Wow, thank you, that was quick! My Alubat is aluminium and lift keel, my fuel tank is integral just fore of the keel so I can only locate the transducer in front of the tank where the hull rises up at 9 degrees. My other limitations is that she takes to the ground and I cannot sit down on the transducer. Welding a box is major (also within 4" of the tank!). The transducer reeds a standard 2" thru hull bore.