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Using Twin Ropes Singly?

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Using Twin Ropes Singly?

Postby Mountainjeff » Mon May 10, 2010 4:49 am

What are your thoughts on using a twin rope, such as the Edelweiss Discovery singly for moderate snow climbs. Maybe for something where there is no danger of a high impact lead fall, but protection would be desirable.
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Postby Autoxfil » Mon May 10, 2010 1:07 pm

For just a tiny bit more weight you can get a light double, which I would much prefer.

Snow only, no glaciers? Simulclimbing with pickets and tiblocs?
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Postby ExcitableBoy » Mon May 10, 2010 4:17 pm

I use a single strand of a half/double rope for moderate alpine climbs frequently and found it works great. I climbed a 4,000 ft north face in winter as a three person team on twins. The leader tied into both ends and the two followers tied into a single strand. The set up was very uninspiring and and I vowed to never climb on a single strand of twin rope again. If the ONLY intended use is as a rope for crossing mellow glaciers it may be ok, but you won't find me doing it.
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Postby Mountainjeff » Tue May 11, 2010 7:52 am

Autoxfil wrote:Snow only, no glaciers? Simulclimbing with pickets and tiblocs?


Mostly just snow climbs in the Olympic Range in Washington. There would be very occasional moderate glacier travel. This rope caught my attention because for many moderate snow traverses where, due to poor runouts, roping up and simulclimbing would be desirable, a 60 meter, 10 mm rope would seem a bit overkill (for a two man team). Pickets would most likely be used.
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Postby mvs » Tue May 11, 2010 9:52 am

Mountainjeff wrote:
Autoxfil wrote:Snow only, no glaciers? Simulclimbing with pickets and tiblocs?


Mostly just snow climbs in the Olympic Range in Washington. There would be very occasional moderate glacier travel. This rope caught my attention because for many moderate snow traverses where, due to poor runouts, roping up and simulclimbing would be desirable, a 60 meter, 10 mm rope would seem a bit overkill (for a two man team). Pickets would most likely be used.


I wouldn't use a single twin for anything, but I definitely used a single double rope for many adventures in the Cascades. It's a pretty common pattern to have a glacier followed by a few pitches of 4th-low 5th to the summit. You just double the rope and simul-climb or make static leads as needed with the 25 meters rope. Yes, get 50 m if you can still find it...it is enough.
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Postby ExcitableBoy » Tue May 11, 2010 2:25 pm

mvs wrote:
Mountainjeff wrote:
Autoxfil wrote:Snow only, no glaciers? Simulclimbing with pickets and tiblocs?


Mostly just snow climbs in the Olympic Range in Washington. There would be very occasional moderate glacier travel. This rope caught my attention because for many moderate snow traverses where, due to poor runouts, roping up and simulclimbing would be desirable, a 60 meter, 10 mm rope would seem a bit overkill (for a two man team). Pickets would most likely be used.


I wouldn't use a single twin for anything, but I definitely used a single double rope for many adventures in the Cascades. It's a pretty common pattern to have a glacier followed by a few pitches of 4th-low 5th to the summit. You just double the rope and simul-climb or make static leads as needed with the 25 meters rope. Yes, get 50 m if you can still find it...it is enough.


MVS is right on. I went from using 50s back when that was all there was available to using 60s and back to using 50s for alpine routes. Steve House is a guy who thinks a lot about the systems he uses and it is no accident he chose a single strand of 50 m, 8 mm rope for his lead line on Nanga Parbat.
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Postby Autoxfil » Tue May 11, 2010 3:02 pm

Using the same systems as SH is a bad idea for people who value staying alive over pushing the limits of alpinism. He solos hard ice and rock on 7-8kM peaks - that doesn't make it a good idea. He recently broke a ton of bones and nearly died taking a roped fall. That's not a safety system I want.

Anyway, his skinny rope was a half, not a twin.

A twin will catch a sliding fall just fine. But, the thin cord is extremely susceptible to damage. A good half is only very slightly heavier, and much tougher in abrasive environments.

In either case, trash the rope if it catches a real fall. Use Tiblocs on the pickets/screws to potect the leader from a slip by the second. Having the weaker climber lead is often a good idea as well - when simul climbing the mantra should be "the second must
not fall".



If weight is the issue, invest in dry-treatment. A 9 mm that repels water will be lighter than a soaking wet 8mm on that last pitch of the day.

I ended up with a short 9mm single. It's more versatile, more durable, and easier to jug out of a crevasse on. Gear Express offers odd-length ropes at good savings.
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Postby drpw » Tue May 11, 2010 4:32 pm

Mammut Genesis is an 8.5mm dry treated double that weighs 6.5lbs for a 60m rope. Kind of hard to beat that.
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Postby mvs » Tue May 11, 2010 4:41 pm

Autoxfil wrote:Using the same systems as SH is a bad idea for people who value staying alive over pushing the limits of alpinism. He solos hard ice and rock on 7-8kM peaks - that doesn't make it a good idea. He recently broke a ton of bones and nearly died taking a roped fall. That's not a safety system I want.


