5 Basics to Rappel Rope ( Construction, Dimensions, Materials, Dynamics and Care)

Rope is the life blood of  your rappel device. Without line you cannot rappel. Rappel rope is the single most important part of the rig, besides of course the climber. Rope has been around for quite some time. We as a species have been twisting, grouping and pulling on fibers for ages. You may be shocked at how many different types of materials (with flexion) can be made into rope…

The majority of rappel rope that you will find in the marketplace today is constructed, in some way (sheathe, etc)  with nylon. However, you will come to find many special types of ropel that disinclude nylon in material and construction. Since you are putting your life on the line when rappelling, you should really get to know the ins and outs of the types of ropes available today. You must also have a clear understanding of how to maintain your rope once you utilize it. How you treat your rope will determine how durable and reliable it will be during its lifespan…

Tools Mentioned..

 I.D.ModelFeaturesCompare Prices
#1rappel rope bag, rope bag, black diamond rope bag, black diamond rappelBlack Diamond Super Chute Rope Bag°Dual color coded loops

°quick release/attach hook

° Fits 80m of rope/accessories

°Lightweight and Superior Quality. Editors choice in Climbing Mag
Compare Prices
#2descender petzl, descender rappel, descender rappel mechanism, petzl mechanism, petzlPetzl - I'D S, Self-Braking Descender
° Lightweight and dependable

° Can use on wet ropes up to 11mm

° Anti-Error Catch/ Anti Panic Function for an incorrect rig and aggressive pulling

° Multi Functional Handle for better control on the descent

°Ascender handle

°Editors Choice for best Descender in Climbing Mag.
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#3Eight Strand Plaited, Eight Strand Plaited RopeLewmar 8 - Plait° Does not loop onto itself

°Anti-twist with same tensile strength as 3 strand

° Anti-Kink and stiffening due to age
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#4Dynamic RopeEdelrid Python 10.0mm Dynamic Climbing Rope° 33% Dynamic Elongation


° 7 UIAA Approved Falls and 8.9 Kn impact Force

° Zero Sheath slippage

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#5Omnipro, Omnipro Gear, OmniproGear static, Omni RappelOmniProGear OPG ATAR static kernmantle rescue rappelling rope 11mm°Elongation - 2.2% (300lbs - 7.4% (1000lbs)

° Minimum Breaking Strength: 33.3kn

° Highest rated for Static Elongation

° Great for Tactical and Rescue and Certified to UL Specs
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Rope Construction

Pictured: Mantel housing kern

The ropes of old were all constructed from natural fibers, which when stripped to the core, are  a pretty short length. In order to have made a completed rope, it took a significant amount of fibers to ultimately twist them a great amount and manually from end to end. The fibers would be laid together and someone would literally twist them again and again until yarn was formed. .

When this loading was done, fibers would have almost this glue property to where it took significant amount of pressure to unravel them. It would be a near impossibility to slip them apart from each other with just shear muscle. Ever try ripping apart a whole ream of paper stacked on top of one another? Same principal with fiber strand properties. The fibers are positioned along the length of the formed yarn, in order to have one focal breakpoint as opposed to many breakpoints.

In order to keep the yarns from unraveling, yarns are joined with other yarns in an almost clockwise fashion. These grouped yarns are called strands. In manufacturer lingo, this whole process is known as right-laid formation rope making.

Also…

The angle at which the yarn/strands are spiraled actuates the properties of the rope (durability, length elongation, weave strength in splicing and rigidity). The more compact the spirals formed and the bigger the number of helix’s, the more the rope stretches and the weaker it is. the more linear the strands are (straighter) , the greater the durability but the less elastic the rope is. But, you need  some helix formation in the rope in order for the rope to be secure enough to be used. In other words, spirals in the rope are essential for rappel use.

We would advise to go with from hard lay ropes that are too spiraled in construction. This rope is stiff yet flexible. These ropes tend to break in less spots than your standard lay ropes. The less breaking points the safer the rope. Also, stay away from soft lay ropes which will have little to no spiral properties, making them very soft and non elastic, which will be a safety issue as a climber.

Hard lay ropes tend to absorb sudden weight changes while rappelling. The helix’s on a hard lay also do a good job at wicking away any dirt particles and sharp edges better then standard and soft lay lines.

ROPE FIBER, RAPPEL FIBER, ROPE RAPPEL FIBERS

What kind of fibers are used in rope making?

