: My 430mm wide hull glassed on the outside a week ago is now 470mm wide. I
: hope to sand and glass the inside real soon before my design concept
: changes from narrow minimum rockered hull to a sea kayak, and before any
: cracks appear on the inside. Is this amount of movement normal, or is the
: wood I am using (New Zealand white pine) particularly susceptable to
: shrink/swell compared with cedar (cedar is very expensive to import here)?

Brad,

I beleive this has to do with changing humididty after you glassed the outside.
In your case I assume it became more humid after you glassed, and the wood swelled on the inside of the hull pushign the hull out.....

so with that theory, we can hope for a few dry days, and it should come back in. Maybe you can dry it out some how? Otherwise, you could set up such that the hull is forced together before putting the fiberg glass on, and hold it there while the FG sets. It will spring back after you release the hull, but not a lot. It should stay close enought to join the hull and deck, assuming it is some kind of covered boat.

I did infact have to spread my S&G hull back out about 3cm for the same reason. I then put FG tape on the seams it sprang aback about 1cm. If I'd glassed the entire interior of the hull I'm not sure if it would have held the shape better or not.

good luck,

Myrl