I am thinking about purchasing either a Humminbird 215 or 220 for mounting in my Heritage Redfish 12' SOT. A lot of kayakers have equiped their yaks for electronics; in fact, the Redfish has a "console" for mounting a fishfinder! I would epoxy the transducer in the bottom of the hull for a through-hull application. I have to since I sit my kayak on stumps at times fishing structure. Humminbird claims that the temperature sensor would not work this way, but I'm not sure why. It might not be as accurate, but the reading would be within a fixed offset, I would think. Any ideas out there? Thanks!