Last year Petzl released the RAD (Rescue And Decent) system which is basically a lightweight rope kit. The idea is that skiers and maountaineers can take it with them into mountains to deal potential issues such as rappelling cliff bands, undertaking crevasse or cliff rescue and for roping up when crossing glaciers. While light-weight kits of this nature have been available to Guides for some time Petzl has made the RAD system available to everyone. This is great as it’s more likely that people will actually take the emergency equipment with them into the mountains if it’s light… as long as it works well! So, how light-weight is the RAD system? When does it work well, when doesn’t it? To evaluate the RAD system we did what we do best: abused it!
So let’s start with what’s in the RAD system:
- RAD Line (basically a 30m* x 6mm static cord)
- Micro Traxion (a low-friction, simple and effective pulley/progress capture device)
- Tibloc (super simple rope grab)
- 3 x Attache 3D Carabiners (I love these things)
- 120cm dyneema sling
- A great stuff sac w. ice screw sleeve
* Now also available in 60m
While each of these items are available on their own the kit puts them into a convenient package that, when combined with a harness, creates a good basic light-weight rope kit. That being said, there are a few extra items that could also be considered depending on the intended use, expected terrain, etc. but i’ll talk about that later. Lets focus on the RAD line first as it’s new and central to this kit.
The RAD line is a 6mm static cord that is made from high modulus polyethylene (also knows as Spectra® or Dyneema®), aramid (a heat resistant synthetic fiber) and polypropylene. When compared to 8mm dynamic half ropes which are often used for glacier travel this represents a weight savings of almost 50% (22g/m versus 37-42g/m for 8mm+/- dynamic half ropes), huge right! Given it’s small diameter and light weight the RAD line still has a relatively high breaking strength of 12kN (earlier documentation stated 8kN but this was in reference to the testing requirments, the actual strength is 12). It is of note that this 12kN strength is dropped to about 6kN as soon as a knot is tied in the line, a force that could be achieved by shock loading the system if not careful given the static nature of the RAD line.
When we started playing with the RAD system the first thing that we noticed is that there’s no middle mark on the RAD line, not surprising given that high modulus polyethylene and aramid doesn’t dye well. However, this can be a bit of pain in the ass when rappelling. Speaking of rappelling on the RAD line, we tried a Reverso 4 and a few other tube style belay devices as well as an Italian Hitch (Munter). This testing was quite eye-opening. We found that there’s not nearly enough friction to use the Reverso 4 or other tube style belay device safely with the typical rappel set-up. However, by doubling up on the Attache 3D carabiners at the Reverso 4 the friction is increased to where things were much more reasonable. Carabiners with a round cross-section like the Hera didn’t increase the friction nearly as much. The Italian Hitch worked very well, using just a single Attache 3D carabiner and two strands of line. The takeaway here is that the RAD system requires very specific tools to work properly and substitutions should be carefully thought through. Also, because the RAD line is quite thin it can be hard to hang onto when rappelling so a back-up is a good idea.
It’s hard to compare static and dynamic ropes (which are often used in glacier travel) as dynamic ropes stretch to absorb energy and are not rated by breaking strength. So let’s look at the pro’s and con’s of the static RAD line versus a dynamic half rope instead. When rappelling or undertaking a rescue a static line is great as there’s very little stretch to pull out the rope making it much more efficient. On the down side the force of a fall is not reduced by rope stretch resulting in higher forces in a fall. Some research that Petzl has done on this topic indicates that there is a slightly better chance of arresting a crevasse fall with a static rope as the load is more predictable. However falls on rock or during a rescue could be catastrophic on a static rope. Anyway, what I’m saying is that there are benefits to the static RAD line but that there are also trade-offs to consider.
The RAD kit (the hardware anyway, regardless of the rope used) makes rope ascending incredibly easy and quick. Especially when compared to self raising or double prussic systems. The ability to put the Micro Traxion on a loaded rope (ie. when you’re dangling on at the end of the line) makes it quick and painless to move into an ascension mode. Once climbing the low-friction system makes climbing easy, just make sure you set the Tibloc each step to avoid fraying the rope.
Petzl has created a great basic rescue kit with the RAD system. However, as mentioned before, it’s not necessarily a complete set-up depending on what you’re doing and so should be looked at as great place to start from when building a kit for a given trip. A few of the items that could also be considered depending on your application, how many people are in the party, etc. include:
- Ice screw or two (if there’s not a lot of snow this may be the only way to build an anchor, the Petzl Laser Speed Light screws are a great option as they are very lightweight)
- 5mm tech cord prussic material or a Sterling Hollow Block (a back-up for rappelling, a personal safety point for crevasse rescue, etc.)
- Pulley (not a cheap pulley, if you’re going to pack one around make it a good one, the Petzl Mini Prusik Minding Pulley or the Rock Exotica P21 Mini Pulley are both great options. Good pulleys can really reduce the amount of friction in a rescue system which can be beneficial if there’s a big weight difference between two people in a party. Prussic minding pulley’s also make more forgiving progress capture devices in rescue scienarios.)
- 2 x non-locking carabiners (depending on the situation, a couple of light-weight carabiners can be useful and they don’t weigh much. One of my personal favorites is the Camp Nano 22)
- An extra 120cm or 240cm dyneema sling (just one sling can be a bit limiting, ie. if the sling is used in the anchor then it cannot be used to ascend the rope or increase advantage).
- A dynamic rope (if the trip involves some climbing the RAD line can be left at home or, even better, stashed in the pack of the last person in the group. The great thing with this kit is that all the equipment will work with either a climbing/glacier rope or the RAD line making it very versatile.)
One thing that tickled the back of my mind when testing out the RAD system for improvised companion rescue is that it’s a very streamlined system with little room for error. Any significant shock load, such as could occur if the lip of the crevasse collapses mid-rescue on a single line raise system, could be catastrophic. Now I don’t mean to say that this kit is dangerous, only that it has limitations. As it says on the bag “Expert Use Only”, if you plan to use the system it’s worth taking the time to practice with it.
Speaking of training, it should also be noted that it takes training and practice to become safe and efficient at glacier travel, crevasse rescue, rope decent and ascent, etc. Purchasing this kit and/or other equipment is a good starting point but without the expertise to use it, not much of a benefit. If you’re new to these activities or want to learn more I can help out, just shoot me an email.
Pros: This kit is very light, simple, expandable and efficient.
Cons: No middle mark on the RAD line, progress capture device (MicroTraxion) is not load limiting.
Overall: If you’re looking for a versatile light-weight rope rescue kit this thing is great! However, be aware of the limitations and you will likely want to customize the kit with a bit more gear depending on the trip or expected use.
Petzl supplied a sample of the RAD kit to use and abuse but of course this did not influence our review in any way.