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Half ropes as singles


Original Post
Lone Ranger · · Mumbai Suburban · Joined Jul 2015 · Points: 1,589

This is a query from the perspective of a climber who weighs 52kgs (about 120 pounds including sport climbing gear/attire). A half rope such as Mammut Phoenix is tested for 9-10 UIAA falls as a half (i.e. FF 1.77 falls on a 55kg mass). Mammut Serenity is rated for 5-6 UIAA falls as a single (i.e. FF 1.77 with an 80 kg mass). So I am thinking, purely by breaking probability, I am not any less safe using a half, than an 80+ kg climber using a single? I am just not convinced with the manufacturer warning that "half should NEVER be used singly", because I feel they don't apply to my context.

I know, the fact that they tested some number of falls and weights does not translate into the same number of falls guaranteed in the real world; the tests simply give an estimate of overall strength of a brand new rope (ageing can affect ropes variously, and I reckon a rope with a good percentage of sheath will age better). I also know breaking isn't the most significant factor; ropes cut over edges, for which a hardy half like Genesis can be safer than a skinny single like Serenity with low sheath proportion.

The reason I am asking is, I am considering switching to half ropes for simul-climbing sport slab routes in my area, they don't have any edges at all and I intend to climb only routes where I have negligible chance of fall. My partner for this is way stronger than me and just won't fall on these routes (anyway I don't want feedback on simul-climbing); as the weaker climber I plan to be on lead all the time, and this rope will be exclusively for simul-ling. The 300 grams of extra mass of a 30m triple such as Serenity over Phoenix is significant for me. In fact, the drag/weight I save may actually reduce my already small likelihood of falling, so it may be safer overall.

Please let me know if I am missing something; want to run it past a good critique before I attempt to test these in practice, if at all.

Thanks,
TT

Lone Ranger · · Mumbai Suburban · Joined Jul 2015 · Points: 1,589

Mammut Genesis half rope: UIAA falls (single rope 55 kg) 12–13! That is more than twice the number of Serenity's falls on 80kg.

I am wondering if people who weigh significantly more than 80kgs, consider their body weight at all in choosing their systems, or is a single rope considered adequate?

Given the wide range of normal human body sizes (I have at least 2 male and 2 female climbing partners that weigh 50kg and 45 kgs respectively, and I have a good climber friend of mine who tips 100+ kgs), I feel  systems should be discussed with reference to actual body weights and not absolutes as in "half ropes" and "single" ropes...One man's half can be another's full?

Matt Himmelstein · · Orange, California · Joined Jun 2014 · Points: 167

Can and should are two different things.  Can you use a half as a single, sure.  Don't take a high FF fall and you should be fine.  After all, if you climb on half ropes and fall before the second clip, you are only on one strand anyway.  But should you do it is another matter.  They are not designed to be single ropes.  If they were, they would be triple rated.

Noah R · · Burlington, VT · Joined Nov 2018 · Points: 0
Lone Ranger wrote: One man's half can be another's full?
Lol
Kevin Mcbride · · Canmore AB · Joined Jan 2017 · Points: 423

Well that was 6 paragraphs of unadulterated nonsense. The big risk is the stretch from a half rope, you will fall much further, which can result in you smacking into ledges or just decking. If you think that your weight exempts you from rope ratings then you need take all sorts of courses.

Jared Casper · · St. George, UT · Joined Feb 2006 · Points: 10
Kevin Mcbride wrote: Well that was 6 paragraphs of unadulterated nonsense. The big risk is the stretch from a half rope, you will fall much further, which can result in you smacking into ledges or just decking. If you think that your weight exempts you from rope ratings then you need take all sorts of courses.

Mammut Serenity (single rope) dynamic elongation: 31% * 30m = 9.3m.  Mammut Genesis (half rope) dynamic elongation: 32% * 30m = 9.6m. Yup, that extra <30cm of stretch is going to do you in.