Many fibers are used in the construction of rope making. These include silk, cotton, sisal, jute, flax and manila to name a few. Silk fibers are expensive but would be the choice for quality if it supply and availability weren’t an issue. You will find manila in most rope constructs because of its never ending supply (comes from the Abaca plant which is commercially grown in the Philippines, Costa Rica and Ecuador). Sisal is the second most used followed by hemp. Cotton strands are not as durable as the latter fibers mentioned but you will find some that swear by it.

The problem with natural fibers is that they descontruct overtime due to natural elements (rain wetness especially) and also get worn down easy from human use. When kept new and away from wet conditions, they serve really well but that is not realistic in an outdoor sport. So even though many still use natural fibers in rappel line manufacturing, they would not be our first choice.  Take Manila for example. When you store this kind of rope, it loses .5 to 1.5 % of its durability even when stored in optimal conditions.

Also, natural fibers are able to absorb their own weight while damp which essentially doubles the weight of the entire cord when it is completely submerged. That can weigh heavily on your Rope Bag. Even more, the last thing you want is for this damp rope to freeze up, adding even more weight and becoming unusable. Avoid using a descender on a frozen rope. It will destroy the rope fairly quickly. Manila ropes need only 13-15% of stretch to rip apart because their individual fibers need only 1-4% of stretch to tear.

 

 

So…

Use natural rope only when you are faced with no other option while rappelling. We recommend using synthetic rope for all your rappel pitches. These ropes are also laid ropes and are longer in fiber length than the natural fibers, run the length of the rope and are superior in durability, length elongation, weave strength in splicing and rigidity. The majority of laid rope made specifically from climbing and rappelling will be your Type 6 and 6-6 nylons which are military grade.

What are some disadvantages as far as rappelling with synthetic rope?

Pictured: Splicing and kinking of synthetic after lots of use

Although synthetic is the absolute choice(by far) for rappelling as there are many advantages to using synthetic, there are also few things to keep in mind while using them.

  1. Like natural rope, synthetic rope does have a tendency to kink, since they are of twisted construction. While you rappel, the rope will want to untwist itself, causing kinkage. This happens below the descender mechanism, which are used primarily to keep the rope running straight.  This happens a lot while using dual ropes. To avoid kinks, the lead rappeler below at the next station would do his/her best to keep the lines spread apart. Also the shorter the line, the less potential for kinkage. However, that means more lines will need to be joined together if you are rappelling long distances. Easy does it champ!
  2. Synthetic laid ropes have crazy amounts of elongation which is a good and bad thing. When you are rappelling off a sharp cliff’s edge, make sure to use edge rope protectors so that the elongation properties of the rope don’t reach their max, only to be carved up by a sharp edge, and as a result you plummet to your death! Most synthetic ropes will elongate to about 7 to 13% longer as to the weight of the rappeler. This can cause serious issues too, when trying to abruptly halt close to the end of a distant and speedy rappel. You have a good chance of hitting the ground even though your line isn’t extending down to the floor. 
  3. They are noisy! So if you are trying to be stealthy, especially if you are enlisted and using synthetic rope in your call of duty, you may have to use natural fiber rope instead. Synthetic ropes make this tapping or click noise while pitching a rappel. 

What are some advantages to synthetic rope rappelling?

In most cases, you should always use synthetic rope in your setup one way or another. Here are some advantages to rigging synthetic…

Pictured: Plaited vs Braided Construction

  1. Reliability for being stronger then natural ropes. Made with the intention to use in sports and outdoors.
  2. Forceful and powerful that carry with it, an elastic rubber band property thats come in handy while rappelling. Synthetic ropes are less likely to effect anchor points, can leverage without breaking and can handle sudden weight changes. Some of the better synthetics can elongate over twice its normal length

Pictured: Synthetic rope rappel

Along with twisting yarns, they can also plaited or braided. Eight-strand plaited line was tested to be the better line for rappel purposes vs braided line. Braided and Plaited both show less elasticity than laid rope. They also perform with greater durability  for any diameter and have a lesser propensity to kink or twist out of shape then laid rope. Since these types of ropes are more delicate and more supple then hard lay, they will lose durability with use much faster then hard lay ropes.

With braided or plaited, you will notice the fibers at the surface area of the line, especially when you are dealing with a longer rope. When the surface of the ropes begins to erode, the fibers are exposed to being severed. That is why  it is important to change out your synthetics frequently when they begin to show signs of wear/tear. 

What is the best construction available for rappelling?

Pictured: Rope Construction (minus plaited)

There are those that would refute this, but commonly kernmantel is seen as the most optimal construction for rappel line in this day and age. They are constructed using a core group of fibers encased with a braided sheath. The sheath or mantle has a primary job and that is to house the core fibers or kern for dirt particles and cuts into the core, which in turn gives the rope a longer lifespan.

