Just installed a new thru hull transducer. 20 degree tilt. Very difficult to fit right between stringer and hull pocket on a 1999 islander. Less is more with sealant. I had to cut the spacer to get the threads exposed per instructions. Hopefully water will be clean and clear at this location. I reused a hole from a prior smaller transducer. See wood plug I used to guide the arbor. I enlarged the hole. It’s a tough job and there is very little room for error.