I am attempting to remove my Raymarine ST40 Depth Transducer to replace it with a ST60 unit. Apparently when Hunter Marine installed the transducer in the factory they decided that no one would ever want to remove the unit. The unit is caulked in with sealer that is a bear to remove. I have gotten down to where the caulk is even with the inner hull. Any suggestions on how to get down between the hull and the transducer to remove the caulk so I can drop the unit out of the bottom of the Model 260? I have thought about drilling into the caulk from the top to attempt to release the unit.