The importance of choosing the correct rope

When the moment comes to choose or replace the ropes of our boats, we often find ourselves overwhelmed with the wide variety of products available. In the last twenty years, the world of textile ropes has undergone a big evolution and the availability of high resistance and high modulus fibre has made the development of many new products possible. All these new products have joined the selection already available, making the process of choosing a rope a very complex process.

The first tip

The first tip is to identify your own priorities: even if it seems obvious, carefully evaluating how the boat will be used most of the time will help you find the most suitable product. It would be useless to have an extremely high-performance sheet that is less than “friendly” on your hands if you are only going to participate in a boat race once every couple of months. What is decisively more important is that it is comfortable to use and has a good performance for its main use. Keep in mind that most rigging on-board will require a good capacity to bear load and a low elongation.

The budget

The budget dedicated to the purchase of ropes is just as important: it will help us define the type of products to take into account, cutting our choices down. I like to make comparison with the car industry, which is easily understandable; just like our tires have to transfer the power from the engine onto the road and guarantee traction and safety, our ropes, in the same way, have to transfer the power of our sails and equally guarantee safety and performance, perfectly complementing the equipment on-board.

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After forming an idea of what requirements your rope should meet, we need to understand what kind of fibre and type of rope construction would satisfy your needs. Undoubtedly a large part of the performance properties of a rope lies intrinsically within its fibres.

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The type of fibre and the construction of the rope can be selected in different combinations to suitably meet your demands. Bear in mind that the selection process often requires compromise with regards to performance and cost. Therefore, carefully evaluating your own priorities is the first step toward the right choice of the “best” rope for your use and not the “best” rope in absolute value.

Listed below are the main properties of the fibres with which most ropes are made:

  • Polyester – polyester fibres are characterised by their high strength, being light-weight, and resistance to wear and tear. Polyester is also resistant to kinks and chemical and physical agents. All these properties, combined with a low coefficient of liquid absorption, makes this material ideal for many different uses. 
  • Polyamide (Nylon) is a material characterised by its resistance to wear and tear, high strength and especially its remarkable elasticity. Polyamide fibres are suitable in situations which require high elasticity, like for mooring lines or mountaineering ropes for example. 
  • Dyneema® – UHMWPE (ultra-high molecular weight polyethylene) – developed and produced by the Dutch company DSM, Dyneema® is often confused with Spectra®, a similar material but with a slightly lower performance.  Dyneema® is a high modulus polyethylene with exceptional properties with regard to strength (for the same weight, from ten to fifteen times stronger than steel depending on the type), modulus and resistance to abrasion. This remarkably light weight material (having a lower density than water) also guarantees excellent resistance to chemicals and environmental agents, and has a great lifespan. The only true drawback to this material is its limited resistance to temperature. 
  • Kevlar® is an aramid fibre whose trademark belongs to DuPont de Nemours. This fibre, recognisable by its characteristic yellow colour, is characterised by a high modulus and a high heat resistance (it breaks down without melting at around 400° centigrade). Kevlar®, for the same weight, is five times stronger than steel and guarantees good stability when bearing load. This fibre is sensitive to UV rays.
  • Vectran® (Liquid Crystal Polymer) is a polyester based on liquid-crystal technology produced by Kuraray Co.Ltd. This fibre is characterised by a good resistance to abrasion and temperature, and being strong and having a high modulus. As well as guaranteeing a low moisture absorption, Vectran® is also very stable when bearing load, displaying an extremely low creep – until 50% of the breaking strength. This fibre is very sensitive to UV rays.
  • Technora® is an aramid para-fibre that is developed and produced exclusively by the chemical company Teijin Limited that made it available on the market in 1987. This fibre has, amongst its main properties, a high tensile strength, a high elastic modulus and an excellent resistance to heat and chemical agents. For the same weight, Technora® is 8 times stronger than steel and 3 times stronger than polyester fibreglass and nylon. Compared to other high-strength fibres, Technora® has an excellent resistance to fatigue. Technora® has a rigid and specialised molecular structure that gives it a high elastic modulus, low creep and low stress-relaxation. Technora® exhibits a high resistance to acids, alkali and organic solvents. It is also resistant to steam and sea water. 
  • CORDURA® by INVISTA belongs to the Nylon 66 family, with a high resistance and strength. Known for its excellent strength-to-weight ratio and for its exceptional resistance to abrasion, CORDURA® fibre is the ideal choice for situations in which a good grip and excellent strength is needed. 
  • PBO, commercially known as Zylon®, produced by the Japanese company Toyobo Co., is characterised by its strength and modulus that far exceeds those of aramid fibres. It also stands out for its remarkable stability under constant load, which allow it to be used as a substitution for steel bars in standing rigging. It can be easily recognised by its characteristic gold-yellow colour (darker compared to Kevlar®). This fibre displays a high resistance to abrasion and especially an excellent resistance to heat, enduring temperatures higher than those endured by aramid fibres. PBO Zylon® is, however, very sensitive to UV rays and moisture.

