Rapid-Links

An extract from On the Line book

I’m not sure if it’s a Covid thing, but the interest in top rope soloing seems to have grown at an exponential rate over the last few years. Perhaps the reason is the same as the reason bouldering seems to dominate climbing these days, two teams up on a mountain crag generally looking down at a circus of climbers doing their stuff on the boulders below. That reason seems to be a lot of people have time on their hands, but not at the same time, and so people are looking at ways to train outside without a partner or killing themselves free soloing. I also think we’re living in a very anti-social age, not just the covid stuff, but in general, the age of the automated checkout, the delivery driver you can ask to leave your stuff without human interaction. You know what I’m talking about, the way we try and avoid real people because people are difficult, unreliable, annoying. Trying to organise going climbing can be such a pain, trying to work out a path through competing schedules and commitments, why not just go climbing on your own?

This interest in top rope soloing, or self-lining has highlighted a lot of issues, the chief one being that there is no way to do this 100% safely, as it’s all improvised, and ends up requiring a great deal of skill, and yet if often practised by climbers with very little.

Unfortunately, having written two pieces on the subject, I seem to have become some kind of expert, as did Dave Macleod, only Dave was sensible enough to take all his stuff down!

The stuff I’ve written in the past was just an explanation of what I and many have done in the past, which seemed to work and be effective at what you wanted to do, but I can now see that it’s not fit for the world we live in. What’s needed is something that sets out all the information on how to do it, the pros and cons of systems, and the dangers, and sort of press reset, and see if it makes it clearer how to top rope solo. It would also be a good way to set some outdated ideas and misunderstandings straight.

And so, I’ve decided to take a break from writing my current book on clothing (By a Thread), and instead do a short book about top rope soloing called On the Line, which I hope will be done within a few weeks, first on Kindle and Epub (Google Play), and then a small print book.

I’m going to post an extract here for people to read, on the topic of rapid-links, and will be publishing the entire book bit by bit, here, for paid subscribers.

Any feedback would be welcome as the project goes on.

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Rapid-Links

Invented 80 years ago as a way of joining chains together for agricultural use rather than weld a new link, the rapid-link (or Maillon-Rapide, French for ‘fast link’, Rapide, quick-link), soon became indispensable for any job that required high strength, semi-permanent security. 

Although an industrial solution, the rapid-link was quickly adopted by French cavers as a low cost, stronger, more robust alternative to alloy karabiners, as the sport often required hundreds of connectors to be left in situ in a cave system. These connectors would also be subjected to repeated loading, generally, when clipped into sharp bolt hangers, something alloy karabiners are not ideal for, as they soon become damaged, which intern can damage ropes.

The early days of sport climbing and industrial rope access techniques, which were based on caving single rope technique (SRT), introduced the rapid-link to the broader, less subterranean world, with their low cost, but high security, especially when fixed in place, and so establishing them as a core component in climbing rigging, primarily as low cost lower offs on sports climbs. 

Rapid-links are also very low cost, not that cost is important, but their industrial heritage means they can stand up to far more heavy abuse, and neglect, than a climbing karabiner; one is like a sports car, the other a tractor. 

Construction

Unlike a karabiner, a rapid-link has no hinged spring-loaded gate, and rather than being constructed from several parts (frame, gate, spring, rivets, locking sleeve etc), it’s constructed from just two: the frame and the locking collar. 

The frame, or body, is constructed by cutting steel wire to the correct length, then milling a thread on each end, then it’s cold-pressed into the desired shape, which is generally an oval (more accurately a disco-rectangle). 

The hexagonal collar locks the rapid-link closed, and it’s worth noting that as with an oval karabiner, it’s vital that the rapid-link is a closed-loop, so that the load is passed along both spines, rather than one, in order to achieve maximum strength. 

You should also avoid loading rapid-links when open as this could distort the frame in the smaller diameter sizes, making it impossible to close them again.

The collar is hexagonal in order to allow it to be secured by a spanner for maximum strength, with a 12 mm spanner needed for a 7 mm rapid-link, and a 16 mm spanner for a 10 mm link. 

If the link is to be fixed in place, such as on a lower-off, or as a clip-in point, then you should use both a spanner and a little Loctite.  

Although a spanner can be used, for climbing, finger tightening is effective and is the best option if a connector is not to be fixed in place, but regularly removed.  

The tightening and un-tightening can be made easier by adding a few wraps of finger tape to the collar. 

If the collar becomes jammed for some reason, or you wish to close it as tight as possible without a spanner, then a wide opening 7 mm rapid-link can be used as an adjustable spanner, making it well worth including in your rigging kit. 

The lack of a hinged gate means rapid-links have much smaller gate opening, but this is also an aspect of their greater security, as there is no hinged gate to be depressed by terrain features, or by the rope, or climbers body. This comes at the cost of much more limited space for inserting ropes or slings, which is why wide opening designs are recommended, especially if used with thick ropes. 

