Ok, I'll chime in since I am a C-30 guy that removed the flapper. I cruise on the Chesapeake Bay and rarely see the conditions Neil describes. As noted in previous posts, the problem child is the "hinge pin", but it is replaceable, and if the pin fails the flapper won't exit the housing because the ID of the pipe nipples is smaller than the flapper, so all the parts stay intact, but as I found, not necessarily in their designated locations.
I am currently running a Centek 90° fiberglass elbow where the flapper was just under the winch in the port locker, and I've had no issues, but please keep in mind all the cautions above..replacing the flapper hinge pin is an easy job compared to most.
