Double Rope Systems

We have been discussing a method of rope manufacturing with a 2 rope system that ponders a question.

I have ropes that are manufactured for the UIAA designation of double and twin (1/2 and infinity). Does this designation allow for interchangeable method while climbing? Or is the intent for the climber to use either a twin method or a half method while on a pitch.

The problem goes to performing alternating/independent protection clips then protecting a traverse with both ropes in the same protection placements along the traverse.

If a fall occurs both ropes do not absorb equal force possibly causing one rope to friction against the other. Also, say you use 2 slings on the same protection piece to keep the ropes separate, you have 2 carabiners that are not loading properly (ex. 2 biners loading on one ice screw hanger - would this load the hanger improperly?).

Any comment is welcomed.
Mark N.

Mark, I have one of the Beal Stinger ropes which are certified as single, half and twin. The promotional material states that it can be used in all three situations depending on the type of climbng, but once you start up a pitch you must not change from from twin to double, etc.

So to answer your question, my understanding is that rope can be used as either a twin or a double but not at the same time. Have you tried the manufacturer's web site for any info?

By the way, I used to climb pretty much exclusively apline back home using thin twin ropes and always felt that it was the best way to go. However, you have to treat them as one one!
Cheers, John

PS: If you want to read more about how ropes are made, tests etc this is a good pdf.

mammut.ch/mammut/uploadedFi…(2).pdf

Thanks John,

One of my friends checked with Edelweiss (both our manufacturer). His notes indicated an interchangeable method while climbing on a pitch was their intent when they designed their rope. Though more force on the traverse placement would be generated than by a single rope.

A concern remains on how the ropes react as to friction on the same carabiner when one receives more force than the other. Is this a concern?

Also using 2 carabiners on the same placement to separate the ropes seems like a bad idea to me.

Mark Nelson wrote:Thanks John, One of my friends checked with Edelweiss (both our manufacturer). His notes indicated an interchangeable method while climbing on a pitch was their intent when they designed their rope. Though more force on the traverse placement would be generated than by a single rope. A concern remains on how the ropes react as to friction on the same carabiner when one receives more force than the other. Is this a concern? Also using 2 carabiners on the same placement to separate the ropes seems like a bad idea to me.

Mark, Its a while since I did a lot of climbing with twins but, the golden rule was that you had to treat them as one rope, always clip them into the same biner, etc and make sure that they are weighted equally. If they aren't weighted the same then there was always the possibility you could be subjecting the ropes to some shealth melt.

If you aren't treating them as twins, but doubles then they need to be clipped into separate gear.

Hopefully, someone who uses twins and doubles more will pipe in soon.

I had some interesting discussions with Beal recently and I thought I would share what I learned. Any time you use double ropes you should not clip both ropes into every piece, as you are increasing the shockload on your protection to dangerous levels. Half ropes are rated to catch falls individually. With ropes rated for both double and twin systems you cannot switch from one system to the other mid-pitch unless you clip both ropes into separate biners when in twin configuration. The issue as stated previously is the friction created by the ropes rubbing on each other. With a big enough fall this friction is easily enough to melt nylon. Consider how in a large fall on a single rope you can easily burn your sheath on the top carabiner. Now if you have two ropes absorbing force at different rates due to unequal distribution (different pieces clipped) and both ropes forced together in the bottom of the carabiner, the result could be disasterous.

My take on this is if you are climbing in alpine settings (where double or twin ropes are mostly used) that a twin-rope system is superior. Usually in this terrain there are alot more sharp edges which could cut a rope. Also you tend to have less gear so you are running it out often. Under these situations having both ropes clipped into every piece is much safer.

I climbed using double and twin ropes almost exclusively for about 8 years, but I have to say I have converted to using a single 9.4 and a static 7-8mm for retreat/rappelling. This system holds up at least twice as long (skinny twins don't last in the alpine), is much less expensive, and gives you much more flexibility in rescue situations (ever try a 3-1 haul with a dynamic 8mil?). Anyway that is my 2 cents.