"Single" and "half" ropes are just what falls the ropes take before failing, not some mystical designation decreed by the gods.  I don't have enough experience with half ropes to have a strong opinion on the original question, but basic math and logic points to it at the least not being "unadulterated nonsense".  

Cole Metzger · · Unknown Hometown · Joined Jan 2019 · Points: 0

The short answer is that your life is worth more then an extra $50 savings. Just get a single rope.  Plus the medical bills will most likely cripple you more then a trusty 9.8 rope.

Jared Chrysostom · · Charleston, SC · Joined Oct 2017 · Points: 5
Jared Casper wrote:

Mammut Serenity (single rope) dynamic elongation: 31% * 30m = 9.3m.  Mammut Genesis (half rope) dynamic elongation: 32% * 30m = 9.6m. Yup, that extra <30cm of stretch is going to do you in.

"Single" and "half" ropes are just what falls the ropes take before failing, not some mystical designation decreed by the gods.  I don't have enough experience with half ropes to have a strong opinion on the original question, but basic math and logic points to it at the least not being "unadulterated nonsense".  

Is the dynamic elongation measured with the same mass / fall?

NegativeK · · Nevada · Joined Jul 2016 · Points: 40
Cole Metzger wrote: The short answer is that your life is worth more then an extra $50 savings. Just get a single rope.  Plus the medical bills will most likely cripple you more then a trusty 9.8 rope.

The "is your life worth more than $X" argument is reductionist and doesn't actually make a point.

Jared Casper · · St. George, UT · Joined Feb 2006 · Points: 10
Jared Chrysostom wrote:

Is the dynamic elongation measured with the same mass / fall?

That's a good question I don't know the answer, but here OPs point stands... lets assume the dynamic elongation for single is measured with an 80kg mass and with a 50kg for a half.  Why is that single with an 80kg climber safer than the half with a 50kg climber?  If an 80kg climber is okay with the 31% the single provides, why can't a 50kg climber be okay with the 32% the half provides. In any case the argument that a half is more dangerous than a single because a half is going to stretch more doesn't hold.

The point is just blindly saying "single" ropes are safer than "half" ropes just because they are designated as "single" ropes is short sighted and naive.  With an understanding of what those ratings mean and taking into account a specific scenario it entirely possible a half rope is a safer/better choice.  The OP laid out some convincing arguments why a specific half rope might be safer/better for his scenario than a specific single, and this thread is a full of people saying that obviously a single is safer than a half solely because it is designated a "single" without providing any reasons or arguments why.
John Clark · · San Francisco · Joined Mar 2016 · Points: 422

Is the OP simuling with any kind of progress capture or are they accepting the additional fall length of simuling without proper belay?

Todd the Tangler · · Golden, CO · Joined May 2014 · Points: 50

 I've climbed on single half-ropes a handful of times. Sometimes for easy moderate romps, and sometimes because I was in a group and we were short on ropes.

Basically the big thing to consider (in my view) is what belay device you're using. I caught a whip with a regular ATC once and was scared to death I was going to drop my friend. Edelrid makes some sweet super-skinny rope belay devices that are worth the investment if you're going to climb on a single half regularly.

Curt Haire · · leavenworth, wa · Joined Jun 2011 · Points: 1

I routinely use a half-rope for alpine climbs on less-than-vertical terrain where the impact of a fall will be low because the falling body will be sliding or bouncing.  For passages with more severe exposure, I simply fold the rope and use two strands for the belay.  But if you're buying a rope, you can avoid the issue altogether by purchasing a skinny triple-rated rope -- likely the best solution.

Lone Ranger · · Mumbai Suburban · Joined Jul 2015 · Points: 1,589
Curt Haire wrote: I routinely use a half-rope for alpine climbs on less-than-vertical terrain where the impact of a fall will be low because the falling body will be sliding or bouncing.  For passages with more severe exposure, I simply fold the rope and use two strands for the belay.  But if you're buying a rope, you can avoid the issue altogether by purchasing a skinny triple-rated rope -- likely the best solution.