Once the collar is tightened down it will generally stay closed until you unscrew it, but as with any screw collar, having the rope travelling over it, or rubbing and vibration, can unfasten the collar, but in my experience, unlike a screwgate collar, which can often be found open when you think it’s locked, and visa-versa, rapid-links tend to be far more reliable. 

Materials

Rapid-links come in various materials, including alloy and plastic, but for life support, you want to either use zinc plated steel or stainless steel, with stainless being considerably stronger, but far more expensive, and really designed of maritime use, or by those who want maximum strength and quality.

I would avoid alloy rapid-links unless you have a very certain need for them, as the switch, the alloy means you would need to up the diameter from say 7 mm to 10 mm to get the same strength, as steel models are around a third stronger.

Strength

The strength of a steel rapid-link is considerably greater than most locking karabiners size for size, due to both shape and material, as steel is far stronger and robust than aluminium, plus there is minimal risk of a gate open failure, which is how most karabiners fail. This increased strength, as well as the use of steel, means a rapid-link is also resistant to unnatural or dangerous abnormal loading, such as cross-loading, twisting, bending, or rock impacts, making them ideal connectors for TR soloing, attaching rope soloing devices to the climber’s harness, where such forces can easily take place.

Security

Although a piece of safety equipment can be trusted 100%, and so needs to be monitored, a rapid-link that has been securely fastened shut can almost be considered as a closed link in the system, not that it cannot be opened accidentally – because it can – but because of its ability to hold up to abnormal loads. 

Nevertheless, before climbing, all rapid-links should be checked.

Rapid-links are much smaller in size, but with an equivalent or greater strength, making them less lightly to catch on terrain, snag, and become misaligned. The size difference is offset by the fact the rapid-link will generally be heavier than an equivalent karabiner, although the minimal number required for top rope soloing makes this a moot point.

Shape

Unlike a modern karabiner, which can be hot or cold forged into all sorts of shapes, a rapid-link is like an old-style karabiner, a bent length of bar. This means the available shapes are more limited, being the primary shapes being oval, both standard and long (wide opening), delta (D shaped), triangular, trapezoid, and twisted. One new shape on the market is Kong’s asymmetric model, which is shaped more like a modern hybrid D HMS karabiner, giving it a larger volume at the working end, making it more suitable for wide-bodied devices.

Cost

When buying rapid-links, be warned that not all links are the same, and some links are far below the strength or quality required for climbing, the sort of thing you’ll find in DIY shops. High strength rapid links should either be stamped ‘EN 12275’ for mountaineering PPE or ‘EN 362’ for Industrial PPE, and have the strength stamped on them, either in kilo Newtons, or their safe working load (or working load limit).  But stamps should signify a minimum major axis breaking strength of 25 kN, and an 8 kN minor axis in a 7 mm rapid-link, although some will be far stronger than that (a 10 mm rapid-link has a major axis strength of 50 kN). The best way to get the correct rapid-link is to buy from a trusted source, either a climbing or caving manufacturer or supplier, or look for rapid-links from the French company Peguet. 

TR Solo Rapid-link 

There are two primary potential uses for rapid links in a TR solo system, one as a replacement for the primary device connector, the second, as a way to connect an extension to your harness. There is also a third option that I will cover.

Device connector rapid-link

Although heavy, a standard 9 mm or 10 mm rapid-link can make a very strong connector between your belay device and your belay rope, and removes any fears about cross-loading, and being small in size shortens the distance of any fall. It’s important to avoid smaller diameter options, which although strong enough for the job, will not stabilise the device as well as a larger, more karabiner thickness, rapid-link.

These advantages are offset by the fact that such a rapid-link is more fiddly to use, and it’s down to the climber to decide if this option is better or worse than using a locking karabiner. 

Harness Extension Connector

Although some climbers attach a short sling to their harness by simply larks footing a sling to their belay loop, or through both the legs and waist of the harness, or tie in point, it is much safer to connect a wide opening 8 mm quick-link through the tie in point, and then connect an extender sling to this. 

This tie in point rapid-link can be fixed in place for the duration of the session, and so can be locked down using a spanner. 

When connecting the rapid-link to your harness, is it best to have the locking collar facing out, so it’s easier to check before you start to climb, or in, so it does not connect with the terrain? That choice is one only you can make.

D-Link

The 10 mm D shaped rapid-link, is a stalwart of caving and rope access, generally used in the same as a climber uses their belay loop. Being rigid, and very strong, this loop is much easier to clip in and out of, but at the cost of not being a closed-loop, like a sewn belay loop.  A D-link can be used as a way to remove a link in your system, with a lanyard attached directly to a D-link for a back-up connector, or for your extender sling, rather than a standard rapid-link. 

Notes

Being made from steel, a little more care is needed when storing, as they can rust, so store them in a dry place, and a little grease is recommended. You will also be able to spot the difference between high-quality rapid-links, namely Peguat ones, and low-quality ones, after long term storage, as the crap ones will be going rusty, while the good ones will not.