There was a time when selecting the correct boat rope for a specific task was scarcely more complicated than choosing a larger diameter for higher loads.

But as new materials have been developed – offering differing characteristics, woven in different ways, with or without a jacket – deciding on which rope is right for you can be something of a minefield.

Typically, the better a rope performs in any number of areas, the higher the price tag, so for most sailors there is something of a cost-benefit analysis to be made when deciding which product to buy.

It is wise to ask yourself what specific improvement you are paying for and whether, ultimately, it is worth the additional expense.

It is also worth noting that, though we tend to equate cheaper with lower performance, that is not always the case.

Sometimes picking up a more expensive rope assuming it will behave better due to the higher price tag can leave you 
with an inferior product for a specific task.

On the other hand, due to the cost price of the materials they use, manufacturers don’t tend to vary hugely in terms of outright price charged for a given product.

As such, if you manage to find a rope that is significantly cheaper than everyone else online, it is worth being fairly cautious.

Rope is our most important tool and for most cruising sailors, a knowledge 
of the basic types established half a century ago has been enough to get by.

Traditionally, we’ve accepted what manufacturers or riggers gave us, perhaps made a decision about nylon rather than polyester for the anchor, and that’s been the end of the matter.

But progress in the past decade or so has been meteoric, driven largely by race boats. Some of these developments lie beyond the needs of cruisers, but the critical elements are right up our alley.

What’s changed and why

We’re now relatively used to seeing the term ‘high-modulus’ in reference to ropes.

These have been used at the highest end of sailing for well over 20 years, though until relatively recently were only available at eye-watering prices.

The term ‘high-modulus’ refers to Young’s Modulus of Elasticity.

The higher the value of this figure, 
the less a rope will stretch.

As it happens, most high-modulus ropes are also exceedingly strong – at least equivalent to wire – and can withstand far more load than any ropes previously.

Not only are these ropes unbelievably strong and light, they also repel water, so won’t get heavier when wet.

The same may not apply to the cover, depending on what this is made of.

The essentials remain the same as they have for a generation, though, with the high-modulus option best seen as an important bolt-on.

Polyester three-strand rope

Once the mainstay of yacht ropes, 
three-strand polyester is now largely used for shorelines.

Stretch is relatively low, price is not too steep and abrasion resistance is reasonable, so if that’s 
how you like your shorelines, it’ll do nicely.

If you prefer more flexibility, try polyester multi-plait or ‘octo-plait.’ It seems to resist chafe better than three-strand, and if one strand does wear through, there are another seven to go.

Polypropylene three-strand rope

This is a cheap and not-too-cheerful option for shorelines.

It chafes easily, is degraded rapidly by sunlight and isn’t 
as strong as other rope variants.

Where polypropylene excels is in 
its ability to float.

As long as you 
have bought the best you can find (the really cheap line won’t coil at all), it will make a great heaving line as it isn’t too heavy to throw and won’t sink into your propeller.

Nylon rope

Nylon, whether three-strand or multi-plait, is the strongest of the non-hi-tech ropes and is set aside from the others by its remarkably low elastic modulus.

This means that if it takes a snatch load, it will elongate rather than break, making it the top choice for anchor rodes and snubbers ever since it was invented.

For shorelines, many prefer polyester or really meaty polyprop because, the argument goes, you don’t want them stretching to leave the boat hanging off the dock.

However, nylon can be a better option because it soaks up any snatching and, so long as you’ve bought nylon that’s big enough for your boat, stretch won’t be an issue.

Nylon is also a very good option for gybe preventers. The less a preventer stretches, 
the more likely it is to damage the boom in a crash gybe.

Nylon has long been the default rope for all running rigging in cruising yachts.

It might be ‘braid-on-braid’, with similar outer and inner 
parts, as sold by most manufacturers, 
or it could be a low-stretch polyester braidline (LSP) with a loosely laid 
three-strand core, such as Marlowbraid.

The stretch reduction of this can be as much as 40 per cent, which is well worth the extra you’ll pay.

Much of the braid-on-braid now sold is pre-stretched at the factory, which creates rope that’s an improvement on non pre-stretched lines, but it’s not as good as LSP, so is less than ideal for halyards on all but the smallest yachts.

With respectable strength, easy splicing and good price, braid-on-braid is the logical option for working sheets, kicker tackle, pole guys and the like.

It starts off soft to handle, but it can stiffen up over the years until the friction it creates passing round a block becomes so heavy that the boat’s winches are inadequate.

It also chafes relatively easily and it stretches a lot compared with more modern alternatives.

Buy Marlow Rope’s doublebraid rope on Amazon (UK)

Buy Kingfisher Braid on braid from Force 4

Buy Liros braid on braid from Force 4

Note: We may make a small commission on purchases made via the links on this feature. In no way does that affect our editorial independence.

Cores and modern rope

Modern ropes are made of two components – a core that accounts for up to 95% of the rope’s strength, plus a protective outer cover (or jacket) that provides abrasion resistance, protection from sunlight and, where appropriate, improved holding in a clutch, jammer or cleat.

The cover can also be designed for better handling comfort.

On racing boats this will 
usually be sacrificed in favour of a performance benefit, be it holding capability or resistance, but for the cruising sailor, striking a balance between performance and comfort 
is a key concern.

Broadly speaking, when talking 
about modern ropes, there are four or five major fibres involved – primarily Dyneema, Technora, Kevlar and polyester.

Until recently, Vectran 
was also used frequently, but its low resistance to ultra-violet light means there are now better fibres on the market.

These materials are blended together in different ways to produce both cores and covers that are optimised for each function on the boat.

Dyneema focus

Dyneema is perhaps the most important fibre currently used to manufacture ropes and is a proprietary brand name 
of DSM, which developed and sells it.