Precisely what I was thinking: these are 1000 foot almost uniform slabs/domes that I climb, where the "fall" is really a tumble and the body will absorb considerable energy before the rope is loaded. One odd steep sections of bolts length, I can use two strands. High FF falls aren't possible during simul-climbing with 2-3 bolts between us, and I don't expect to fall (in 10 years of climbing, I have never taken a lead fall on multi-pitches, and I will be even more conservative on routes that I choose to simul). In all cases, if I take a fall on this rope I will retire it; is is a confidence rope as far as I am concerned. The major reason against skinny triples is, they seem to have very low sheath proportion and the constant dragging over granite may wear them out, so I am not sure they are necessarily better (for me, given my weight) than a hardy half.

Lone Ranger · · Mumbai Suburban · Joined Jul 2015 · Points: 1,589
John Clark wrote: Is the OP simuling with any kind of progress capture or are they accepting the additional fall length of simuling without proper belay?

Without belay, on terrain that I can solo if push comes to shove.

Edit: no, I can't solo, run out an entire pitch if push comes to shove.

Lone Ranger · · Mumbai Suburban · Joined Jul 2015 · Points: 1,589
Jared Casper wrote:

That's a good question I don't know the answer, but here OPs point stands... lets assume the dynamic elongation for single is measured with an 80kg mass and with a 50kg for a half.  Why is that single with an 80kg climber safer than the half with a 50kg climber?  If an 80kg climber is okay with the 31% the single provides, why can't a 50kg climber be okay with the 32% the half provides. In any case the argument that a half is more dangerous than a single because a half is going to stretch more doesn't hold.

The point is just blindly saying "single" ropes are safer than "half" ropes just because they are designated as "single" ropes is short sighted and naive.  With an understanding of what those ratings mean and taking into account a specific scenario it entirely possible a half rope is a safer/better choice.  The OP laid out some convincing arguments why a specific half rope might be safer/better for his scenario than a specific single, and this thread is a full of people saying that obviously a single is safer than a half solely because it is designated a "single" without providing any reasons or arguments why.

Thanks for understanding my question!

So all the apparel I wear (pants, jackets, hardshell, softshell) are women's because they fit me and no one can tell I am wearing women's unless I tell them. The men's XS in all major brands are way too loose for me. If I were to blindly follow the rule (that Men's were designed for men), I would have to give up alpine climbing.

p.s. I have a normal male body proportion, I am just a small male and I know smaller men. 

Larry S · · Easton, PA · Joined May 2010 · Points: 841

A single rope has to be rated to catch a minimum of 5 factor 1.8 falls (i might be off on that factor a smidge, it's slightly less than factor 2) with an 80kg mass over a rounded edge, typical of a carabiner.  For a long time, typical half ropes would not pass this (but you can safely use single ropes with half rope technique so long as you're only ever falling on one rope).  In recent years, starting with the 9.1mm beal joker, they have had triple rated ropes which can pass all 3 tests - keeping the impact force, stretch, and durability (to catch the repeat falls), sheath slippage, and other UIAA measured factors within the acceptable limis.  I believe the current thinnest/lightest is the Beal Opera 8.5mm, which is rated as a single, double, and half.  The test is the same for a half rope, except with less mass, they must hold 5 falls at FF 1.8 with 55kg.  Double ropes are tested together as a pair with the 80km mass.  

According to Petzl, most half ropes, when tested to the single rope standard, hold 1-2 of these falls (failing on the second or third) fall.  Reference here petzl.com/US/en/Sport/Why-t…

Jared Casper · · St. George, UT · Joined Feb 2006 · Points: 10
Larry S wrote: In recent years, starting with the 9.1mm beal joker, they have had triple rated ropes which can pass all 3 tests - keeping the impact force, stretch, and durability (to catch the repeat falls), sheath slippage, and other UIAA measured factors within the acceptable limis.  I believe the current thinnest/lightest is the Beal Opera 8.5mm, which is rated as a single, double, and half. 

