otnmbrd wrote:

Doesn't really matter what size the boat is, you will get some degree of
"flex", especially when you remove it from the water and put it on a
hard stand. BG you want to see flex, you should watch and listen to a
large tanker at sea, or watch one go from hog to sag when loading.

Sure. Why else would they build expansion joints into the upper decks of big (or even
medium-sized) ships?

The only way to have zero flex would be to have literally infinite rigidity. The question is,
how much is too much, and how much is marginally greater rigidity worth the other sacrifices
made to increase it?

1/16" doesn't sound like a problem to me, although the latch sounds like a PITA. Another issue
is that fiberglass does lose a bit of torsional strength as it flexes many times... just like
any other material. The nice thing about fiberglass is that it has a very high number of load &
flex cycles to fatigue failure. Great engineering material, pity it's so heavy.

I remember reading about a New Orleans Marine hotshot racing boat built back in the 1980s, which
had a hull & deck of uncored glass & mat with a subimposed grid of straight S-glass. Everybody
guffawed and said "Those hicks sure don't know how to build racing boats, shoulda used foam
core" but the builder shrugged and said that they measured the bend in the hull/deck with
15,000# tension on the backstay.... it was 4 thousands of an inch....

Fresh Breezes- Doug King