Fibre Ropes - What are the different types and how to choose them? (2023)

Fibre Ropes - What are the different types and how to choose them?

Monday, 27September2021

The term ‘Fibre Ropes’ covers such a broad range of rope and sling materials it can often become confusing to the newcomer.

Fibre Ropes can be made from many materials ranging from the most ancient to the latest synthetic technology.

Each rope has special properties, and these vary enormously with the material chosen. It is important to recognise these differences, because using the wrong fibre material in critical applications may result in disastrous consequences.

Types of Fibre ropes

Classifying fibre ropes is not a staightforward task. In terms of synthetic ropes there can be multiple names for the same material and many similar names for quite different materials. Natural fibre ropescan be confusing for the same reason.

An experienced person may be able to distinguish between the different types of fibres by observation, but appearance alone isn’t a reliable way to determine the type of rope – manufacturer markings, certification and laboratory testing are more reliable ways.

Natural fibre

The first and most obvious distinct category arenatural fibre ropes. In technological terms these materials are ancient, but they have their own special and beneficial properties which keep them relevant today.

Natural fibre ropes for industrial purposes are typically a 3-strand construction. This, together with the friction properties and easy handling make for ropes which are very easy to splice and user friendly.

They are first classified by the type of fibre used, with Sisal and Manila being the dominant varieties.

Manila (also called Manila Hemp) is made from the abacá plant (a relative of the banana).

Sisal is made from a species of agave plant, the Sisal Agave.

Other fibres can arise including Jute, Coir, Cotton and True (cannabis) Hemp. Although in our industry today they may be uncommon.

A Sisal Tug-o-war Rope

Colloquially, many people call different fibres hemp even though they aren’t actual hemp made from a cannabis plant, this muddies the waters and distracts from important differences between natural fibres.

Synthetic Ropes

Synthetic ropes were once a simpler topic. There were only really 3 common rope material types nylon, polyester, and polypropylene.

Generic names for materials which are well understood can be helpful, and tradenames can also be beneficial. Like many things though, having multiple names for the same or similar things is a source for confusion.

Nylon, one of the older synthetics and once a tradename, is now commonly listed under the generic name Polyamide.

Newer fibres, marketed under their trade names can be difficult to differentiate, as there are also composite combinations of fibres made into ropes. Some tradenames provide notable differences in performance. Names such as Kelvar^TM, Dyneema^TM, amongst others, have certain features and benefits, but are also referred to in terms of generic names: Aramid, and HMPE (or UHMWPE) respectively.

The topic overall is complex, but there are some simple points for the newcomer…

'Silver’ Polyester Rope

Natural fibres are not obsolete

There are a number of reasons why a natural fibre rope solution is preferred. The most obvious one being biogedradability. Wherever a rope must be installed in sensitive environments and there are no means to recover it once spent, there really are no ecologically sound alternatives.

Other reasons include the ease of splicing, and how ‘grippy’ the rope is. It can be specifically preferred for taglines where site rules prescribe as it is generally good to handle and non-conductive. It also has excellent knot holding properties.

If you’re looking for a natural fibre rope that is good to work with by hand – the fibre to choose is Sisal. If you’re after something harder wearing, then Manila is the choice to make.

Can they still be used for slings? This is a complex question, and many people would simply say no. In terms of the rarity of actually needing to use them and the systems required in place to make them interoperable with modern lifting practices, an engineered-lift type solution is suggested.

'Traditional' versus 'new' synthetics

One of the most common arguments cast about in favour of synthetics is how light and strong they are. It’s an argument that’s twisted in every kind of direction, from arguments against synthetics outright - to claims they may be stronger than metals.

A good argument for a ‘new’ synthetic such as an UHMWPE rope that it is much stronger than other soft ropes.

A good argument for an ‘old’ synthetic could be that it is cheap.

Neither is universally true, nor without caveats.

Some ropes are made using a combination of materials, including both new and ‘traditional’ synthetics.

3 Strand Polypropylene Rope

'Traditional' Synthetics

In general, older synthetics are readily available in 3-strand form, this has the benefit of easy splicing methods that anyone can learn and quickly execute without special tools. For general hardware purposes therefore – they are invaluable.

