In the cooperage shed, Jo Saye and Master Dima spent two hours huddled over a pine workbench. He tested composite stitch patterns with an iron pull-scale.
‘Look at the stress spreading on this tube-shaped sleeve, Master Dima,’ Jo said, showing him a pencil diagram drawn on pipe hub paper. ‘The middle four feet of the sleeve don’t flex. They just hold hoop tension. The only places that experience severe bending shear are the two-inch collars where the fabric clamps to the bronze flanges.’
Master Dima rubbed his chin with his leather-palmed hand, his sharp eyes following her lines. ‘So we use the heavy waxed hemp twine only for the eighteen inches at each collar, and stitch the long straight belly with triple-strand bleached linen shoe-thread?’
‘Exactly,’ Jo confirmed. ‘Double staggered saddle-stitch, three stitches to the inch. It will be slightly thicker and heavier. But the pulling strength across the hoop is ninety-two percent of a solid hemp seam, and it saves fourteen skeins of twine for the ferry fleet.’
They set a six-inch test coupon in the bench vise and hauled on the lever with the iron scale. The linen thread bit deep into the reed canvas, groaning under load, holding firm until the dial reached ninety-eight pounds before the first outer fiber parted.