Thanks to those that had reviewed & responded to my initial inquiry regarding proper use of a 2-rope system. I just received a reponse from Edelweiss regarding their intent of use for a rope with 2 UIAA designations, double and twin (half and infinity). It appears that the commonsense approach in using one method or the other while climbing a pitch is proper, and not an interchangeable method. Mark N.

Dear Mark,
Sorry for the late reply to your question.

1. Using alternate method (double and twin) on one pitch. The answer is no, you use either a twin method or a half-rope method, not a mix on the same pitch.

The reason is the one you mention: friction between the two ropes that would lead to burning the rope in case of a fall.

2. Clipping two slings on the same protection point. This is of course possible, but not recommend on ice, where alternate clipping is strongly recommended because of the impact force generate on that protection point. I would use alternate clipping even on a traverse.

3. On double ropes you can have two seconding climbers, while twin
ropes do not allow this possibility.

Hope this helps.
Have fun climbing,
Philippe

Hold the damn phone, I received another response from Edelweiss that might contradict everything just posted. I've asked for a reclarification from Herve & Philippe.
Mark N.

De : Herve Fontbonne
Envoyé : jeudi 2 février 2006 16:56
Objet : 2 rope systems - Technical Question

Dear Sir,

Thank you for your interest in our products.

With this rope (8,5 Calanques) designed for double & twin UIAA standard, you can change the clipping method when climbing.

But you have to know that double method is better to have a low impact force; with twin method the impact force will grow about 20% to 25% on the clipped point.

Also separating the strands reduces drag and allows all the rope’s length to absorb a fall’s energy.

So if you climb on uncertain runners you must separate the strands to reduce the impact load.

With bomb-proof runners it’s not necessary as there’s no risk of failing because of a too-high impact force, more often it’s preferable to clip both strands together to resist more repeated falls and lengthen with extenders to bring runners in line with the rope.

Yes a double rope also allows 2 seconding climbers to follow on 1 strand each.

Hope this will be helpful.

Best regards

Mark Nelson wrote: With this rope (8,5 Calanques) designed for double & twin UIAA standard, you can change the clipping method when climbing.

Philippe clarified what the term "climbing" meant; which is to keep each pitch independent.

Mark,
I confirm you can change climbing technique from double to twin or twin to double from one pitch to the other, so during the climb, but not mix double-rope technique and twin-rope technique on the same pitch.
Best regards
Philippe

John McNamee wrote:Mark, I have one of the Beal Stinger ropes which are certified as single, half and twin. The promotional material states that it can be used in all three situations depending on the type of climbing,...

Yo John:

I was reviewing some comparative info on the rope systems, and noticed that Beal only has the Joker (9.1mm) listed for all 3 standards.

The Stinger III (9.4mm) being only a single standard;

the Ice Line (8.1mm), Cobra II (8.6mm), & Verdon II (9mm) as half/double standard;

Then the Ice Twin (7.7mm) as their twin standard

bealplanet.com/produits/ang…
bealplanet.com/produits/ang…

Is this accurate? (Just trying to get info)

Mark,
I'm sorry I meant the Joker.

It's a nice thin rope but I won't be buying another one; it's a real snake when it comes to handling!

Thanks, I think the only strand on the market meeting the 3 standards is the Joker (from what I could find). But it sounds like that strand is a bugger to manage. I guess I'll stick with the 8.5mm half/double strands, they have worked well for me - thus far.

I don't normally buy Beal ropes and did on this occasion just to test the waters to see if they had improved. They hadn't!

Over on supertopo there has been some discussion about ropes so you might like to check out these links:

thebmc.co.uk/safety/tech/ar…

bstorage.com/speleo/Pubs/rl…

uiaa.ch/web.test/visual/Saf…

These certainly make you think about some of the common rope beliefs.

Supertopo rope thread

As for the concern about clipping each rope into a separate biner, I do not believe this will be an issue as the only time that the piece would be cross loaded is when it is not the top piece, and as such the loading would be minimal. When falling on a piece with both ropes clipped in, one rope is going to be absorbing the majority of the fall (if you had used the ropes in a half-rope configuration previously).

