I have a 410 Sundancer and would like to replace the Ray Marine Fish Finder which is original equipment. There are much better Fish Finders out there today (at least with better screens). I am guessing the OEM sonar transducer is installed in the round cut out in the bilge. There is a round "plug" with a key dangling on it and this plug appears to be screwed into these round cut outs. A cable is attached to the "plug" which I believe is the transducer cable. Has anyone done this before and have any insight on how to do this? I hate to open the plug and water start gushing in.
