Rope holds together because every layer is twisted against the one before it
Pull apart a piece of ordinary three-strand rope and you will find the fibres twisted one way, the yarns the other, and the strands back again. That alternating counter-twist is the whole secret. Without it, a rope would unravel under load, and its shortest strands would carry most of the weight.
Rope making starts by spinning fibres into yarn, twisting yarns into strands, then laying the strands together, each stage turning opposite to the last. The twist also spreads tension evenly across every strand. Standard rope has three strands with a final right-handed twist, which an international standard labels Z, after the slant of that letter's middle stroke; left-handed rope is S. Right-laid rope should be coiled clockwise, or it kinks.
The oldest possible scrap of cord is a three-ply fragment from a Neanderthal site roughly 50,000 years old, so tiny it needed a powerful microscope to spot; it would not span a little fingernail. From Hohle Fels cave in Germany comes a strip of mammoth ivory, 35,000 to 40,000 years old, pierced with four holes lined by spiral grooves. Experiments with a replica showed that feeding fibres through the holes made stronger, springier rope than twisting by hand. Egyptians hauled monument stones with reed-fibre rope from around 4000 BC, and China used hemp from about 2800 BC.
Ships needed very long lines, since bulky splices jammed in pulleys. From the Middle Ages to the 18th century, Europeans made rope in ropewalks, buildings so long they set the length of a cable, often 300 yards or more. Naval rope carried a coloured strand called the rogue's yarn to identify its owner and expose theft. In 1586 Domenico Fontana raised the 327-ton obelisk in St Peter's Square using 900 men, 75 horses and masses of rope and pulleys.
Knotted ropes even did maths: Egyptian surveyors measured land with them, and some South American cultures kept records on knotted quipu. Nylon, discovered in the late 1930s, first went into parachute cords and glider tow ropes, and synthetics have dominated since the 1950s.
Source: Rope