I know this is slightly off subject, but I wonder if double ropes are going to eventually go extinct. With single ropes decreasing in size and weight, and with innovative products like the Revolver carabiner I feel that their advantage is decreasing. Personally I now prefer to climb on a single 9.4 and trail a 8-mil static as I feel this system is both easier to use and is much more durable. It is also a lot cheaper to replace a single rope than a set, and a static haul/rappel rope lasts a long time. Just my opinion though....

This brings up an interesting thought though maybe I should start another thread. It seems that a lot of ice climbers use double ropes but though my ice climbing is limited there seems to be fairly limited meandering on most climbs. I understand the desire to have two ropes for the descent but other than that why not twins or a tag line? Is it a safety net for when you slam your crampons into one of your ropes?

Kevin Stricker wrote:I know this is slightly off subject, but I wonder if double ropes are going to eventually go extinct. With single ropes decreasing in size and weight, and with innovative products like the Revolver carabiner I feel that their advantage is decreasing.

I'd say you're on the subject.

You may be right in that we will see half/double ropes go extinct. I think we will see single ropes being manufactured to where they will be similar to the half/double ropes. As single & double strands are similar in certification standard with the exception of using different falling mass (80kg vs 55kg). If a single rope is able to be manufactured at 8.5mm and can limited force to 8kN with 80kg falling mass with max 40% extension & able to hold 5 falls (this is a hybrid of the two standards), then what would the half/double standard serve a purpose for?

(With 80kg falling mass)
Beal is so close to this with the Joker (9.1mm) - 8.2kN - 53g/m

In looking at Edelweiss (with a 80kg falling mass)
- the Laser 9.6mm is a single rope at 8.0kN, - 61g/m
- the Sharp @ 10.5mm is another single rope at 8.0kN - 73g/m

PMI (with the 80kg falling mass)
has the Elite @ 9.4mm with 7.9kN - 57.4g/m
and the Arete @ 9.7mm with 7.9kN - 62.6g/m

Blue Water
Lightning Pro @ 9.7mm with 7.8kN - 61g/m

From Lanex:

9.2 Master (9.2mm) 6.8kN - 53g/m
9.7 Master (9.7mm) 7.6kN - 61g/m

(all of these are less than 40% dynamic extension and able to hold at least 5 falls)

So then we are just talking about weight reduction. If the rope manufacturers can make an 8.5mm to perform with acceptable results using an 80kg falling mass, then I could also foresee the half/double standard becoming obsolete.

Good point Kevin.

Another contender for lightest single rope:

Mammut Serenity: 8.9mm, 9.5kN impact force, 29% dynamic elongation, 5 falls, 52g/m weight (6.9 lbs. for a 60m).

Ron also has brought something to my thought with Mammut. It looks like Mammut is not shooting their technology goal to achieve 8kN as a target (in looking at their product specs offered on their other ropes too). It looks to me that their products are keeping the higher kN (9 to 9+kN) by using less dynamic extension; but then manufacturing their ropes to be lighter & more manageable. So looks like they want to offer a different type of rope performance to the market.

In this case, the half/double standard would stay. So if competitors are going for lighter single ropes to achieve and replace the half/double standard; they will have to beat Mammut in rope manageability.

I find my PMI & Edelweiss ropes do perform well in manageability (totally a subjective standard - based on elbow strain and frustration factor at each belay & rap station), but I have found Mammut ropes are better to manage when I have used them in climbing.

So just going for standard numbers might not be what the market wants in climbing performance & enjoyment. This also could depend on the application of the climb. But, 52g/m @ 8.9mm is pretty similar to a sturdy 8.5mm half rope - I doubt a team would notice any weight difference in just going with a couple of single standard Mammuts, regardless of application. As long as the leader doesn't clip both ropes to the same biner on the pro, force can still be managed effectively on the pro.

The more I think about these methods & products, the more variables I come up with. I think I'll just go to Zion with a single rope, a static line, & haul bag, and just find a bivy on the wall and drink a beer; my head hurts.