A friend of mine just bought a 30m 8mm dynamic twin rope set from rei. I have taught basic climbing classes but have always used 10mm single dynamic and don't know much about twin rope setups. The main use will be in alpine and sub alpine Sierra's.

Can 8mm twin ropes be used for rappelling when tied together?

Yes!

Have fun and be safe!

depends on descender device,
here is a snip from Petzl:

> Can 8mm twin ropes be used for rappelling when tied together?

Certainly can! Very common method.

Cheers

Thanks all for the help...that was what I guessed from reading Freedom of the Hills, but there is no room for guessing when ur climbing.

Try them on belay at a safe place first to get an idea of
how they work.

I would use a munter on a locking biner to save weight.

if the ropes will be used for rock climbing, not just for rappelling, there is a difference between Twin Ropes and Double Ropes.

Make sure you understand the difference.

Twin ropes, when used in climbing, are "both" supposed to be clipped in to every piece of protection. Its best to use a separate biner for each rope at each piece of pro. Twin ropes are often used when there may be danger of one rope being cut on sharp edges in a fall. Each acts as a backup for the other.

Double ropes (because they are stronger) are meant to be clipped in to every other piece of pro. Each rope alternates being clipped in. This is usually done on a very winding climbing route to cut down rope drag.

here is a cartoon example of each:
the carton does not show the twin rope system using separate biners, but it is recommended.
http://www.abc-of-rockclimbing.com/howto/ropesystems.asp

>>>Twin ropes, when used in climbing, are "both" supposed to be clipped in to every piece of protection. Its best to use a separate biner for each rope at each piece of pro.<<<

This is my understanding and taking a trip around the google I can't find any legit source to the contrary....

As long as you always clip both ropes into every protection point you don't need to use a separate biner for each rope. You just treat both ropes as if they are one.

If you are using half ropes (aka doubles) and choose for whatever reason to clip both ropes to a single protection point after having made separate clips earlier in the pitch, or anticipating making separate clips later in the pitch - then you should use separate biners for each rope.

+1

Twin ropes. Use like a single rope. Clip every piece and use
just one biner with both ropes running through it.

Twin ropes are used sometimes single strand for snow climbs
where the loads from a fall will be slight. Also for some
3rd class stuff.

Double them for high angle stuff.

Guys, both ropes in the same biner is not ok.
ropes have a bazaar tendency to unclip themselves.

1. place pro
2. clip 1 biner to pro
3. clip one open sling to biner (don't use a shorty sport draw)
4. clip 2 biners into sling
5. clip 1 twin rope into each separate biner

this essentially works the same as a single rope system with the added safety to prevent both ropes from unclipping themselves simultaneously.

. . .
alpine climber for 25 years.

It's very rare that ropes unclip themselves and usually it's the result of improperly backclipping. If ropes were unclipping all the time there would be a ton more accidents since the great majority of climbers use single ropes and clip protection points with a single non-locking biner.

Imo if you're that concerned about ropes unclipping you would be better served using a light locking biner at each protection point (or at critical protection points) because you would eliminate the chance that in your method the two biners could pinch the rope resulting in rope drag. And it would be lighter and less bulky on the rack than two seperate biners anyway.

...
alpine, trad and ice climber for 17 years if that matters

From- Mountaineering: Freedom of the Hills...(p. 271)

"...approved twin ropes are generally 7.4 to 8.1 millimeters in diameter...."

"The twin rope technique shares some characteristics with the single-rope technique and some with the double-rope technique. Two ropes are used, but they are each clipped in to the SAME PIECE OF PROTECTION, as a single, larger diameter rope would be (fig 14-18)." (bold mine)

The accompanying figure clearly shows both ropes running the same single carabiner on the same piece of protection...That's how I've always seen it done with twins; not to be confused with double-ropes.

since we're relying on published expert opinion :-)

John Long's How to Rock Climb book says
"whenever two ropes run through one anchor they should be clipped into separate carabiners".

He's also not a fan of the Twin rope system, preferring the single rope or double rope system.

