hi Greg.....I bought the boat used with the 550 in there, as for the ducer it looks like your basic transom ducer in which he put inside the hull(it works) , doesn't look like a puck tho .....I kind a like it in the hull. so thinking of up grading to color with DI and possibly GPS weather I need it or not. now if I where to take out the ducer and epoxy what is the easiest way to dismember that area (ducer and epoxy) so I can put in a new ducer in. thanks Glenn sorry ...both treads are almost alike.