The 937c unit is pretty old as we have not made them since about 2006 or 2007. It is a standard 2D unit and came in two versions: the 937c (200kHz single beam version) and the 937c DF (50/200Khz Dual Beam version). You can switch between which version you have by purchasing the other transducer and changing the Transducer Select menu setting. I don’t think that we support any new software updates for this unit anymore as the last was version 4.750 which was released back in December of 2009. It can work for what you have described but there are better options out there.