Malcolm,

At the risk of wearing out my welcome, there is one point that I forgot to
mention. That being, the deckridge. I tie the deck tubes, both fore
and aft, into the coaming and stem/stern plates as securely as possible to
create , in effect, a continuous rigid deckridge. On the Sea Rider, the
small rigid coaming is bolted through the deck tubes fore and aft as well
as through cross sections 3 and 4 and helps keep the sheer from "re-flexing".

So, in reality, it a combination of factors that effect maintaining the rocker,
chines, and sheer. Also, the number of cross sections also effects hull flex /
rigidity.

Tom