I read years ago that one could mount a transducer on the inside of the hull in a bath of oil. I tossed the idea around for several years whether to drill yet another hole in the hull or somehow attached something that would hold oil on the inside of the hull. ... After a lengthy consultation with the transducer manufacturer, he told me that yes, on can mount the transducer on the inside of the hull, but in a seawater bath. He also reminded me that the main ingredient in polyester resin contains styrene, also, one of the ingredients in ABS. So, there's my answer. Cut a length of 3" ABS plastic pipe on an angle to match the hull and set it in place with thickened polyester resin with milled glass.
