Re: hull mounting a transducer, aluminum hull?
Screw it in with sheet metal screws. Put some sealer on the screws. The transom sheet should be .100". However, if you locate it in the area of a transom reinforcing beam, you will need to pre drill a hole as the beam is more like .187 and together you have a goodly amount of metal to penetrate.
I just glued mine inside slightly forward of the transom and slightly off center of the main knee brace. Works fine and even with a temp sensor it is about 2 degrees within the one on my trolling motor.
Mark
