GARMIN GPSMAP Fishfinder
I know this is a sailing site, but when I started looking at depth instruments for my H-26, it sure seamed like you paid a premium for a little round (or square) sailboat depth finder. For the same price or less, I found I could pick up a fishfinder, with an integral GPS. I installed the transom mount transducer in the bilge with RTV to shoot through the hull. I set my finder to measure from the bottom of the keel, so I always have some safety margin. The GPS works great, has a Man overboard feature and NMEA outputs so it can control my autopilot. It also lets me check bottom contour and the type of bottom (within reason, and if I did cut a hole, it would also tell me water temperature for swimming. I mounted it on a quick release bracket next to the companionway and installed a second mount under the companionway. That way, when I lock up the boat, the GPS goes inside. As they say, think outside the box.