Guy: sorry, I should have said machine screws. The idea is that the correct installation
for the Spartans involves drilling two holes through the hull, countersinking at both ends, inserting the machine screws do that the heads are on the exterior hull, those go through the seacock backing plate, and are secured with nuts. Then you fill in and over the exerior and repaint the antifouling in those spots. Hope that helps.
Shrew: I hear ya. All my seacocks are installed like that, and they have been in place since 1977 with no issues. All the sources I can find say that that is an installation
that was done for cost saving, and is not safe or correct. Believe me, I would much rather just stick the thing on and move on with life.
If anyone else shares Shrew's opinion that the machine screws are overkill and adhesive + screwing onto the throughull is safe and sufficient, please let me know. It would certainly make things easier.
pcmm: I think I have memorized the Compass Marine
site at this point, but I was looking for just that part of it and couldnj't find it, so thank you so much!
The issue with installing an additional backing plate is that I am not replacing the throughull at the same time (mine is fine, they are expensive, that is even more work and yard time than replacing the seacock), and the throughull is already cut to length. So if I drop a backing plate on there then 1) itis goingon area of the hull that is already built up, and 2) there won't be enough threads available to tie the throughull and the seacock together. If I wanted to do that, I would have to chisel out the existing fiberglass
to make room, then fiberglass
in a backing plate. Seems kind of redundant. That's why I am going with the "screw on, adhesive, bolts from the exterior" method.
If anyone has any suggestions or agrees with pcmm that I should also replace the throughull, I am interested to hear it.