I started working on the Aka crossbeams that connect the hulls. These are about 18 feet long. The sides are made of 9mm plywood CNCed to the proper curves. The top and bottom use 58mm x 19mm stock to complete a hollow beam. Various points are reinforced with fir on the inside. The outside gets layers of unidirectional carbon.
This is a picture of the inboard ends of Jzerro's akas. They have a similar design, but a heaver construction. Notice G10 sleeves for the bolt holes.
The outboard ends of the beams have a fairly sharp curve to them. They will need to be laminated fir. It looks like you could bend the 19mm stock this far, but I could not figure an accurate way to clamp everything under pressure while assembling the box.
The 19mm stock will need to be scarfed in a couple places as I have 8 foot lengths. The first order of business was reproducing Russell's scarfing sled so that it would fit the groves on my table saw.
The original is on the left. Mine is more "right-handed".
First trial cut.
Side view.
Ready for scarfing on the bench.
This same setup will be used for stringers and sheer clamps. I'm having trouble remembering if this was 7 to 1 or 8 to 1. I'll measure it later.
My friend Bill helped me rip 12 pieces out of a sheet of 18mm okoume plywood. The 18mm sheet is quite heavy and therefore awkward to handle. The setup for everything takes longer than you might think (at least for a rookie builder).
Task time: 6 hours
Total project time: 111 hours
Total project time: 111 hours
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