Ice climbing, ropes and single vs. half
Tuesday, January 3rd, 2012 11:34 by juho Print Print this page

There’s been plenty of debate about the rope systems in ice climbing, weather to use single or half ropes in particularly. Some folks swear to the half ropes, whereas other insist that single ropes are better due to actually lower impact forces. So here’s my take on the topic. To orientate my view, I’m writing almost entirely from the perspective of multi-pitch ice climbing on pure waterfall ice. While I know that there are climbers with more experience under their belt, I hope the insights below are useful for fellow climbers, at least while figuring out their stand on the topic. I’ll dive into different rope systems once I’ve taken the beginners through the basic principles, if you’re an experienced climber you might want to skip the basic principles part. :-)

Picture above: The ropes I’m currently using.

Basic principles

Ideally you would like to select a rope that’s light, long, has low impact force, as well as excellent handling and is durable. Unfortunately these characteristics are, mildly put, somewhat opposing. So lets put these in order.

  1. Weight is an issue, approaches are usually long and heavier ropes also adds up while climbing. The weight difference between light and heavy ropes might be several kilos. So in my opinion that’s the number one.
  2. Low impact force makes the climbing safer and anchors less likely to fail. Again something that’s really, really important, that’s my number two criteria.
  3. Handling is again something that makes a difference. However on ice it’s not that much about the friction or ease of paying out the rope in simple sense. Most ice climbers are already experienced and confident belayers. Dry treatment has lot bigger impact here, as icy ropes are really, really difficult to handle – you should get the best dry treatment available. In trips that last multiple days, you can’t dry the ropes and the ice adds up. It also adds up in terms of weight. In short dry treatment is well worth all the money put into it.
  4. Far after these three criteria comes the durability. Yes, it’s important, but not nearly as much as in rock climbing. In winter conditions ropes tend to wear a lot less than on rock because there’s less dirt and mud as well as friction. In ice climbing lead falls are also very, very rare, at least they should be. They’re such a dangerous affair that people should avoid them at all cost; if you fall, the rope that needs to be discarded is least of your worries. I’ve taken one lead fall and I’m not planning to take another one. Furthermore if ice axe or crampon nicks the rope, even thicker sheath is unlikely to protect the rope. Besides you can always cut the meter or two (the area where ice axe / crampon is likely ti nick) off from the rope without serious losses. So the durability is the least important factor, at least for me.

So after these rope characteristics you’re down to two choices; The length and type, i.e. single vs. half ropes. While type question is somewhat complicated issue and I’ll dive into the topic shortly, the length is much more straight forward. For multi-pitch ice climbs that typically have several snow sections, 60 or 70 meters is in my opinion a good length. Longer rope makes the rappelling faster.

Single vs. half ropes

Generally speaking half ropes offer several advantages over single ropes. While climbing they allow lower rope drag because one can alternate clipping according to route so that ropes go straighter line. Half ropes also offer “naturally” longer rappelling distances due to two strands. In single rope system one needs to compensate that with a tag line. Further more half ropes offer redundancy in case of a fall or when rope gets damaged for some reason. Yet despite the two strands these two rope systems, i.e. half ropes vs. single with tag line, weigh about the same (single + tag = 75-100g/m vs. 2*half = 76-84g/m). In terms of weigh the only positive side with the single ropes is the fact that leader doesn’t have to carry the tag line. However in my opinion this advantage is diminished by higher rope drag, even on steep ice where you usually get to climb relatively straight lines. So based on above the only matter left to discuss is the impact force.

There’s been plenty of discussion about the impact forces. While on the surface half ropes seem to have lover impact forces, they’re actually measured with different standards. Tests with singles are being done by using 80kg weight, whereas half ropes are measured only with 55kg. For this reason some people claim that half ropes actually generate higher impact forces to the protection than single ropes. As there’s no comprehensive data on how half ropes perform as single ropes, one way to look into topic is to take a look at the ropes that conform both standards and then compare the results to ones that conform just one standard. Lets take a look at the specifications of multiple standards ropes first (the data is from, a climbing gear database that among other things has the specifications of several hundred ropes).

Rope Diameter Weight Single Half
Millet Absolute Pro 9.0mm 54g/m 7.8kN 5.9kN
Beal Joker* 9.1mm 53g/m 8.2kN 6.0kN
Edelweiss Performance 9.2mm 53g/m 8.2kN 6.0kN
Bluwater Ropes Dominator 9.4mm 55g/m 8.29kN 6.61kN
Bluewater Ropes Hyalite 9.4mm 55g/m 8.29kN 6.61kN
Edelrid Sports Swift 8.9mm 52g/m 8.8kN 6.7kN
Mammut Serenity 8.9mm 52g/m 9.5kN 7.1kN

Table above: Multipe standards ropes that conform both UIAA single and half specifications

So while this is manufacturer’s advertized specifications and definitely involve some creative rounding etc. there’s at least a one conclusion that can be made. Lower single impact force leads to lower half impact force and other way around. Based on above one could expect that a half rope that has lower impact force than the ones above, would also have lower impact force when measured as a single. Also the impact force ratio of single to half seems to be somewhere between 0.7-0.8. So lets take a look at some light half ropes, low impact force single ropes and compare them to the above multiple standards ropes then. For half ropes, I’ve calculated the single impact force values using the ratio above and shown in parenthesis.

