On more than one occasion, the Brunton 70P deck mount compass has been a lifesaver in heavy fog off the coast of Maine. I have it mounted on my expedition kayak and have started out in perfect weather only later to have been overtaken by heavy fog. With basic navigation skills (inbound course = reciprocal in degrees of the outbound course). Taking into consideration wind and tide, I have arrived at the exact mark needed to guide a course safely home. A simple recommendation: when mounting, skip the mounting template that comes with the compass. Remove the screws from the compass frame and insert the compass in the molded deck fitting. Carefully seat the compass and check around the edges for a watertight fit. Then drill. Safe paddling!