Depth Sounder

[Paul Woo]

I bought "SYMPLISTIC" Hull #165 in May, 2001 and had the bottom painted while she was hauled for survey.  The depth sounder, a Datamarine 100, has been giving me erratic readings such as MSD (what does it mean), 2.50, etc. when the boat was clearly in much deeper water.  I have played with the gain adjustment to no avail.  The 4 ft and 8 ft warnings don't come on because I have run aground in Pamlico Sound, NC, several times.
 
 I suspect the problem may be the bottom paint that got on the through-hull transducer, which I'll check the next time I am on the boat.  If anyone who has this type of Datamarine depth sounder can give me your comments on your experience and observations, I'd appreciate it.  Is this a reliable instrument?  
 
 I would hate to replace a depth sounder if it's just been painted over.  By the way, to remove the paint on the transducer, if it's been painted, shall I use paint stripper?