Cal 9.2 SilverSwan
I've installed a ST30 in my Santana525 and a ST60 in the Cal 9.2. Both are epoxied to the inside of the hull and read to the max depth of the lake. While sailing on a Cal 2-30 in the SF Bay, it also had an older flasher style depth system with the puck glued to the inside of the hull. You can use water, grease, etc to couple the transducer to the inside of the hull to verify the sensitivity/ reliability of the system prior to committing to gluing it in place.