Re: That Darn PO!!
Folks, thanks for your many replies. The knowledge of sailnetters is truly fantastic. I see some great advice here, and a couple of real jewels for my particular situation.
I was not aware that spin welding was a common capability. Thanks for that. Having a local firm spin weld a new fitting on the tank is greatly preferable. A special shout-out goes to Bubblehead, who gave me a firm name in Annapolis! That's less than an hour's drive from the boat. That's what I will do over the winter when I have the boat hauled in Nov.
Other techniques you mention would be equally valid but don't really work for my configuration. I do not want to permanently attach the valve with, say 5200 or epoxy as I have almost no clearance and I'd then have to disassemble the settee and knock out a tabbed bulkhead, or else ruin the tank, to remove it. Trying Teflon tape is a good idea and I already did that -- I used plumber's tape to try sealing the valve. I cannot relocate the valve. It is attached the the lowest point of a roughly triangular tank side. I'd end up with water I could not remove except by manual pump through the tank access, and I would need to cut a new hole in a tabbed bulkhead to put it in.
T. P. Donnelly
S/V Tranquility Base
1984 Islander 30 Bahama