exhaust flap
I changed out the exhaust flap on my 27 with one fromm catalina direct, you need two people to do the job, the old bronze fitting has a nut on the inside of hull so while you unscrew this someone needs to hold the outside with a pipe wrench to prevent it fom turning. the old exhaust fitting had a long stub with threads inside the hull requiring many turns to remove the nut , tiring to do within the space you have to crawl into but not that difficult just tiring.now i believe the the transom is plywood cored and after you remove the old fitting it should sealed with epoxy ,something i learned after i did my changeout. But check the wood it may be sealed already, or I could be wrong and the transom is not plywood cored and there would be no need to epoxy thus eliminating one more step. the new exhaust flap fits in the hole and attatches by 3 screws from the outside of the hull, which you will need to drill, and epoxy if you have a cored transom , then insert fitting with 5200 sealant and screw down. your exhaust hose needs to be removed to do the change out so at that point you can inspect it and detirmine whether it needs replacing or not, just replace it.
