Folding kayak from salvaged materials

I was collecting broken windsurfing booms and other unwanted things made with aluminum tubing so I could make some kayak carts.  After a while I realized that I might be able to collect enough material to make a folding aluminum kayak similar to the ones at Yostwerks --the Sea Otter, for instance.

I think that I currently have enough tubing--if I include the curved parts of the booms--to make a 15' boat. 

Salvaged tubing from windsurfing booms.

Above is a photo (taken in very bad light) of some of the stuff I've collected so far.  On the far right and the far left, respectively, are a carbon fiber boom and a carbon fiber paddle; these would be for the middle and one end of the keel.  There are two 'orphans,' the broken-off parts of a boom set (that I don't have the rest of), and one of these would form the rest of the keel.

There are two complete pairs of booms (including the sliding\adjustable part that attaches to the clew of the sail), and these would be for the gunnels.  I have three lengths of 5' by 1" tubing, and the excess tubing from the keel and gunnels construction, to make a pair of chines.

The bulkheads are going to be made from preformed aluminum parts from a walker and from another thing with a similar shape that I rescued from a dumpster.  (Update: the bulkhead frames at the ends will be made with 1/2" HDPE from the scrap bin at TAP Plastics, and the others will be made from white oak.)  These will take some finagling, but they ought to work.  The cockpit could be the hardest part.  I'm going to try bending some 3/4" tubing from crutches (I have several salvaged pairs of these), and if I can't make that work I'll use wood or make an open-style cockpit.

So, I've got all this stuff... and what's stopping me from starting construction of the frame is the design.  I don't know if I can use one of Tom Yost's designs as-is because I want to include the curved parts of the booms in the design, and Tom's designs use straight tubing with a smaller diameter.  I don't think the tubing I'm using will bend easily enough to be used for one of the Yostwerks' boats.

I'm stuck for now, but eventually I'll come up with a plan that I think is adequate and start cutting stuff up, and if I get that done (without a strongback, since I don't have the materials or budget to build one) I'll start think about how I'm going to skin the boat.

Update:  I got some 7' ipe  deck planks to make a strongback from, but I'm still stalled until I can clear away enough junk to have room to set up the strongback.  I found a possible source for skin material, but I haven't been able to get it home from the junk store.

Update:  I no longer have a place to set up a strongback, so this project has been stalled for months.  I have a set of frames for a Sea Tour 15, but not much else is done.