As such, brands selling Dyneema products will almost always feature the Dyneema name and/or trademark.

Dyneema is not the be all and end all of ropes but it does cover most areas and is a reliable purchase thanks to the above reasons.

All of the ‘big four’ manufacturers working in the UK – English Braids, Kingfisher, Liros, and Marlow – feature Dyneema in their performance products.

Dyneema lines come in different types too.

So simply specifying a Dyneema line of an appropriate size is not sufficient. Dyneema sells four different types of fibre for the marine sector: SK75, 78, 90 and 99.

SK75 has been around a while and combines strength with lightweight.

SK78 is a higher-end product with lower creep (permanent long-term elongation that arises from extended periods under load), while Dyneema SK90 has more strength, but with slightly more creep.

Continues below…

In recent years Dyneema SK99 has 
been making significant inroads into 
the racing world and is now used by all major manufacturers.

SK99 has become one of the class leaders in the rope rigging field and offers a breaking load 
of almost a tonne in 3mm rope!

For most cruising sailors, however, 
the latter would be overkill, says Nigel Saddington of Kingfisher Rope.

‘I would say that 78 has superseded 75 and 99 has superseded 90 right now. But even then, to be honest, for most sailors and in most circumstances, I would say 78 
is sufficient for almost all needs.’

Buy Marlow Excel Fusion Rope – SK75 Dyneema core – from Force 4

Buy Liros Magic Edge Rope – SK75 Dyneema – from Force 4

Effect on deck fittings

Nigel points to some concerns he has with the very top end of the Dyneema ropes being produced.

He notes that as 
a commercial product, its strength and stiffness are the qualities that make it a good rope but also make it a rope to be used with care.

This is because the loads that can be carried, even in a relatively small-diameter line, are high enough to warrant extra consideration 
with regards to which clutches and sails it is being used with.

This is a theme that seems to pop-up time and again in recent years; as modern materials become stronger, so the rest of the kit on board needs 
to be up-spec’d in order to keep up.

Though it is impressive how much load can be carried by the highest-performing ropes, in relatively small diameters you still need something wide enough for your clutch to hold, and you will also want to ensure that your deck gear is rated high enough to deal with the loads.

Saving a halyard at the cost 
of losing a clutch might not be such a good idea.

Cover

That basic core of modern ropes 
isn’t the only area where there have 
been developments, however.

Here, a Dyneema mix is a popular option which has the benefit of being extremely light and, perhaps because it floats, is as resistant to water as the Dyneema inside – great for lightweight spinnaker sheets that stay light even after they’ve been dunked a few times.

The downside is that it doesn’t last very long because of the vulnerability of polypropylene
to UV degradation.

The ‘entry-level’ coat is polyester 
of similar specification to the standard braid-on-braid most of us use.

This is relatively loosely woven, making for easy splicing.

Although 
the resulting rope’s performance is streets ahead of its braid-on-braid equivalent, it is prone to chafe and is more likely to slip around the core.

In other words, 
the clutch catches the cover but the 
core can slide through until equilibrium is reached.

Next up the scale comes Technora, 
a para-aramid fibre woven far more tightly.

A coat of this is a little more expensive than a basic polyester cover, but the improvement in performance and chafe-resistance is huge.

If your halyards are wearing through and need replacing, it’s a no-brainer.

Finally, if you want to see your ropes in the dark, you can specify a cover that has a light-positive strand.

This works on the same principle as those garden lights that soak up power by day then illuminate when it’s dark.

The rope won’t dazzle you, but you’ll certainly appreciate being able to see it so easily 
at night.

What ropes to use in running rigging

On most cruisers, sheets and other ropes that are constantly adjusted and not under tremendous load can sensibly be braid-on-braid for economy, ease of splicing and soft feel.

Lines that are set up tightly then left are a different story, however.

On a boat with pretensions to performance, high-modulus ropes can make a dramatic difference.

Reef pennants are a case in point.

A Dyneema pennant can be a size or 
two smaller than the standard braidline item, yet will be just as strong and will stay tight once set up.

Main halyards should definitely be made out of some variety of Dyneema, ideally with a Technora coat or its equivalent.

Wire halyards are a thing 
of the past now, particularly when rope can cope with almost the same loads 
for its size, with few of the drawbacks.

Headsail halyards should also 
ideally be top-quality rope, but on roller forestays it can be easier to maintain luff tension than on a mainsail.

So, if funds are tight, upgrade the main halyard first and see how you get on.

Creep stretch and elasticity definitions

Initial loading will result in elastic extension.

This happens upon loading and is immediately recoverable upon release of the load (elastic contraction).

After the elastic extension 
of the initial loading, the rope 
will experience what is known 
as viscoelastic extension.

This is further extension over time and is fairly limited.

Unlike elastic stretch, viscoelastic stretch will only recover slowly over time once the load is released.

Finally there is creep, which is permanent, non-recoverable and time-dependent.

Creep occurs at the yarn molecular level when the rope is under constant load.

Once the load is released 
and elastic and viscoelastic extension recovered, the rope will ultimately have experienced an element of permanent extension.

This is a factor of 
both creep and ‘bedding in’, which is when individual fibre components in the rope and/or splice settle into their preferred position when under load.

Enjoyed reading Rope, rigging & deck gear: how to choose the right rope?

A subscription to Yachting Monthly magazine costs around 40% less than the cover price.

Print and digital editions are available through Magazines Direct – where you can also find the latest deals.

YM is packed with information to help you get the most from your time on the water.

• Take your seamanship to the next level with tips, advice and skills from our experts
• Impartial in-depth reviews of the latest yachts and equipment
• Cruising guides to help you reach those dream destinations

Follow us on Facebook, Twitter and Instagram.