My boat is a 2000 Maxum 2300sc which has a Standard horizon depth sounder (Model D40BD) with a through hull transducer drilled right through the hull most likely installed by the manufacturer. The unit is getting power and all functions seem to work normally except giving me depth indications. If I cruise at a speed over 40mph for several minutes it will start to indicate an incorrect depth which is usually around 300 ft. As I slow down to below 35mph the display stops indicating depth and just has three dashes. Does anyone have any idea what could be the problem.<br /><br />Thanks
