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outdoorsie
Aug 5, 2003, 8:24 PM
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Well, I searched the forums for an answer to this and didn't find one, so I'll go ahead and bug everybody to see what you think.
My fiance and I want to finish off a couple of climbs this weekend that require 2-rope repels. We can borrow a friend's rope, but his is static and ours is a Sterling EXTREMELY-dynamic (that's on the label) rope. I'm serious, it's like a bungee cord. Anyway, I would imagine that mixing the two might make the repel... interesting, but my first instincts say that it shouldn't really matter.
Am I way off? Is there some rule that says mixing rope types on repel is bad, bad, bad? Or should it be no big deal?
Thanks!
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hellclimber
Aug 5, 2003, 8:33 PM
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Have no idea but couldn't you just do a single line rappel? Join the two ropes using some safe knot (well, duh) Secure the rope on the top by tying it off. First person raps down. Ties the dynamic line to an anchor. Second raps down on the static line (assuming you've joined the two ropes together here). Then pull rope and repeat if necessary until your feet gently touch the ground. Haven't really thought this through but it sounds like a reasonable solution.
hellclimber
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sticky_fingers
Aug 5, 2003, 8:49 PM
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I would not mix ropes....they might repel more :P
Seriously, though, I wouldn't. Even if they were the same size, which I doubt they are, the elongation might cause you to finish rappelling one rope before the other. hellclimber's idea isn't bad. Are there belay stations relatively close to the rappel route? If so, just break up the descent into two or more pieces and you won't have to worry about 2 ropes
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outdoorsie
Aug 5, 2003, 9:17 PM
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Well, the second pitch of one of the climbs starts out with a pretty cool traverse... you actually have to work your way through a slot in the crag to get through to the other side... Anyway, I'm thinking the repel achors on top aren't going to drop you anywhere near the anchors on top of the first pitch. Which is probably why they recommend 2 ropes- so you can drop straight down.
And I don't think I get how you can "pull the rope" after fixing it on top for a sing-line rap. Maybe I'm missing something...?
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thegreytradster
Aug 5, 2003, 9:20 PM
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The big worry would be differential stretch sliding the rope on the anchor point. I'd take some chain repair links or rap rings in case they weren't in situ. Absolutlely NO nylon to nylon contact alowable in this situation! Other than that, no problem. Done plenty of raps with fat 11's and skinny 9's. almost the same thing. no problem.
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jt512
Aug 5, 2003, 9:21 PM
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In reply to: I would not mix ropes....they might repel more :P
Opposite ropes attract. Similar ropes repel. Don't you know any fisix?
-Jay
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wigglestick
Aug 5, 2003, 9:26 PM
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It is fine to use one static and one dynamic. The difference in the elongation is negligible. Hellclimbers solution is unnecessary and probably even more dangerous. Just tie knots in the end of the ropes if you are worried about rapping off the shorter rope.
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hellclimber
Aug 5, 2003, 9:26 PM
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In reply to: And I don't think I get how you can "pull the rope" after fixing it on top for a sing-line rap. Maybe I'm missing something...?
Yes. Missed a step there. Thought it was obvious. After the first has rappelled down you set up the rope on the top as you would on a double line rappel. One end is secured by the person at the bottom. The person at the top rappels of the other rope (make sure you go down the right rope here :wink: )
Hope that helps.
hellclimber
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alpnclmbr1
Aug 5, 2003, 9:27 PM
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It is normal to use two different size ropes or a second static rope to do long rappels. You don't want to do this directly off of sling anchors because the difference in stretch can cause the rope to move(melt) relative to the anchor. Also be careful that the knot joining the ropes is not going to get jammed (stuck) into the anchor rings. When using a skinny second rope, you want to make sure that it is the one that you pull.
Careful about this info on this site, a lot of it s**ks.
