Dear Rehd:

> what would cure this problem before it happens ???

I am certain that my deck and hull started out matching along the sheerline, having been built on the same form. However, when I needed to remove them from the forms for some reason, like glassing the inside of the hull, or making my coaming lip, I think each half was subjected to different forces, and changed shape in different ways. Specifically, I think the large hole I cut in the deck for my cockpit allowed the deck to relax some, accounting for the spread. I compounded the problem by installing a super strong coaming that strongly resisted being compressed.

The hull probably changed little, but my attempts to spread it were met with little success. So I compromised by stretching the hull as far as I could (after it was glassed and tough to change) and squeezing the deck (after it was glassed, had the coaming installed and tough to change) and then taping it in place, (LOTS of tape, LOTS of pressure) then fiberglassing it inside and out. It sure feels solid now.

I have read the previous replies to your question, and I like Ross' answer the best. It is simple, elegant, and effective. Check early and often and when apart, or off the forms, secure the halves in such a way that they are held at the proper dimension. Applying glass and epoxy by itself doesn't (shouldn't) change the shape of the wood, it's the absence of any support for the not-very-strong-by-itself edge glued strips that gives the opportunity to flex, sag, stretch, and then be locked in place by the fiberglass. The way to avoid it is to lock in the shape when it's in the shape/dimension you want.

I didn't have the experience of knowing how the wood could move so I didn't plan ahead. But I was able to recover just fine. The beauty of the strip building process is just that. A series of small steps, none so large or critical that a misstep is hard or expensive to correct. I really needed a process like that.

Ed Valley