Powerboats have gone back and forth on many different forms of swing check valves in rubber and metal
They always wear out with no real way to tell and they have found a correct install with things at the correct height above the waterline solves most issues
12-14-2010 10:44 AM
A little info I found on this. It should be removed but the exhaust exit through hull needs to have a flap to keep out following seas.
12-12-2010 12:17 PM
The use of the check valve there is a nifty idea and theoretically should minimize the risk of a flooded exhaust (from cranking too long without firing, eg) getting into the engine.. but I suspect, as Denise suggested, that it became a trouble spot more often than it prevented a problem.
I'd venture to say that most systems will not have one in place and as long as you follow good practice you could eliminate it now.
12-12-2010 11:57 AM
My guess is the swing check valve would stick closed (or open) in very short order. C-30s the engine (I think) in the lowest part of the boat and the only right way to get really good access is to remove the galley cabinets. Sounds difficult but the guys that have C30s in my YC do it quite often when working on theirs.