Rope making terms can be confusing and often obscure, so here is a glossary of some of the more frequently used words and phrases used in this website or other Marlow or rope-making literature.

Average Break Load: (ABL) The average load at which a rope will break

Bedding in: Permanent elongation that occurs when a rope is first used. Caused by the fibres settling into the most efficient load path.

Braid: Rope construction formed from interlaced fibres spiralling on opposite directions.

Break load: the force at which the rope will break, see Average Break Load, Minimum Break Load, spliced break load.

Coefficient of Utilisation: the coefficient by which a rope or system is de-rated to obtain the WLL. Sometimes referred to as a ‘safety factor’ or ‘design factor’.

Continuous Filament: Synthetic fibres that are extruded and supplied as a continuous unbroken filament.

Creep: Permeant elongation that occurs over extended time, normally associated with HMPE fibres. D:d Ratio – ratio of the sheave diameter (D) and the rope diameter (d)

Design Factor: See ‘coefficient of utilisation’.

Doublebraid: Rope construction consisting of 2 braids one on top of the other.

Elastic elongation: elongation that occurs immediately when a load is applied and recovers as soon as the load is removed.

Elongation: The amount by which a rope stretches (strain). Normally quoted as a % length change at a given condition such as ‘elongation at break’.

Fatigue: Any process that reduces the strength of a rope over the time it is in service.

Grommet: Loop of rope made by splicing the ends together. Often used as a lifting sling.

Heat Set: A stress relaxation process that involves heating a rope after braiding or twisting.

Kernmantle: Rope construction consisting of a core (Kern) and a cover (Mantle). Normally used in reference to climbing and static ropes.

Minimum Break Load: (MBL) a statistically derived figure that represents a minimum strength that the rope should exceed. Normally either 2 or 3 standard deviations below the ABL. Modulus – See stiffness.

Pre stretched: A stretching and heating process that relaxes residual stress and improves performance.

Safe Working Load: (SWL) maximum load that can be applied to a system in a given configuration. May never be more than the WLL but could be less if weaker components or configuration are used. Safety Factor – See coefficient of utilisation.

Seize: Similar to whipping, often used to bind 2 ropes together with smaller cordage, or to form an eye. Splice – a method of terminating a rope.

Spliced Break Load: The break load (either minimum or average) including a spliced termination. Typically Dyneema and other high strength ropes will be testing in this way.

Staple Fibre: sometimes called ‘spun staple’ short length fibres that are spun (twisted) together to create a longer yarn. Can be either synthetic or natural.

Stiffness: measure of the elongation as a function of load. Strand – twisted construction where the fibres are spiral in the same direction.

Stretch: See Elongation.

Viscoelastic elongation: a time dependent and recoverable elongation. Normally associated with HMPE fibres.

Whip: Binding around a rope made with smaller cordage. Used to tidy a rope end and prevent fraying or to secure a splice.

Woking Load Limit: (WLL) Maximum load that can be applied to a rope in a given application, for lifting in the EU this is typically 1/7th of the terminated MBL.