Re: Gasket rot?
Never seen the gasket itself rot.
I have seen LOTS of boats leaking where the boat transom itself has rotted away and got soft behind the gasket.
I have seen LOTS of boats leaking where electrolysis has eaten away the aluminum of the transom shield itself (but the gasket is still there).
I have seen LOTS of boats leaking where the 2 bottom bolts have been eaten away by electrolysis, letting the transom shield loosen from the transom (and eventually leading to transom rot).
But I can't say I've ever seen a case where the gasket itself has rotted.