I have been thinking of building sort of a composite-of-designs kayak. My idea is to lay out forms (temporary bulkheads) on a strongback (that's how I understand strip building) and use 2 inch wide 1/8 inch thick plywood strips similar to strip building, perhaps stitching strips together with the thick waxed thread used in sailmaking and leatherworking (or duct tape). Anyone got any ideas or see pitfalls?

> Design work and drafting ability are not a problem - i am a mechanical
> engineer and do design work for a living.

> My question has more to do with developing a hull shape from
> a pattern and vice-versa. When the two hull halves are joined at the
> bottom a fixed angle is created. The remaining edges of the bottom
> and ends are stitched together, the angles at which they join is undetermined
> - they are allowed to float. The gunwale edges spring apart in a shape
> determined by the stiffness of the reinforcing strip and the one or
> two points along the edge where the spread is determined by some beams
> that are put in. The shape of the hull is thus determined by the behavior
> of the plwood as it responds to the stress and finds its minimum-energy
> state.

> I wanted to know if someone had done, or knew of, any means of
> determining the true shape from the pattern and vice-versa, so I could
> achieve (or try to achieve) a particular shape.

> It is possible that, lacking this knowledge, one could lay out
> the lines of a desired shape and develop a pattern (tedious, but possible
> to do with conventional drafting techniques) and then build the boat
> with it. The resulting shape might not resemble the original design
> in the least if the original design hul shape did not reflect the
> shape the hull takes in response to the stress as described above.
>

> It could be done with a finite-element or finite-difference program
> using any of a number of thin-plate models. I could write the program
> myself as I have done for other problems but it would be a bunch of
> work and I hoped someone else had already done it.

> I wonder how hoop pine bending plywood would do. It bends very
> easily along one axis - certainly easily enough to form a hull. It
> would have to be fiberglassed on both sides, though - it wouldn't
> have enough strength of its own.

> I may just do my next kayak in strip-built form - at least you
> get the shape you designed for.

> Bill