... but you don't get something for nothing.  To pass the "single" test, these ultra-thin triple rated ropes need to have more core material than equivalently sized halfs, so that necessarily means that they will a thinner sheath.  If you are on a climb where it is more important to have a thick sheath to avoid being cut my sharp rocks than it is to be able to hold multiple giant falls before breaking, than a Xmm half rope is going to be better than an Xmm triple rated rope. Neither will be safer than a thicker single that has both a thicker sheath and the additional core material, but that isn't what is being discussed.

I'm certainly no crusher, but analytically it seems to me that these super thin triple rated ropes are really only useful for someone going for a redpoint of their insane 5.18 super proj. (edit: or I guess they'd be useful for hard "backcountry" routes with a long approach, etc.)
Andrew Rational · · Unknown Hometown · Joined Aug 2018 · Points: 10
Lone Ranger wrote: Mammut Genesis half rope: UIAA falls (single rope 55 kg) 12–13! That is more than twice the number of Serenity's falls on 80kg.

I am wondering if people who weigh significantly more than 80kgs, consider their body weight at all in choosing their systems, or is a single rope considered adequate?

Given the wide range of normal human body sizes (I have at least 2 male and 2 female climbing partners that weigh 50kg and 45 kgs respectively, and I have a good climber friend of mine who tips 100+ kgs), I feel  systems should be discussed with reference to actual body weights and not absolutes as in "half ropes" and "single" ropes...One man's half can be another's full?

I can’t really answer your primary question, but as for your secondary question, yes, I do. Naked and dry, I weigh about 105 kilos. Add a trad rack, and other assorted gear/supplies...

I pick fatter ropes for that reason, and also just for durability/longevity. 300 grams (like I think you said) or a few pounds, meh, whatever. Also, fatter ropes make for easier knots in my opinion.

Edit: also, fat ropes are usually far cheaper than exotic ultrathin/ultralight/multiply-rated ones, and I am a cheapskate.
Mike G · · Pennsyltucky · Joined Oct 2017 · Points: 0

I mean you’ve done your research it’s likely reasonably safe, it’s really just up to you to decide if it’s worth it. You call it a confidence rope but how confident are you with a rope that you feel you should retire after a single large lead fall? If you were to take significant fall would you immediately take steps to lower and rappel off your climb or continue to lead knowing you may have compromised your rope using it in a way that’s very much not manufacturer recommended. You’ll be using this on terrain you’re incredibly comfortable on yet the 300 grams of added weight of a full strength single line is a prohibitive factor to you? The other opportunity cost here is you mention durability is a concern and you know you’re putting that second here in the name of saving 300 grams again. So it’s really just up to you if you value that weight savings over every other factor where a full single rope is superior. 

Andrew Rational · · Unknown Hometown · Joined Aug 2018 · Points: 10
Mike G wrote: I mean you’ve done your research it’s likely reasonably safe, it’s really just up to you to decide if it’s worth it. You call it a confidence rope but how confident are you with a rope that you feel you should retire after a single large lead fall? If you were to take significant fall would you immediately take steps to lower and rappel off your climb or continue to lead knowing you may have compromised your rope using it in a way that’s very much not manufacturer recommended. You’ll be using this on terrain you’re incredibly comfortable on yet the 300 grams of added weight of a full strength single line is a prohibitive factor to you? The other opportunity cost here is you mention durability is a concern and you know you’re putting that second here in the name of saving 300 grams again. So it’s really just up to you if you value that weight savings over every other factor where a full single rope is superior. 

This. This is what I was trying to get at. 300g/10oz is negligible, even if OP is light. Like, just hydrate well before the climb, and take a big leak before it. OP could even take a big shit and lose a pound or two, rather than fiddling about with marginal ropes. The rope is usually the single unredundant thing in the system...

Guideline #1: Don't be a jerk.

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