Oblique versus level windlasses
Both raise a weight equally per turn, but the oblique drum gathers twice the cord and ends lower
Folio 168v turns to the argano (windlass or winch), comparing an oblique drum c d with a level one a b. Leonardo argues that, with cords and drums of equal thickness, both raise their weight equally high per turn, though the oblique drum can gather twice as much cord while its last coil ends lower. He adds that a longer cord and a more acute angle make the lift slower, that the windlass pulling between more unequal angles gathers the most cord, and that gathering more cord means raising the weight less high. The right-hand sketches show cranked winches with cords and hanging weights, numbered 39 to 41.
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Oblique versus level windlass
The oblique windlass c d raises its weight, turn for turn, as high as the level windlass a b when the cords and drums are of equal thickness. The oblique one can gather twice as much cord, but its last part remains so much the lower.
Cord length and angle govern speed of lift
The longer the cord m o is than the cord a n, the more slowly it raises its weight; likewise the more acute the angle b compared with the angle r, the slower the motion of b than of r.
More cord gathered means less height gained
Among windlasses of equal thickness, the one that pulls between more unequal angles gathers more cord; and the windlass that gathers more cord raises the weight less high.