Know Your Ropes

Types of Ropes

Rope comes in all shapes and sizes but is generally constructed of one of three materials - natural fibre, synthetic fibre or wire. Originally, all rope was made from natural fibre, then came wire. Since World War II, the trend has been towards synthetic fibre although wire rope is still widely used. Natural fibre ropes have gradually been displaced and are seen only rarely these days. Boats, in particular, tend to use wire and synthetic fibre ropes almost exclusively for rigging.

Natural Fibre

As a general rule, these are composed of the fibres of the leaves and stems of tropical plants or grasses. They are not generally as strong as synthetic fibre ropes and are susceptible to rot when wet. Although fibre ropes such as Manila, Hemp and Sisal are still used for specific purposes, the synthetic ropes have a greater strength and longer life and are thus more widely used.

Synthetic Fibre

Four principal synthetics are used in the construction of synthetic fibre rope - Nylon, Polyester (commonly known as 'Terylene', its trade name), Polypropylene and Polyethylene. Nylon and Polyester are the most commonly used although the other two synthetics have properties which make them ideal for certain work. One of these properties is that, unlike the other two synthetic ropes, they float.

Wire

The two main forms of wire rope are galvanised 'plough' steel wire and stainless steel wire. Both have good properties and are used widely for all kinds of purposes. On board boats, stainless steel is more popular because it does not rust with use. Wire rope is usually in one of two categories - flexible rope which is very workable and allows the wire to be wound around the drum of a crane or winch or through pulleys in a tackle. The stiffer, non-flexible rope which is used where no bending is required, such as the rigging of yachts and radio masts.

Deterioration

All ropes deteriorate with wear, and some deteriorate under the influence of weather or chemicals. Natural fibre ropes, for example, are very susceptible to rot while wire and synthetic ropes are not. However, galvanised wire can rust and synthetic ropes can be seriously affected by heat or sunlight. Chemicals such as acids attack most materials and damage from abrasion is one of the most common causes of deterioration in any ropes.

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