I'm replacing the 4" exhaust hoses. After pulling them off, I see inside the thru-hull stubs (going into the ST), a couple little brackets riveted to the thru-hull. One side has a vertical bar and the other side was missing and one of the little brackets was only being held on by one rivet.
What are these (or were these)?
And do I need to them? Should what ever it is be replaced?

Thanks,
Kevin

They held flapper valves. Mine have been gone since I bought mine in 2000...no problems

Thanks for the reply. Guess I won't worry about them.