Good luck
I bought a very expensive transducer for through the hull sounding and had no luck anywhere on the boat. the antifouling paint may have been the problem or the claim to go through 3/8" fiberglass was false. It now is on the back of the boat and the clutch is lubed well to slip. If you could run it through the retractable keel opening and mount it forward you might have a chance. I didn't want the wire to get caught when I had to retract it.