) all around. i ended up filling with thickened epoxy mix, and re-drilling before re-purposing it.

So is it worth a shot for me to try the same old datamarine transducer at a tapered section? Maybe there is a second life for this unit after all?

[smac999]

get a p79 inhull

[phorvati]

I see that p79 is a garmin in-hull transducer. I have GPSmap 172. Some online shops list GPSmap 172 as a compatible product to p79. Does anyone know if p79 can interface with Garmin GPS map 172. In owners manual for GPSmap 172 it states that it needs GSD 20 portable sounder module which is a bit too expensive. perhaps p79 came after that owners manual was written.