Nope, the accessory trolling motor transducer is on my second boat, I move the head unit to the boat I am using and don't have a switch. My question was about using it with a transom mount only ducer on my saltwater boat (21 Seaswirl Striper WA cuddy).
I called the HB help line and got the answer. Under advanced mode there is a setting for water type. What I needed was "deep saltwater" setting. Was out just yesterday in Puget Sound to test it out and got good readings down to 750 ft which was as deep as it gets near where I was fishing. Since I was fishing for silver salmon which are usually shallow, but out in open water, I set the max display depth to 160 ft to see more detail in the display in the depth that I was fishing. It continued to display the actual depth in the digital readout. This worked great but unfortunately silver fishing has been slow so far this year. We found numerous bait balls but landed no silvers.
Thanks for your reply.