On Sat, 27 Aug 2005 13:02:55 GMT, "Roger Derby"
wrote:

Just be careful when creating "hard points" that you spread the load
smoothly out to the skins. Any abrupt change in loading such as occurs at
the edge of a metal backing plate will lead to failure in that area.

Prime areas for concern include deck attachment points and bulkhead to skin
joins.

Would these need to be a fixed hard point on the pontoon top? Could
these be made flexible somehow? Rubber mount points with steel pins
perhaps? I can see the pontoon top flexing and cracking with a small
hard point with a sub-standard backing plate. Could bulkheads in the
pontoons be inceased in size or more placed in the pontoon to help
overcome the flexing? I would like to attach the deck directly to
hardpoints at the bulkheads of each pontoon. The idea was to have a
bulkhead in the pontoon at every other deck mount point. If the deck
is 18 feet long, i could space the bulkheads at 24" apart inside each
pontoon. I could space the deck supports at 12" on center and bolt
through every other one to the pontoon tops. I think that 24" on
center at the deck supports is too far apart and would make for a
spongy deck.


Big epoxy fillets are good; as are stacked backing plates of decreasing size
with the largest and limpest next to the skin.

The larger the better?


Thanks Roger.....

M Russon