Rope Diameter Weight Single Half
Monster Ropes 9.2 9.2mm 53g/m 6.8kN n/a
Beal Ice Line 8.1mm 42g/m (6.1-7.0kN) 4.9kN
Tendon Master 9.4 9.4mm 58g/m 7.0kN n/a
DMM Climbing Prodigy 10.0mm 64g/m 7.1kN n/a
DMM Climbing Statement 10.0mm 66g/m 7.1kN n/a
Petzl Dragonfly 8.2mm 42g/m (6.3-7.2kN) 5.07kN
Tendon Ambition 10.0 10.0mm 65g/m 7.2kN n/a
Petzl Zephyr 10.3mm 67g/m 7.28kN n/a
Beal Booster III* 9.7mm 63g/m 7.3kN n/a
Beal Tiger 10.0mm 63g/m 7.3kN n/a
Roca Migu 8 7.9mm 41g/m (6.5-7.4kN) 5.2kN
Edelweiss Oxygen 8.2mm 42g/m (6.5-7.4kN) 5.2kN
C.A.M.P. Plekton 8.2mm 42g/m (6.5-7.4kN) 5.2kN
Beal Apollo II* 11.0mm 75g/m 7.7kN n/a
Millet Absolute Pro 9.0mm 54g/m 7.8kN 5.9kN
Tendon Ambition 7.9 7.9mm 40g/m (7.0-8.0kN) 5.6kN
Sterling Rope Fusion Photon 7.8mm 41g/m (7.0-8.0kN) 5.6kN
Tendon Master 7.8 7.8mm 38g/m (7.1-8.1kN) 5.7kN
Metolius Monster Ropes 7.8 7.8mm 38g/m (7.1-8.1kN) 5.7kN
Singing Rock Gemini 7.9mm 39g/m (7.1-8.1kN) 5.7kN
Beal Joker* 9.1mm 53g/m 8.2kN 6.0kN
Edelweiss Performance 9.2mm 53g/m 8.2kN 6.0kN
Bluewater Ropes Dominator 9.4mm 55g/m 8.29kN 6.61kN
Bluewater Ropes Hyalite 9.4mm 55g/m 8.29kN 6.61kN
Millet Alpin Lite 7.9mm 41g/m (7.3-8.3kN) 5.8kN
Mammut Phoenix 8.0mm 41g/m (7.5-8.6kN) 6.0kN
Sterling Ropes Marathon Pro* 10.1mm 63g/m 8.6kN n/a
Sterling Ropes Marathon Mega* 11.0mm 79g/m 8.7kN n/a
Edelrid Sports Swift 8.9mm 52g/m 8.8kN 6.7kN
Edelrid Sports Apus 7.8mm 42g/m (8.4-9.6kN) 6.7kN
Mammut Serenity 8.9mm 52g/m 9.5kN 7.1kN

Table above: Light half ropes, low impact force single ropes and ropes that conform the both UIAA standard compared against each other.

So following the line of reasoning of the first table, it would seem that at least quite a few half ropes should offer comparable impact forces when tested as a single. Furthermore while most of the multiple standards ropes are light, their impact forces are left behind most light half ropes.

The final thing to consider is how the lead fall differs from each other between the two systems. While a fall with a single rope is rather straight forward process, i.e. you always fall to the single strand, the issue is at least in theory somewhat complicated with the half ropes. With half ropes the number of strands that actively work while stopping the fall depends on distance to last piece of protection and rope stretch. In most cases half ropes act just like single ropes, i.e. one strand takes the wast majority of the force. In case of half ropes the rope stretch typically falls between 25% and 40%. If the average screw distance is about 6 meters, this means that you have to have at least two screws and 15 meters of rope out until second strand can even theoretically come into play. In other words you’re already well above the UIAA test case fall factors, i.e. the impact forces are a lot smaller. For this reason the way two strands interact doesn’t have relevance in normal climbing. However when leaving from the stance, where both strands are actually clipped through the anchor the issue is a bit different. There both strands work together and impact forces are a lot higher, worse still the fall factor is the worst possible. It seems that half ropes demonstrate impact forces in the range of 8-10kN in twin configuration.

