depth sounder
I have an '82 hunter 25, which draws 4'. Originally I used a digital depth sounder, which worked adequately, but when it got water damage, i replaced it with a garmin fishfinder 90 from west marine. i mounted it on my cabin bulkhead, it has alarm, and a digital readout, but what is nice is that it displays the area under the boat with contour and displays the bottom makeup which is great for anchoring. for $99, it is a great tool in a 5"X5" package.