Before I cut the hole in my new 3/4 ext.ply bath sub-floor I want to ascertain exactly how large the hole should be and whether the flange that connects to the blackwater tank sits on top of the subfloor, or is recessed into the plywood subfloor:
-if it sits on top (maybe captured by the closet flange?) then that means this black flange will have to be unscrewed out of the tank, correct? if so, ugh. it's stuck. If you were able to get yours out, tell me how before I do some damage. If I had a clear photo of exactly where it was originally I'd use it for reference but here's what the mess looked like when I inherited it:
gratefully, rick O.