Annie has quite enough to do, if Fanshi is to be sailing this year. I offered to make a set of battens, from the 38mm GRP tube that I can get in the UK (there doesn't seem to be a source of equivalent quality in NZ) and Annie has kindly permitted me to do so.
The sail is to have hinged battens, with the panels cambered forward of the hinge and flat aft of the hinge. Both Annie and I are in favour of a sail that is flat in its after half, believing it to be better behaved than fully cambered panels, so all the camber is to be formed in the forward part of each panel.
The batten tubes need reinforcing in way of the hinges, to resist the tendency to burst the tubes. I have done this by first laying up a length of Kevlar tubular braid, then putting on a binding, or whipping, of glass roving, then turning the Kevlar braid back over the glass to enclose it, wetting it out, and winding a length of peel-ply tape tightly over the layup until it is cured. Annie will probably wish to fill and fair these reinforcements, then paint the whole tubes, to keep the UV at bay.
The hinges are turned from 30mm dia nylon 66 bar, glass filled. Both tubes and hinges are cross-drilled at 5.5mm dia, using a bench drill, V block and vice to get the holes central. The holes in the hinges are then opened up with a tapered hand reamer, so that the centre of the hole is still 5.5mm dia, but when assembled, the tubes can take up an angle of 10˚ in the vertical direction as well as 12˚ in the horizontal.
My experience on Tystie was that the battens will tend to misbehave if only permitted to articulate in the horizontal plane; and my experience on Weaverbird has been that though the upper hinges are under compression, and the lower hinges are neither in compression nor tension, when on the wind, all the hinges are tending to pull apart when on a run in brisk conditions. It is difficult to get fore and aft lashings tight enough to resist this, so I have gone back to the bolted hinges that I used on Tystie's battens, but with this extra degree of freedom.
As a bonus, having the battens hinged will make it a lot easier to ship the bundle of finished battens from the UK down under to NZ.