Try something different
I installed a GARMIN GPS125 Fishfinder. It was cheaper than the dedicated sailboat instruments, and did not require any holes drilled into the hull. The fishfinder provides depth, bottom contour and bottom type (soft or hard) to assist with anchoring. The GPS functions to provide all the typical GPS things, including speed, which corrects for current, set and drift, etc. It also has an NMEA output for my autopilot. If you elect to drill a hole for a through hull transducer, it will provide water temperature too. The last benefit is that my kids are entertained looking for fish. If I ever decide to take up fishing it would be pretty handy. I installed it with a long lead and two Goldeye quick disconnect mounts available at most department stores. One mount is in the cockpit, close to the companionway hatch, the other is behind the step in the aft berth. When we are sailing, it is mounted in the cockpit and easy to see and use, and when we are done it unsnaps and gets mounted below deck where it won't be stolen or damaged by weather. It can also be used for navigation below deck. The power consumption is very low also, less than .25 amps. This has worked very well for us.Mike PajewskiH26 "Loon"