Coming to this thread belatedly. Over the winter my yard replaced the hot water heater, which was leaking. I think they must have moved hoses slightly in the process, because when I tried to reinsert the frame yesterday I found I could not get it back in, despite a cutout in back. I've never had this problem previously. In the end I decided to replace the black hose with a longer one. This causes the hose to arch more than before (still sloping downward, however) so that it has more clearance to the back of the frame.
FYI, the reason I had removed the frame is because we found water in the drawers and traced the problem to cracks in the plastic elbow assembly under the starboard sink drain. It took me quite a while to figure out what that part is. For future reference it is a Forespar drain assembly SW-2 (part number 907014). That's for just the elbow tailpiece that cracked. (The full drain assembly is SW-4.) Miraculously the marina store had one in stock!
T. Scott Thompson
Catalina 320 “Surprise,” #653 (1999)
surp...@thompson87.com