Much like a basic wire rope however, this construction has some undesirable rotational properties. It also can have a fair bit of stretch. This stretch comes from both the construction, and the fibres used.

Stretch might be beneficial in some circumstances, but it also can be a hazard.

The ‘traditional’ and once ever-present polypropylene three-strand rope might have the benefit of being able to float and easy to splice – but it can also store a lot of energy under tension. If something gives way under load, slingshot hazards arise.

Other traditional ropes include Polyester and Nylon. Much like is the case for Round and Webbing Slings, Polyester is a bit easier to find and doesn’t suffer loss of strength when wet like Nylon. However, the two are not interchangeable and chemical resistances are completely different. Polyesters survive many acids, but not alkalis. Nylons are the reverse (alkalis but not acids) and it is best to consult the full detailed list, should there be any chemical exposures of course.

Attributes of ‘traditional’ rope fibres, both natural and synthetic.

'New' synthetics

The star of any sales pitch for Synthetic Ropes today is HMPE (high modulus polyethylene). Its chemical simplicity makes it less reactive to chemicals, its high strength and low stretch makes it a viable substitute for steel ropes in some cases – and, its fibres have a noticeable resistance to cutting.

Within this category the true superstar ropes are those made from brand name high performance variants of UHMWPE (ultra high molecular weight polyethylene) such as various grades of Dyneema^TMfibre. These materials are made with superior quality control and can include chemical tweaks to improve performance. The best tensile performance is typically associated with consistent and very fine individual fibres with high specific strength.

One of HMPE’s Achilles’ heels however is its relatively low resistance to heat.

For heat resistance, we can turn to an older ‘new’ rope – and that is Aramid fibre (commonly known by the trademarked version Kevlar^TM). These fibres gave up their lead in terms of strength to UHMWPE some years ago, as they are not as resistant to chemicals – but they survive heat far better than Polyethylene materials.

It is not uncommon to see materials such as Dyneema^TM and Kevlar^TM used as an element of armour, sometimes literally (as in bullet proof vests) or as protection for slings. They also can form covers or cores for fibre ropes in combination with other materials.

In spite of this, they are not indestructible. Cut resistance is relative, abrasion and environmental effects persist, and sharp corner radius rules still apply.

A rope made from UHMWPE compared with a rope from a combination of polyester and UHMWPE

Types of Rope Constructions

Ropes are constructed in two ways either laid or braided. Laid ropes are twisted ropes as they are made by twisting the fibers together. On the other hand, braided ropes are made from strands that are braided together. You can find a braided rope in several varieties single, double braid and kernmantle.

3-Strand

A3-Strand rope construction makes ropes durable, long-lasting, flexible and easy to handle. For a rope that won’t harden with age, a 3-Strand rope is the best option for you.

Single braid

Single braid rope construction doesn’t generate twist under load and does not kink.

Double braid

A double braided core generates an easy-to-handle rope that is durable. The double braid rope consists of dual parts making it possible to combine diverse fibers to create the ropes merging specific characteristics of raw materials such as a high tensile core with a heat resistant cover.

Parallel core kernmantle construction

Parallel core Kernmantle construction is a unidirectional fiber core with a braided cover that has less stretch but higher strength than the same size double braid line.

3-Strand rope, packaged as coils.

Some pros and cons of fibre ropes

Pros:

• Light
• Inexpensive
• Manual handling is enabled
• Small minimum sheave diameters
• Terminations can be formed quickly without specialised equipment
• Synthetic options can be highly resistant to rot and corrosion
• Bio sourced materials can be eco friendly

Cons:

• Heat resistance may be poor
• Vulnerable to degradation from abrasive dusts
• Acute vulnerabilities to certain chemicals or biological attack exist and vary with material
• May have acute vulnerability to high contact stresses
• Inspections can be largely qualitative.
• Termination efficiencies may vary with skill and technique.
• Some materials associated with plastic pollution.

Fibre Rope Solutions

Nobles is amongst Australia’s oldest continuous stockists of fibre ropes and continue to embrace innovation and technical excellence in delivery of fibre rope solutions. Our experience in testing and ability to offer both the best suited fibre rope and best suited wire rope products gives our customers assurance of the best advice and service when considering fibre ropes.

Nobles stocks a range of fibre ropes including general purpose and high performance.To learn more about our fibre ropes, please click here .

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