Based on this, together with the other half ropes related benefits, at least my opinion is clear, half ropes is the way to go. However with half ropes it’s even more important to make sure you don’t fall against your stance. There’s a serious worst case scenario involved. This leaves also a difficult choice, weather to go with the lowest impact force half (Beal Ice Line) or the lightest one (Tendon Master 7.8 / Metolius Monster Ropes 7.8, basically a same rope manufactured by Lanex)? While 1kN difference in impact forces doesn’t feel dramatic it is probably larger in worst case twin configuration. On the other hand 500g / 10% difference (two strands, 70m long, 38g/m vs. 42g/m) doesn’t feel huge, but still considerable. Also the Tendon’s nano dry treatment is said to be great (though I don’t have much first hand experience, climbed just once with such rope)… …Right now Beal Ice Line feels a better bet. Funny enough I’ve been contemplating between these two ropes for some time now. :-)

Oh, one final note; famous Will Gadd has an interesting article about the impact forces and comparing single ropes against halfs. They also actually did some real world tests, so a bit more scientific than my approximation approach. I have noted the ropes in the table that Will talked about with asterisk (*), with one exception for which I couldn’t find the specifications. From Will’s article it comes loud and clear that there’s plenty of variation as some difference compared to published figures. Despite these uncertainties, I’m still for half ropes for multi-pitch waterfall ice climbing.

My current ropes

Finally a few words of my current ropes and their uses.

Picture above: Rope endings with markings, I had to cut Joker due some nicks.

  1. Edelweiss Sharp 8.5 – They’ve served me well for quite a few years. They’re still the ones I use when climbing multiple pitches. They’re a bit heavy and bulky, but the quality, especially from the durability perspective has been great. They provide fairly good handling characteristics, and dry treatment worked well; There’s still some left.
  2. Beal Joker – It was originally my “soft landing” plan to half ropes. I haven’t used Joker too much, mostly while top roping either indoors or while ice climbing on short falls. Still Joker is a good quality rope and even though some people consider it slipery, especially when new, I like the “slippery feeling” of it – it’s easy to feed and rappel with. Also the dry treatment is good.
  3. Beal Rando – My short and light twin rope for glacier travels and mountaineering routes that do not require serious climbing with belay. It again a good quality, but most importantly in a very light, only 36g/m package.

The web-stores that sell these things:

  1. Metolius Monster Ropes 9.2 – BackcountryMoosejaw
  2. Beal Ice Line – BackcountryBarrabes, Telemark-Pyrenees
  3. Tendon Master 9.4 –
  4. DMM Climbing Prodigy –  ?
  5. DMM Climbing Statement – Needle Sports
  6. Petzl Dragonfly – BackcountryMoosejaw
  7. Tendon Ambition 10.0 –
  8. Petzl Zephyr – US Outdoor Store
  9. Beal Booster III – BackcountryBarrabes, Telemark-Pyrenees,, Moosejaw
  10. Beal Tiger – Barrabes, Telemark-PyreneesMoosejaw
  11. Roca Migú 8 – ?
  12. Edelweiss Oxygen – Backcountry
  13. C.A.M.P. Plekton –  ?
  14. Tendon Ambition 7.9 –
  15. Sterling Rope Fusion Photon – Moosejaw
  16. Tendon Master 7.8 –
  17. Metolius Monster Ropes 7.8 – Moosejaw
  18. Singing Rock Gemini – Barrabes
  19. Millet Alpin Lite – BackcountryTelemark-Pyrenees
  20. Millet Absolute Pro- BackcountryTelemark-Pyrenees
  21. Mammut Phoenix – Backcountry, Needle Sports,, Moosejaw
  22. Beal Joker – BackcountryTelemark-Pyrenees,, Moosejaw
  23. Edelweiss Performance –
  24. Bluewater Ropes Dominator –
  25. Bluewater Ropes Hyalite – ?
  26. Edelrid Ropes Apus – Shelby
  27. Edelrid Ropes Swift – Barrabes, Telemark-Pyrenees
  28. Mammut Serenity – REINeedle Sports, Telemark-Pyrenees,, US Outdoor Store
  29. Beal Rando – BackcountryBarrabes, Telemark-Pyrenees, Varuste.netShelby

A few more images of my ropes:


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4 Responses to “ Ice climbing, ropes and single vs. half ”

  1. avatar Toby

    I got the half rope ratings for the Serenity and Swift from their respective makers – they are in the table here:

    I haven’t weighed the ropes I reviewed but perhaps should. Another test for a UK magazine found that actual weights bear very little similarity to manufacturers stated weights.

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  2. avatar Juho

    Thanks, will add those to my article as well. About the weights… Agree 100%, noticed it several times and been wondering why it is like that. Heard some rumors that it would be related someway to the way they’re measured. Don’t know for sure. If you have better knowledge, it would be appreciated. :-)

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  3. avatar Matti JJ Latvala

    Great article, by far the best I have seen!

    Makes me to consider halfs, because rappelling down 2 ropes enables a pull-down with twice as much distance rappelled. Abandoned anchor gear is expensive!

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  4. avatar Juho

    Thanks Matti, it’s great to get positive feedback. :-) About the halfs … I truly believe in them especially on ice. On rock I’m not yet so sure, because the fact that durability seems to be a bigger issue … this being said, it seems that light single ropes, as Beal Joker aren’t very durable either (despite being extremely good rope, on rock you’ll whack it in no time – trust me, I know).

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