Kerns may run linear or in a parallel direction while also forming twists and braids. The kern and mantel relationship determines all the ropes characteristics such as stretch, grip, durability, edge strength, knot strength, temperature limitations, lifesan, slippage and many more characteristics. The more compact the braids (kern) are inside the mantle, the result is a shield constructed to help avoid abrasive situations such as rock cutting into the line.

If you are using a line that has free hanging or loose braids, such as when you pick up a double-braided line, the softness coupled with a lack of a abrasive repellent is the product your receive. You also want to make sure that the kern and mantle are made of the same material, otherwise you need to understand each of the materials properties and how elements may affect them.

More on kern and mantle…

KERN, MANTEL

Hypothetically, if your rope uses polyester mantel on top of a nylon kern (which many ropes do) your rope does a great job at repelling UV rays. flip them around (nylon mantel and poly kern) and your line is made to be extremely durable while being buoyant (float over water). But , since the materials have different flexibility characteristics, you may have a rope that can’t resist sharp cuts to it as well as when you have a rope that has a mantel and kern with the same properties.

Let’s say you have kern made of steel wire, and your mantel is made of nylon. Sure, it will be hard to cut through steel wire threads and will do well with high temperatures (due to friction), but the flexibility of the rope may suffer. Be really careful when you utilize a rope like this. Also, remember nylon will not do as well with higher temperatures. Roughed up nylon causes the descenders to lock up, which will cause issues.

Static vs Dynamic kernmantle…

With kernmantle you have two different kinds of classifications: Static and Dynamic. When you rappel with Static rope you are using a line that has kerns running parallel which are housed with a compact mantel. You will typically have your Statics at an elastic measure of 2% of weight of up to 200 lbs and will have breaking point loads of 18-22%. So essentially, the Statics hardly stretch. You would use:

Statics

  1. When you are trying to get safely over a challenging ledge.
  2. When your rappel pitch is very long.
  3. When you are looking to  transfer heavy loads (such as your gear) up or down the rappel. 

 

If you have trouble with jammed ropes, then Statics may help with this. They have a propensity to avoid kinks in the threads. Dynamics have kerns that run in braided fashion. You would use:

Dynamics…

  • When utilized as belay devices for mountain terrain and rescue team work. They are built to withstand heavy amounts of weight such as when a rappeller is falling so to avoid any further injury. 
  • Rappelling shorter pitches

Pictured: Rappeler using dynamic rope belay setup to reach a 60 ft waterfall pitch

These very much have a rubber band effect to them to take on a great amount of stress. They are laid ropes in a sense that they have breaking elongations of over 35% of their normal state. When measuring at bodyweight (174-180lbs) they flex to about 3-9% depending on product itself.  Dynamics make excellent rappel line, especially when on shorter distance pitches. Dynamics work to resist jerky, rough rappels, which you want to avoid so that the anchors don’t break. However, be careful when going over an edge when using Dynamics since you will have to brace yourself for any excess elongation.

Remember: Kerns may be either braided or twisted. This coupled with fiber girth , cross-sectional form and structural materials are what ultimately actuates the ropes durability and flexibility characteristics. 

Conclusion

When the plan is to pitch a distant rappel, go with Static ropes. For shorter distances, you may choose to belay with a Dynamic rope. The less flexion the better on distant rappels. If you set out to go ascending a climb and descending a rappel, use Dynamics. Reason being is that if you are climbing and happen to fall, Static ropes would not be forgiving in the fall and you may break bones in your body because of the excess resistance in Static ropes. Add to that, if you are climbing and fall using static, the pressure forces put on the anchors will not be ideal and may come apart.

With kernmantle, the biggest issue is when the mantel is uncovered, slipping off the kern. You will lose strength in the line and will also lose control. When this happens, replace the line with new line on your next rappel. The slipping doesn’t happen on one or two rappels. It may take years for the mantel to start slipping. When it does, recognize it and replace the rope if it is not salvageable. The better your descender mechanism is, the less slippage will occur in the long run.

In rope construction, the more continuous the rope fibers are (continuous helix) the better the rope will be. The less patch splices the better. The problem is that plenty of ropes are made this way, whether the fibers are knotted together or overlapping one another. These manufactures make rope this way because its way less expensive too. They get away with it because the overall durability of a spliced rope will be at par with a line that is not spliced. However, they will not last as long (the mantles will eventually slip faster) as the ropes with only continuously fibers for the length of the rope. When you are looking for the right rope to purchase, look for rope that have zero amounts of splicing if you can.

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