It was mounted on the forward bulkhead in the saloon. As a kid I would call out the depth to my dad at the helm. We also had a RDF with crystals for local radio stations. Not quite as fast as the stuff we have now. We went from RDF to Loran-C and TD charts. For some reason the Lat/Long translation on the Texas Instruments unit was just not reliable over any distance. I never really trusted the Loran-C so DR was important as a double check.