Hull Stringer Sealing?

[kb79]

I'm replacing the head Y valve on our boat, and the old valve was mounted to the hull stringer using four coarse thread screws (look like #10 screws to me). The new Y valve has a slightly different screw pattern, so I'm only going to be able to reuse one or two of the old screw placements.

That leaves at least two open holes into the hull stringer. I'm not quite sure what the stringer material is, but it seems likely to me that if those holes aren't sealed, they could allow moisture into the stringer - seems like they should be sealed.

Am I right? Can I leave those holes open, or should I seal them? Assuming they should be sealed, what should I use?

Thanks for the help. You guys are always awesome.

[Vasco]

Nice boat. I think the stringers in CS boats were solid glass. I would just fill the screw holes with epoxy.

[sailvayu]

Shoot a little caulk in each hole first even the ones you are putting screws into. A polyurethane is best but silicone will work. I like to use a caulk called PL ultimate I get from Lowe's Hardware for that type of thing. About a 1/4 the coast of the "marine" caulk and I have had good luck with it.

Fair winds

Wayne Canning, AMS
projectboatzen.com

[barnakiel]

Sealed and avoid holing. Not only an issue of water ingress but also of construction strength - for the same reason we avoid making too many holes in mast extrusions.

b.

[kb79]

Actually, that's a good point, barnakiel - I hadn't really considered not drilling new mounting holes, but maybe it makes more sense to bond the new valve?

[barnakiel]

Invent. Perhaps a pad can be glued in place and the valve can be attached to the pad?

b.

[harryrezz]

Just my two cents worth - If the stringers are glass I wouldn't be too worried about weakening them with a couple of little screw holes, but the idea of affixing a mounting pad to which the valve can be attached is a good one. You could build one up out of glass mat and resin and tab it into place (using a bit of the resin to fill the old holes first) or just use a hardwood block which you could also epoxy into place and encapsulate with glass to protect it.
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