Depth transducer mounting on cored hull

Is there a way to non-destructively find an area of solid hull in a cored hull boat thats in the water?
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Or where would you expect the hull to be solid?* I assume either side of the keel but how far out for structural integrity.
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Situation is were installing a new nav system & need to permanently attach a transducer to a solid part of the hull.*
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Thx, Philip

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Hope your enjoying your new boat!

(1) Find some thick waterbase jell. Goop up the transducer. Probe around to see if you can find an area that is solid and allows the transducer to work. Also bear in mind that many fiberglass layup even when solid have voids in them greatly reducing your transducers efficiency.

(2) Mount the transducer externaly on the transom.

(3) Or do it right and haul the boat. Find a good area for the transducer away from machinery. Drill the hole and remove a few inches of the coring and fill with thickened epoxy. Redrill and mount your transducer. Insure it's pointing straight down.

I vote for number three.

Dave N

Many boats have pads that the manufacturer put in specifically for mounting transducers, seacocks etc...

You*can identify these easily from inside the hull, just look for a square raised spot.

Wingspar and Ksanders have both given good advice. *Like Dave N, I vote for his number 3. *You can mount the transducer in the best place, and it is really not that hard to do. *You probably know this, but you can get a transducer that will compensate for up to about a 20 degree bottom angle. *This eliminates the need for cutting the block to make the transducer vertical. *That was a PIA. *Just drill the hole. *Gouge out about a circle of coring of two or three inches. *Pack it solid with thick epoxy. *Let it set up over night. *Redrill the hole and you are good to go.

Philip:* Door #3:** We have done this many times.* Hobo and our last boat had and have cored hulls and we have replaced*and installed transducers and thru-hulls.

On Hobo, where the coring stops, in relation to the keel prevents any mounting of a transducer.

Just think, how many people get to drill a 1-2" hole through the bottom of their boat below the water line (on the hard).*

I'm pretty sure the last time I did a cored hull, the transducer instructions suggested epoxying a piece of PVC in the hole to prevent crushing when tightening the transducer....it also helps with sealing up the core.*

I did it and it worked well.