Since even the "published experts" disagree I guess we can do whatever we like.

I can accept one locker in place of two biners.

Edited by asandh on 07/22/2010 11:17:11 MDT.

"Guys, both ropes in the same biner is not ok.
ropes have a bazaar tendency to unclip themselves.

1. place pro
2. clip 1 biner to pro
3. clip one open sling to biner (don't use a shorty sport draw)
4. clip 2 biners into sling
5. clip 1 twin rope into each separate biner

this essentially works the same as a single rope system with the added safety to prevent both ropes from unclipping themselves simultaneously.

. . .
alpine climber for 25 years."

I see your point about twisting etc. However
this is a 30 meter rope, fewer placements, less
chance for kinks.

And this is a ultralight web site where we assume
people will use judgement in place of extra gear.

If I was climbing at the difficulty level where twin ropes
in a single biner were causing problems, I would
likely move to a double
rope so I could separate the ropes to
reduce friction. This would likely be lighter than
carrying double the amount of biners and a twin ropes.
Double ropes come in at near 8.5 mm versus twin ropes
at near 8mm.

In other words, if you have to place two biners at each
protection point when using twin ropes, there is no
reason for twin ropes to exist.

Edited by oware on 07/22/2010 11:42:54 MDT.

>>>John Long's How to Rock Climb book says
"whenever two ropes run through one anchor they should be clipped into separate carabiners".<<<


Art, are you sure you're not inadvertantly taking that quote out of context?

He may very well be referencing double rope technique and the occassional need/desire to run the doubles through the same protection point after having them separated prior to that point.

In that case, you do want to run them through separate biners, but it's not because the biners could unclip themselves: It's because when you're using double rope technique you end up with differing lengths of rope out on each rope, and in the event of a fall, because of the differing rope lengths, each rope will pull at a different speed which could cause friction/melting.

If Long is talking about twin rope technique I would be surprised. But hey, he is the guy that taught us all about the virtues of cordelletes before he decided that they were actually less safe than the old methods. So even the experts are sometimes wrong.

Re. John Long
admittedly I took the quote from a picture on the double rope page.
however his next picture labeled "twin rope technique" clearly shows each rope going through a separate biner.

so I figure two biners are preferred in all situations.

for me its a mute point because I don't use Twin Ropes.
can't believe I've spent so much energy on this topic :-)

Ha ha - I don't use them either. And I never will if I have to carry all those extra biners!

30 metre twins seems odd. The main advantage of twins for alpine climbing over a light single rope is abseil range (plus redundancy against stonefall/sharp edges etc) but for that one normally has 50s at least, or these days increasingly 60s. I struggle to see what advantages a pair of 30s would have over a light (9mm, these days) 60 metre single.

For *twin* rope technique (as opposed to half/double rope technique as practiced in UK trad climbing) it is absolutely normal and standard - at least in the Alps, US practice may differ - to clip both ropes as one. Neither rope makers nor the German or Austrian Alpine clubs recommend anything else.

Regarding abseil/rappel technique: twin ropes, esp. when new, are thin & slippery. Watch out for this first time down, and be sure to use a backup prusik as you always should anyway.

(I grew up with UK trad climbing on double ropes, do some sport & gym climbing on singles, and recently started doing multi-pitch bolted stuff in the Alps on twins)

Edited by AlanL on 07/26/2010 10:18:18 MDT.

The 30 meter (most seem to be 38 meters or so) 7.8 mm ropes are sold for glacier travel.

There are lots of Sierra Nevada Peak climbs that have only a
few meters of roped climbing or have snow gullies to cross,
a narrow but wild stream to tyrolean or tarzan across,
or a short rappel down a canyoneering route.
The advantage to owning 30 meter twin ropes is some trips
you only need to carry 1 of the pair, and not a full 50 or 60
meter rope.

I usually just cut an old double ropes in half for this use,
but a twin would be a bit lighter.

Edited by oware on 07/26/2010 19:06:13 MDT.