A bronze cap of the same material and schedule will be just as
reliable as the thru hull which is a no back up component. Filling
the space with something resilient and flexible will exclude water and
also serve as a plug. I'd much rather depend on this with the thru
hull and inner nut sandwiching the glass that grinding back the hull
structure and depending on secondary glass bonds.

I would just leave the seacocks as you suggest except that they are
gate valves that I'm replacing and relocating at the same time.

--

Roger Long



"chuck" wrote in message
oups.com...
Do yourself and the boat a major favor. Do a professional job and
glass
the hole. For safety sake if for no other reason. You won't have
electrolysis issues and potential leaks. If you plan to reuse it at
some time, just close it and take the handle off. Caping it might
not
be the right move.