The ropes quality

You should certainly not try to economise when purchasing your set of ropes. As mentioned above, the performance and security of your boat are directly correlated to the quality of the ropes. The manufacturing companies invest time and money so that they can offer you the right rope for every part of the rigging on-board. This results in an advantage for users in terms of performance and lifespan. Choosing the wrong material or the cheapest material can prove more troublesome than accepting the expense of purchasing the correct product for each situation. Buying a sheet with a completely Polyester cover on a part of the rigging that bears a lot of load and where there is lots of friction on the winches can result in premature wear and tear on the cover and a fusion of the fibres due to the heat generated by the cover/winch grip. Investing in a “cover” tactically made of a blend of heat and abrasion resistant materials can be extremely convenient in the medium run. In many cases, putting your faith in the expert hands of a rigger or a distributor is often the right choice.

Some example

We can now provide some examples, taking the necessities of the modern cruiser-racer into consideration and evaluating where to best spend our available budget.

The evolution of materials in halyards has shown the most obvious differences and the benefits of higher quality halyards are evident even on a cruise ship. There is no doubt that replacing polyester halyards with Dyneema halyards immediately brings certain benefits. The first is the possibility of reducing the diameter of the rigging, providing that the equipment on-board is suitable for a reduction in diameter. It is not uncommon to have problems linked to a slipping rope clutch caused by smaller halyard diameters. Clutches are designed to maximise their workload with the largest diameter line that they can accommodate. There is a significant advantage in terms of weight when using higher quality halyards instead, even in cases where diameter is not being reduced. Keep in mind that in the case of halyards, any reduction in weight is lost at the top of the boat, which improves boat stability.

Undoubtedly, another advantage in using halyards with Dyneema cores is the lower elongation which allows better control of the sails, yielding better performance. My personal suggestion is to not relegate Dyneema to the main and jib halyards where the benefits are the greatest, choosing a good polyester halyard for a gennaker or a spinnaker in the case of a limited budget instead. 

As for the sheets, the adoption of Dyneema also brings all the advantages listed above, but in this case, it is important to pay close attention to the constitution of the cover. If it is true that good polyester guarantees a good all-round rope, a mix of higher performance fibres can help solve specific problems and enhance the performance and comfort of use. For example, if we take sheets for a genoa sail or a jib sail used on modern and high-performance boats, the polyester cover already degrades significantly after the first few uses. This is all the truer the newer the winches are. The work load to which the sheets are subjected combined with the friction generated on the warping end of the winch makes polyester an unsuitable material. This is why, in recent years, we have seen mixes between polyester and so-called exotic fibres like Kevlar or Technora becoming more and more popular. These fibres, being particularly resistant to heat and abrasion, guarantee a longer lifespan and a better feeling when adjusting the sheets.  

We could write hundreds of pages on mooring lines with hundreds of anecdotes and experiences that could entertain you for hours. In this article, I would like to highlight the fact that mooring lines are what you see first when you see your boat. They are also what ties your investment to land. Deliberately choosing a good quality mooring line will help you sleep better at night, not just metaphorically speaking. Moorings that creak and make noise will certainly decrease the quality of sleep of both you and your guests. This is why it is advisable to opt for a double braid rope, combining the elasticity of a Nylon (polyamide) core with a more flexible construction, that steadies the movements of the boat in a softer and more silent way.

What has been outlined in this article is intended to be the starting point of reflection on the importance of choosing ropes, something that is too often considered as simply an accessory of lesser importance. Considering the impossibility of exhaustively dealing with this topic in-depth in such a short article, I have decided to instead list some points to consider in the hopes of having sparked your curiosity and raised awareness of your needs when purchasing your next ropes (possibly assisted by an expert rigger with some valuable advice).

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