Rope
A rope is a group of yarns, plies, fibres, or strands that are twisted or braided together into a larger and stronger form.
[4] But synthetic ropes also possess certain disadvantages, including slipperiness, and some can be damaged more easily by UV light.
Synthetic fibres in use for rope-making include polypropylene, nylon, polyesters (e.g. PET, LCP, Vectran), polyethylene (e.g. Dyneema and Spectra), Aramids (e.g. Twaron, Technora and Kevlar) and acrylics (e.g. Dralon).
The current preferred international standard for rope sizes is to give the mass per unit length, in kilograms per metre.
[7] It is of paramount importance in fields as diverse as construction, seafaring, exploration, sports, theatre, and communications.
The use of ropes for hunting, pulling, fastening, attaching, carrying, lifting, and climbing dates back to prehistoric times.
The earliest evidence of suspected rope is a very small fragment of three-ply cord from a Neanderthal site dated 50,000 years ago.
[10] A tool dated between 35,000 and 40,000 years found in the Hohle Fels cave in south-western Germany has been identified as a means for making rope.
[12] Plant fibres have been found on it that could have come from when they fed through the holes and the tool twisted, creating a single ply yarn.
Fiber-making experiments with a replica found that the perforations served as effective guides for raw fibers, making it easier to make a strong, elastic rope than simply twisting fibers by hand spiral incisions would have tended to keep the fibres in place.
[14] Other 15,000-year-old objects with holes with spiral incisions, made from reindeer antler, found across Europe are thought to have been used to manipulate ropes, or perhaps some other purpose.
[13][16] Impressions of cordage found on fired clay provide evidence of string and rope-making technology in Europe dating back 28,000 years.
[17] Fossilized fragments of "probably two-ply laid rope of about 7 mm [0.28 in] diameter" were found in one of the caves at Lascaux, dating to approximately 15,000 BC.
Egyptian rope dates back to 4000 to 3500 BC and was generally made of water reed fibres.
[19] Other rope in antiquity was made from the fibres of date palms, flax, grass, papyrus, leather, or animal hair.
The use of such ropes pulled by thousands of workers allowed the Egyptians to move the heavy stones required to build their monuments.
Remarkable feats of construction were accomplished using rope but without advanced technology: In 1586, Domenico Fontana erected the 327 ton obelisk on Rome's Saint Peter's Square with a concerted effort of 900 men, 75 horses, and countless pulleys and meters of rope.
It is this counter-twist, introduced with each successive operation, which holds the final rope together as a stable, unified object.
[23] Cable-laid rope is sometimes clamped to maintain a tight counter-twist rendering the resulting cable virtually waterproof.
An additional drawback of twisted construction is that every fibre is exposed to abrasion numerous times along the length of the rope.
This means that the rope can degrade to numerous inch-long fibre fragments, which is not easily detected visually.
Some forms of braided rope with untwisted cores have a particular advantage; they do not impart an additional twisting force when they are stressed.
Other specialized cores reduce the shock from arresting a fall when used as a part of a personal or group safety system.
[citation needed] Braided ropes (and objects like garden hoses, fibre optic or coaxial cables, etc.)
This construction is popular for gaskets and general purpose utility rope but rare in specialized high performance line.
Static kernmantle ropes are made with untwisted core fibres and tighter braid, which causes them to be stiffer in addition to limiting the stretch.
It is less prone to kinking than twisted rope and, depending on the material, very flexible and therefore easy to handle and knot.
Rope made from hemp, cotton or nylon is generally stored in a cool dry place for proper storage.
To prevent fraying or unravelling, the ends of a rope are bound with twine (whipping), tape, or heat shrink tubing.
A tugboat operator once sliced the palm of his hand open down to the sinews after the hardened (and obviously sharp) end of a rope that had been heat-sealed pulled through his grasp.
