Köis

Köis is the Estonian word for rope or line, a flexible element made by twisting or braiding fibers into a continuous strand. It is used to transmit force, bind objects, lift or lower loads, secure equipment, or guide movement. Ropes exist in natural and synthetic varieties and come in various constructions and sizes.

Materials range from natural fibers such as hemp, sisal, cotton, and manila to synthetic fibers including nylon, polyester, polypropylene, and high-strength fibers like UHMWPE and aramids. Natural-fiber ropes are inexpensive and provide good grip but are susceptible to water absorption and rot. Synthetic ropes offer higher strength-to-weight ratios, greater durability, and often lower stretch, though some are sensitive to UV exposure and chemicals.

Construction types include laid (twisted) ropes, which consist of multiple strands twisted together, and braided ropes, which are woven for a smooth sheath. Ropes can be designed for static use, which minimizes elongation, or dynamic use, which intentionally allows stretching to absorb energy (important in climbing and rescue).

Common classifications by use include marine, climbing, arborist, industrial, towing, and rescue applications. Safety considerations emphasize regular inspection for broken strands, glazing, fraying, or sheath damage; avoiding sharp edges and chemical exposure; storing in a cool, dry place away from sunlight; and retiring ropes that have reached wear limits or suffered significant loading.

Historically, rope-making dates to ancient times with natural fibers, progressing to longer, more durable ropes through ropewalks and eventually the widespread adoption of synthetic fibers in the 20th century.