You don't have to do the things Steve House does in order to find a doubled up half rope useful for alpine climbing.

Autoxfil wrote:Anyway, his skinny rope was a half, not a twin.


Yep. I would re-iterate again and again that using a single twin rope is probably not kosher. Doubles all the way.

Autoxfil wrote:A twin will catch a sliding fall just fine. But, the thin cord is extremely susceptible to damage. A good half is only very slightly heavier, and much tougher in abrasive environments.


Exactly.

Autoxfil wrote:In either case, trash the rope if it catches a real fall. Use Tiblocs on the pickets/screws to potect the leader from a slip by the second. Having the weaker climber lead is often a good idea as well - when simul climbing the mantra should be "the second must
not fall".


I do believe in simul-climbing when it makes sense, but I don't like the premise of even considering it with a strong/weak climber pair. When you do that, then you need to think of all this Tibloc technology (does that really work?), and anyway, even if the Tibloc worked and arrested a fall by the second I'd be surprised if the climbers got away without a visit to the hospital. Simul-climbing is for expert climbers who know each other very well...and are willing to die for their partner's mistake...and not blame them in the afterlife. :lol:

Autoxfil wrote:If weight is the issue, invest in dry-treatment. A 9 mm that repels water will be lighter than a soaking wet 8mm on that last pitch of the day.


Why not just have a dry treated 8 mm rope? I only buy dry treated ropes, whether singles or doubles.

Autoxfil wrote:I ended up with a short 9mm single. It's more versatile, more durable, and easier to jug out of a crevasse on. Gear Express offers odd-length ropes at good savings. :lol:


Hey that's a great point! Maybe 50 meter ropes will start falling into this "oddball" category and we'll get nice discounts :D . But anyway, all this advice about using a single half rope for some climbs makes the most sense for people (like me) who already have half ropes, and want to do an alpine climb with some (but not too much) rock climbing.

Happy climbing!
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Postby kayakerSS » Tue May 11, 2010 7:04 pm

Sorry to be the noob here, but what is the difference between a half and a twin? I guess I always thought that they were the same thing.
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Postby jniehof » Tue May 11, 2010 11:21 pm

kayakerSS wrote:Sorry to be the noob here, but what is the difference between a half and a twin? I guess I always thought that they were the same thing.

Half/double ropes are each clipped into separate pro. Twins are clipped together; essentially used as a single rope. The first Google hit for "half rope".
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Postby Autoxfil » Wed May 12, 2010 12:21 am

Note that it's traditionally considered a Bad Idea to use doubles (halves) as twins - this increases the force on the piece if you fall.

BUT, Mammut says all their doubles can be used as twins, and some ropes are certified to be used as both. One rope is even OK to use as a twin, double, or single. I often use doubles as twins, but I keep more slack in one than the other. This is of the most concern with weak protection - ice screws in my case, tiny nuts or manky fixed pro for others.

Twins should NOT be used as doubles.

One of the big reasons people use twins or doubles is so they can tie them together and rappel twice as far.

The other main reason is climbing with three people - with doubles (not twins), you can have the leader tie into both and lead normally, and then bring up both seconds at once, one on each strand. This speeds up multi-pitch three person climbing, which is otherwise often slow and frustrating.
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Re: Using Twin Ropes Singly?

Postby Diego Sahagún » Wed May 12, 2010 12:57 am

Mountainjeff wrote:What are your thoughts on using a twin rope, such as the Edelweiss Discovery singly for moderate snow climbs. Maybe for something where there is no danger of a high impact lead fall, but protection would be desirable.

A real mess
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Postby drpw » Wed May 12, 2010 4:09 am

Autoxfil wrote:Note that it's traditionally considered a Bad Idea to use doubles (halves) as twins - this increases the force on the piece if you fall.


Can you explain this one? How does falling on two ropes increase the force rather then falling on one? Say two 8.5mm doubles vs one 10mm single? I understand how clipping both into some pieces and and only one into another piece could make a mess of the ropes, but how does it add force? I'm sure there's an explanation, just wondering.
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Postby rhyang » Wed May 12, 2010 4:43 am

Autoxfil wrote:BUT, Mammut says all their doubles can be used as twins


Interesting -- where did you read this ? A half rope which is also certified for use as a twin will have both markings, and ratings for each test / usage. An example is the PMI Verglas 8.1 -

http://www.rei.com/product/767452

PMI Verglas 8.1mm x 60m Dry Half/Twin Rope Specs
Weight 42.6 grams per meter
Dimensions 8.1mm x 60m
Dry treatment Dry core and sheath
Impact force (half / twin) 5.2 / 8.9 kilonewtons
UIAA falls (half / twin) 8 / 18
Dynamic elongation (half / twin) 35 / 24 percent
Static elongation (half / twin) 8.9 / 7.2 percent


btw When you use such a rope, it can be clipped alternately (half technique) or together (twin technique), but not both during the same pitch. The reason usually given is that in the event of a lead fall, the difference in the ways the ropes run may cause sheath damage. The only exception in this scenario is clipping to the same piece of pro using different carabiners.

Confusing, huh ? :)
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