I would like to mount my Humminbird HR610 depth finder transducer thru-hull in my 2003 1800SR MAXUM I/O boat. I currently have the transducer sitting on the hull in front of the bilge pump under the engine. It is in my garage and not in the water currently. When I turn on the unit, it reads at 3.1', but constantly blinks - according to the user's manual it should not blink, but should be a constant read-out. I am thinking the blinking is because I am not getting a good signal read thru the hull. I want to make sure of the location before I expoxy it in because once it's there, well, it's there! Any suggestions would be appreciated, especially from someone with a similar boat/situation?