Ropes and Rope-Making
Ropes are made by twisting together 3 or more strands which are themselves formed of twisted yarns. The oldest ropes are said to be made out of flax fiber. There are papyrus ropes in the British Museum that are about two thousand years old. Many vegetable fibers have been used in ropemaking, including date palm, flax, jute, cotton, hemp, and coconut fiber. Towards the end of the nineteenth century, manila was introduced and this some became the most popular ropemaking fiber.
Ropes are carefully designed so that applied loads are equally shared between the sheath yarns and the core yarns. Natural fiber ropes used in old wooden tall ships were made from yarn which had been spun from raw fibers. The material is fed into a machine which combs the fibres with steel pins and produces a coarse sliver. The slivers are spun into yarn and then made into rope with a right handed(Z) or left handed(S) twist.
A manual method of making rope is by means of a ropewalk which is a path along which rope-forming strands are laid. The strands are drawn out by a traveller and when they have been drawn to the correct length the rope is closed by means of a top-cart, which is returned from the traveller end to the register plate end at a regulated speed.
The amount of twist in a rope is called the lay. A hard laid rope having more twist put into the strand and rope than a soft laid rope. A 3 stranded rope is known as plain or hawser laid. A 4 stranded which is useful for rope ladders is known as shroud laid. Cable laid ropes are made from 3 or more stranded ropes, and the twist direction is again reversed. That is, Z twisted ropes would be laid with S twist.
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