When it comes to what kind of rope to use for rappelling, you may have noticed static ropes and dynamic rope. I had a dynamic rope for climbing and wanted to know if I could use it for rappelling so I did some research.
You can safely rappel with a dynamic rope. Many climbers rappel off anchors at the top of the cliffside using dynamic ropes. The dynamic rope is ideal for lead climbing so by rappelling with it, they only have to carry one rope instead of a rope for rappelling and a rope for climbing. However, if the sole use of the rope is to rappel and climbing is not involved, then a static rope is more ideal.
The difference between static and dynamic rope is the amount of stretch or elongation of the rope. The activity you are doing will dictate the type of rope you will need. For example, if you are climbing and falling, you will want the rope to stretch slightly to help cushion the fall. When it comes to rappelling, the rope needs to remain tight so the descent is as smooth and easy as possible both for the person rappelling and for the gear being used. Because everything needs to be as tight as possible, you don’t want any give or stretching of the rope, which is why static rope is ideal for rappelling.
Every time the rope stretches, it can increase the amount of rubbing the rope does over rock edges. This rubbing can wear the rope down faster. Additionally, the static rope is typically less expensive than a dynamic rope.
If you do both climbing and rappelling often, then you may be wondering if you should just get one rope – a dynamic rope instead. If you can afford it, I’d recommend getting a separate rope for rappelling. Below are considerations when comparing the two.
Static Rope Tends to Be Less Expensive Than Dynamic Rope
Static ropes usually last longer and are less expensive than dynamic ropes. Depending on the length of rope that you need, the price can vary. Additionally, the brand, diameter, and dry coating can affect the price. Here is a general range that you can expect based on length and type of rope.
|Length||Static Rope||Dynamic Rope|
Static Rope Tends To Last Longer Than Dynamic Rope
When rappelling with a rope, the durability will not only affect how long the rope will last but it can also affect your safety. Dynamic and static ropes are both very durable, however, the wear on a dynamic rope is typically higher when it comes to rappelling versus static rope.
The reason for this is because if the rope is running off the edge of a rockface, as the stretches and constricts, as dynamic rope does, it rubs against the rockface. In comparison, the static rope, because it stays tight and isn’t stretching or constricting, doesn’t tend to rub against the rock as much.
Additionally, the belay device that you use while rappelling may affect how much wear the rope will go through to slow down and speed up during your descent. For example, many ATC belay devices, which are used by some climbers, use metallic grooves to add additional friction and control for the person using the device.
The difference between this and belay devices like Figure 8, is that the metallic grooves tend to place more pressure on certain parts of the rope whereas Figure 8 devices tend to have a more even layer of friction. The uneven friction across the face of the rope may make it wear out faster.
Static Rope is Less Multi-Functional Than Dynamic Rope
Static rope is specifically designed and tested for activities such as caving, canyoneering, rescue, or hauling gear where you don’t want a stretch in the rope. For example, you don’t want rope attached to an injured climber to bounce while being moved due to the stretch of the rope. However, the static rope is not ideal for climbing since they do not flex when a climber falls and aren’t tested for the impact on a rope that climbing has.
Dynamic rope, though it isn’t ideal for rescue, can be used for rappelling and climbing so it could be considered more multi-functional. The key takeaway here is that if you want to use the rope for both climbing and rappelling, then it may be a good idea to purchase a dynamic rope until you have the resources to get a second rope that can be designated specifically for rappelling. However, if you don’t plan on climbing, then it is a good idea to invest in a static rope that will give you the most rappels possible on a tight line.
Standard Testing and Ratings
When it comes to the safety of a rope there are standard testings and ratings that separate a safe rope from a rope that should be left unpurchased by rappellers or climbers. Additionally, there are different standards for dynamic climbing rope and static rope.
One of the biggest differences is the impact force which indicates how much force would be put on the person attached to the rope and the anchor system if they were to fall. In the case of a dynamic rope, this impact force is related to how much force would be put on the climber, the belayer, and the anchor system if the climber were to fall.
For a dynamic rope to be certified as safe according to UIAA, the international climbing and mountaineering federation and a world standard for safety equipment, the maximum impact force for a dynamic rope is 12kn for Single Rope and 8kn for Double Rope.
That means, when using a double rope, for example, the maximum force the rope can put on the climber if they fall is 8kn. This rating is also based on a Factor 2 Fall, which is the highest impact force we can produce while climbing.
Static rope, on the other hand, can be rated up to 24kn if someone were to fall on the static rope. That is three times the impact force of a dynamic rope and could lead to serious injuries. That being said, you shouldn’t be falling on a static rope, to begin with as you should always be below the anchor. This means that as long as you are rappelling safely, you won’t incur the impact force.
Standard Falls Before Breaking
Another major difference when it comes to standardized testing and ratings is how many falls a rope can handle at a fall factor of 1.7kn, which is slightly below the maximum force possible to incur, before breaking.
For a dynamic rope, a single rope can take five falls before failing. However, there are multi-fall ropes that are rated to nine falls.
Static rope, however, is not rated for falls and is not required to undergo fall tests. Fall factors are 0 when there is no additional rope in the system and you are below the anchor. Therefore, there is no need for fall tests when considering how long the rope will last.