heres the response from dead elephant

Hello (name deleted by me),

you had a question on your Mammut rope Phoenix 8mm and whether it can be used in twin and half rope technique in one single pitch. This is the case, you can always clip the two rope strands as twins, then split them as doubles, join again etc. This is exactly the advantage of half ropes compared to twin ropes where you always need to clip both ropes.

Hope this helps you,
best regards from Switzerland,

(name deleted by me)
Productmanager Climbing Equipment

Just happened to find this:
http://www.rockclimbing.com/cgi-bin/forum/gforum.cgi?post=808503

Read beesty511's very long reply, with this:

"Conclusions:
What is to be learned from this accident? NEVER LET NYLON SLIDE AGAINST
NYLON! You should already know this. "

well personally id rather trust the manufacturer than some random RCer

which is why i asked them directly rather than going through the RC "yur gonna die" gongshow

i would think mammut would know what they are doing after 151 years in the climbing business



Hello (deleted),

you had a question on your Mammut rope Phoenix 8mm and whether it can be used in twin and half rope technique in one single pitch. This is the case, you can always clip the two rope strands as twins, then split them as doubles, join again etc. This is exactly the advantage of half ropes compared to twin ropes where you always need to clip both ropes.

Hope this helps you,
best regards from Switzerland,

(deleted)

Freundliche Grüsse / Kind regards
(deleted)
Productmanager Climbing Equipment
Mammut Sports Group AG, Birren 5, CH-5703 Seon
Tel. +41 62 769 81 32, Fax +41 62 769 82 47, www.mammut.ch

You can start out using them as twins and then separate to halves, but do not join them back to twins once separated unless you use two different slings and biners. The problems is that once you separate the ropes, the amount of rope out for each strand and the amount of drag for each strand is different. Accordingly, when you fall the ropes can move at different speeds, which if allowed to contact each other could result in rope damage.

The guy that replied is likely just some grunt from marketing. If you spoke to the senior R&D engineer for Mammut I bet he would tell you something different. Send an e-mail to both Bluewater and Sterling, ask to speak to an engineer, then ask the question again. I bet you will get a different answer.

I'll play devil advocate.
There IS different rope drag for each rope but how much is the question. If able to split and combine at will the rope drag will be significantly reduced. How much is too much if it's even applicable?
Then the ropes are BOTH passing through the biner, so it's not like one is stationary and the other passing over a single point at high speed. The weighted rope will most likely go to the bottom of the biner.

It's all conjecture though. I have believed as you for many years but with the new 7.8mm ropes out I'm looking deeper into it and finding surprisingly little in terms of actual data.

product managers are required to know all the ins and outs of their products and the uses ... its not simply a marketing position

you can see the depth of their USA product manager here ... i bet he knows more than you on ropes

http://www.highinfatuation.com/blog/straight-from-the-mammoths-mouth-things-you-want-to-know-about-ropes/


id rather listen to MAMMUT directly than some RCer like you

not to mention the climbers that climb hard and fall more on doubles/twins than you ever will

someone DID email PMI and bluewater ... you can see the response they got

http://www.mountainproject.com/...vs-twin/107396265__2

remember that unlike RCers saying whatever they want, "safe" usage directions from a manufacturer such as mammut carries LIABILITY

Sure. I mean, its not like I work in the industry and climb with these said marketing guys and engineers or anything. As far as climbing hard, I have climbed grade V 5.12+ and multiple lines on El Cap--that's plenty hard enough. And only a Sharma stocker would actually think that climbing 5.14 gives you an engineering-level understanding of climbing gear. I know because I have climbed with a large sum of them. Some of them dont really know jack outside of how to dyno to a mono.

