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On 17 Feb 2005 13:43:37 GMT, (William R.
Watt) wrote:
Trying to imagine the least weight way to reduce twist in a light weight
narrow rectangular punt (11'x2'x1') made of thin plywood under
construction. The bottom skids and gunwales are on. There are glued and
screwed chine battens at the intersection of bottom and sides. Three
rectangular building molds are still in. When I torque one end there is
too much twist (flexibility) in the hull for my liking.
I am thinking bulkheads, frames, partial decks, or some arrangement of
stringers. (I opted for the shoebox shape for ease of construction. I know
that curves would have been better.)
Any suggestions?
The lightest, and probably least practical solution, is to box in the
fourth face of the shoe box.
If I recall, that increases stiffness to twisting forces about X100
But how would you sit in or load up?
The next best structural approach is a zig zag of diagonals along the
top. Still not practical.
Getting a shade more practical: if you can introduce a box section
along the keel, or two box sections along each chine that will provide
adequate stiffness. If you could build in those two box sections
along the gunwhales, they would stiffen the hull in probably a most
practical way.
You will be aware that an approach which approximates this stiffening
approach is often used with open top glass hulls:
the gunwhale folds in, then down to make a channel.
Not as stiff as a box, but usable.
Brian Whatcott Altus OK
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