Which fibre for which application ?
Which rope should be used for your ropes, halyards and mooring lines? Choosing the right fibre according to its use, guarantees your ropes’ performance, durability and reliability. Ino-Rope has established a comparison between different types of fibres to guide you with your choices.
Comparative table of different fibres
Polyester: The all-round fibre
Its excellent value for money explains the success of this fibre, which is oil-derived. Mass production in the textile industry has led to slashed prices. The principal quality of polyester is its longevity: high resistance to UVs, as well as to chafing. In fact, this characteristic makes it ideal for protecting delicate cores: Nearly all the covers on the market are either made of or contain polyester. Its only fault is its elongation to break (elasticity), which can vary between 8 and 12%, according to the quality of the fibre. In this respect, one should favour “high tenacity” polyester, whose elongation is inferior to that of average quality polyester. Perfectly suited to a cruising programme, polyester halyards and sheets are not a panacea in regattas, as the elasticity of the lines affects the precision of settings. Find our Polyester ropes here.
Quality / cost/ longevity ratio
Elongation at break (for regatta)
Polyamid (Nylon): ideal for mooring lines
If you want to show off in front of your friends, use the word “polyamide” to speak about this plastic material that is a hit on the textile market. If that was a flop because your friends already knew that polyamide was mostly known by its trade name Nylon®, you can save face by specifying that the word corresponds to the abbreviations of New York and London, the two factories of the American company Du Pont de Nemours that discovered the fibre in the mid-thirties. Compared to polyester, polyamide has an elongation to break, which is significantly higher (from 15 to 20%). Its high elasticity makes it particularly suitable for mooring, as its fibres protect the cleats by absorbing shocks. However, a polyamide mooring line is heavy to handle because this fibre is very dense and absorbs water.
Polypropylene: towing line
With comparable elasticity to polyamide (Nylon ®) polypropylene is, however, hydrophobic. Some fishing nets profit from the specificities of each fibre. The top part, made of polypropylene, floats, while the polyamide bottom part absorbs water and sinks. Polypropylene ropes are perfectly suited to towing operations (Sea Rescue, sailing schools, traction water sports) because they are elastic and float. Therefore, they cannot get caught in propellers. Remember the early days in water skiing, when you had to hold on tight to the handle, as if your life depended on it. You didn’t know it then, but you had polypropylene in your hands. Despite its elasticity, polypropylene cannot, however, be used for mooring lines because, as well as being very stiff in hand, it is UV sensitive and ends up disintegrating into dust.
Plaits (Kevlar®, Technora®): pioneers in textile standing rigging
The Aramid fibres are part of the family of fibres with the exotic name: “aromatic polyamide” . Commercialised under the brand name Kevlar® by Du Pont de Nemours in the 1970’s, Aramids, whose resistance to impact is excellent, have namely been used to manufacture individual protection equipment (helmets, anti-cut gloves, bullet-proof jackets… ). In the boating world, Kevlar® or Technora® (the competitor’s brand), are appreciated for their very high breaking strength, their low elongation to break (about 3,5%) and their unpaired stability under static load (no creeping). In other words, these fibres are very solid (five times more than stainless steel), with nearly no elasticity and do not stretch over time. The first textile standing rigging was made of Aramid fibre. In membrane sails, the stability of their shape prevents deformation of the sail profile. Their heat resistance (point of destruction at 450°C) enables the fabrication of covers which do not melt when easing sheets brutally on a winch. The only cloud in the sky (besides their price), is that Aramids have low resistance to UVs.
High modulus polyethylene (Dyneema®, Spectra ®): a fibre of the future
If the chemical name “high modulus polyethylene” means nothing to you, you have certainly heard of Dyneema® or of Spectra®, the two brands marketed respectively by DSM Dyneema™ and Honeywell™. With similar elongation to break but a breaking strength superior to that of Aramids (eight times more than stainless steel), high modulus polyethylene soon replaced them in industry (oil rig moorings, for example) and military use. The advantage of Dyneema® is that it resists as well to UVs as it does to abrasion (it is, thus an excellent cover) and to intense bending radius. Its behaviour under static load has, nevertheless, caused problems: subjected to continuous significant tension, the fibres have stretched irreversibly (creeping). However, improvements in fibre manufacturing and treatment techniques (heat set and pre-stretched process) have enabled the stability of Dyneema® to be considerably increased. The latest technological innovations have enabled the elaboration of a particularly stable Dyneema® (with no creeping) suitable for standing rigging. Today, Dyneema® is commonly used in leisure yachting even though its cost remains high.
PBO: Efficient but so fragile!
Polybenzoxazole is not Captain Haddock’s latest swear word but a fibre invented and marketed by the Japanese company Toyobo. Its remarkable rupture resistance, its insignificant elongation to break (elasticity), as well as its excellent mechanical and thermal stability, explain the success of PBO, which soon replaced Aramid fibres (Kelvar® and Technora®) for military use. But PBO has almost as many qualities as weaknesses. As well as costing an arm and a leg, this fibre has a short lifespan: it neither withstands UVs, nor chafing (the fibres undergo self-abrasion, rubbing against each other), or humidity (how convenient at sea!). Its very high density significantly increases the weight in the tops, which hinders the sailing yacht’s performance. In brief, PBO has got it all wrong! Much lighter, more durable and affordable, in the next few years, Dyneema® should rival with PBO, in the field of textile standing rigging fabrication.
Carbon: a premium fibre
This oil-derived fibre is quite simply amazing. With stiffness and mechanical stability that withstand any conditions, carbon is also ultra-light weight and entirely UV insensitive. As long as it is not exposed to shocks, its lifespan is virtually unlimited. While it is extremely stiff, carbon is very breakable, and as it is coated with resin, this makes it sensitive to shocks. A part from this weak spot, which requires rigorous and regular follow-up of standing rigging, carbon is a fibre with exceptional qualities – dedicated to outstanding sailing boats. Carbon standing rigging (made of parallel fibres) is a privilege for offshore racing and more so, of the elite offshore racers (IMOCA class, Volvo Ocean Race… )!