I am not saying that Mammut's staff are unqualifed. I am sure they all know a ton about climbing. But I have also spoken to Petzl employees that dont know their own Dragonfly rope is not UIAA certified as a twin, and Black Diamond employees that do not know that their pins are made out of chrome molybdenum steel, and the list goes on and on. Hell, the CEO of Sterling ropes isint even a rock climber (not that she needs to be, but one would assume)! So my point is not everyone knows everything about every subject and if a bunch of people are saying something other than what you think the correct answer is, you would be well off to further inquire using many references and sources instead of blindly believing the reference that best supports your opinion is gold.

Look, of course there have been climbers who have rejoined their halves and fallen on them without issue. Safety is a sliding scale. "Safe or not" is a question of your personal risk assumption. I am absolutely positive, no matter how many marketing guys say otherwise, that I could create a system in which you could get enough rope speed difference between the two ropes to cause a problem. I have blazed the sheath of a rope solely from the friction of a carabiner while taking a big space whipper. So if the carabiner alone can damage a sheath from friction, then two ropes in that carabiner, each moving at a different speed, certainly can cause problems under some conditions. Few people realize just how sensitive nylon is to heat (350F causes major strength loss) and how fast a rope can heat up under heavy friction while rubbing against other nylon components. I have seen a climber melt through the sheath of his rope, exposing the core, on a small lead fall because his tag line got caught in the lead line and rubbed against it during the fall. Crap happens.

Hi Charles,

Sorry for the late response to your question. I was away on a short climbing vacation with my family.

So then…

Indeed there has been lots of discussion on this topic and a pretty wide range of thoughts and opinions. Unfortunately the UIAA (the international mountaineering standards writing organization) does not clarify this point very well in the standard document. The standard, UIAA 101 (EN 892) merely states that a rope certified as half is suitable for use in pairs and clipped separately while a rope certified as twin is suitable for use in pairs and must be clipped together into the same carabiner as though they were a single rope. Currently there is no mention of how the ropes should be treated when it has a dual certification.

My personal opinion, as rope engineer and a climber, is that one should choose one technique before starting each pitch and stick with it to the end. Changing the technique back and forth mid pitch would likely create situations where the ropes have the possibility running unevenly (speeds) or even in opposite directions in the event of a fall. This could cause, as you stated, the potential for rope on rope friction, which we know can cause damage to the nylon. While I’ve never heard of a rope failure from such a scenario I see it as one possibility that can easily be avoided by sticking with one technique per pitch. That said, in 35+ years of climbing, and a huge amount of that time with half ropes and twin ropes, I’m certain I have mixed the techniques mid pitch many times without incident. I believe the point I’m trying make here, is to go with the best practices first but when that’s not possible you have to go with what works.

I know this does not clarify the issue much beyond your previous understanding but I hope it helps you make wise choices while you climb. If I can be of any further help feel free to contact me.

Best regards,

Jim

Jim Ewing
Product Engineer
Sterling Rope Company, Inc.

I’ve been trying to imagine some sort of test set up for this issue in years past but it never seems to become a very high priority, unfortunately. If you have some ideas feel free to share them and I’ll try to determine if it is possible to set up a test.

You can start out using them as twins and then separate to halves, but do not join them back to twins once separated unless you use two different slings and biners. The problems is that once you separate the ropes, the amount of rope out for each strand and the amount of drag for each strand is different. Accordingly, when you fall the ropes can move at different speeds, which if allowed to contact each other could result in rope damage.

The "rule" against nylon on nylon contact is meant to prevent a scenario where a running rope crosses a fixed non-moving rope or sling, under load. The friction imparted to the fixed nylon piece can quickly melt through that piece--and this has been well documented.

The situation posed here, however, is quite unlike that. Frankly, I can't envision any scenario where one of the two ropes, upon being separated and then rejoined, would cross the other rope with either of the two ropes being fixed and not moving. As long as both ropes are moving (same direction and different speeds, or different directions) I don't see any problem.

Nylon on nylon contact under load is not always bad, per se. If that were true, Munter hitch belays would be uniformly fatal--and of course, they are not.

Curt

I also ask if he could do a non official test.