Sorry I don’t know more about the total density of the closed cell foam. All I know is it doesn’t absorb water.Thank you Kpnkd! I also read that folks on this forum used a heavy dose of silicone to set the transducer against the hull...first putting the transducer in a bag of water as a test to make sure the location was acceptable. Just curious about this closed cell polyurethane foam.
Loren: Do you remember what solid sealant you used? Thanks!Remember that when sealing the transducer against the inside of the hull you must avoid any (tiny) air bubbles in the bonding medium. If using epoxy resin, even a stirred-in bubble will reduce the passage of sound signal. So, if you use a "foam" product that always has air entrapped in it, it will likely halt sound waves or severely reduce them.
I have successfully bedded an inside transducer with solid sealant, and the head of the transducer was also tight against the hull surface.