Seam caulking question

[Woodlouse]

I would tentatively suggest that sika might expand/rebound better, to fill the re-opened gaps,when the planks shrink again, eg during a winter layup? Compared to trad caulking which might stay squashed?

However caulking is part of the structure of the hull because it stops lengthways movement (shear) between adjacent planks, thus protecting the fasteners from being wobbled in their holes, and contributing a lot to the strength of the hull.

It's a complicated subject..I would be interested to know what a top modern builder of trad gaff cutters, eg Luke Powell, has been using in his newbuilds since Eve of St Mawes.

Indeed sika does expand and contract with the planks whilst putty can squeeze out and stay out, alternatively gaps can form where there's shrinkage but that's easily fixed by just smearing a bit more putty in. Course, the best thing to do is keep the boat in an environment where the planks don't shrink and swell too much too often which basically means keeping her afloat as much as possible.

Not actually sure what Luke Powell used but if I had to put money on it I would say putty.

 

[Sundowner 39]

+1 sniper
we also used a little paint in the mix....you can paint the hull with pitch but you "Caulk and Pay the seams first"