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ambler
Aug 5, 2003, 9:33 PM
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In reply to: In reply to: I would not mix ropes....they might repel more :P Opposite ropes attract. Similar ropes repel. Don't you know any fisix? -Jay |
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vegastradguy
Aug 5, 2003, 9:54 PM
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in short, yes, you can.
a few things to remember (along with what is mentioned above):
1) make sure your static reaches the next anchor, since it doesnt stretch, it needs to be long enough to make it to anchor. we have a 65m static and a 60m dynamic for those extra long rappels, where we rely on rope stretch to get down.
2) use an autoblock, rapping on a static and dynamic line is a little different, since the dynamic is stretching but the static isnt.
3) set it up so you pull the static line. this makes rope pulling MUCH easier.
4) check your knot often, especially when using a smaller static (we use a 9mm and a 10.2 dynamic).....
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sspssp
Aug 5, 2003, 9:57 PM
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I've done plenty of raps in this scenerio.
The only "problem" I know of to be aware of is that as you rap down, you can get a bit of rope "creep". This can happen when the ropes are different sizes and it seems to be worse when one is dynamic and one is static (when you take your weight off the ropes--stepping on a ledge, for instance--the dynamic rope will constrict and tend to pull the static rope back up, especially if the static rope is much smaller).
I can usually prevent this by grabbing both ropes snugly with my left hand above the belay device (this assumes you don't have to use your left hand to control a backup such as an auto-lock). You can also prevent this by putting the knot on the appropriate side of the anchor, because the ropes will only creep in one direction (the smaller diameter rope tends to go up).
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iamthewallress
Aug 5, 2003, 10:25 PM
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In reply to: When using a skinny second rope, you want to make sure that it is the one that you pull.
If you are on a multipitch rap and have one lead line and one static skinny cord or half rope, there is an advantage to pulling the lead line. Namely, if it hangs up, at least you have some lead line to work your way back up to the stuck rope. A friend of mine once had to rap 4 pitches off of a wall and then climb 3 up another one to rescue a couple of guys who, following a 'Quick Clips' tip that they had read were pulling their 8mm retreival cord. If they'd have had just a little lead line to work with they would have avoided this rescue.
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jt512
Aug 5, 2003, 10:42 PM
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In reply to: When using a skinny second rope, you want to make sure that it is the one that you pull.
I disagree, if one rope is static and the other dynamic. I'd want to pull the dynamic rope, so I could safely re-lead the pitch if the ropes got stuck. This is more important IMO than whether the ropes slip, provided that you are not running the ropes directly thru slings and that you have plenty of rope to reach the ground or the next rap station.
Edit: Oops, I should have just said, "What Iamthewallress said."
-Jay
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sspssp
Aug 5, 2003, 11:04 PM
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In reply to: If you are on a multipitch rap and have one lead line and one static skinny cord or half rope, there is an advantage to pulling the lead line. Namely, if it hangs up, at least you have some lead line to work your way back up to the stuck rope.
Because of this, I have gone to using an 8.1mm dynamic as my trail/rap line. Not that I would be thrilled to lead on a single 8.1mm, but if my other rope was stuck/lost/damaged and I had to keep leading to get down safely, I certainly would.
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iamthewallress
Aug 5, 2003, 11:07 PM
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In reply to: Because of this, I have gone to using an 8.1mm dynamic as my trail/rap line.
Because of this I've gone to using two 8.1 mms as my lead/rap lines. :wink: Not really. It's usually just easier to lead w/ twins than to drag a rope.
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passthepitonspete
Aug 5, 2003, 11:53 PM
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Dr. Piton is amazed that not one have you has described the Better Way of rappelling with two different ropes.
First of all, don't join different ropes using a Euro Death Knot - this is the Better Way for joining two identical ropes, but you could end up dead in this scenario by joining two different ropes with a EDK.
The answer is very simple:
Feed your tied ropes through the rappel anchor. On the "knot side" of the rappel anchor, tie an alpine butterfly knot in the rope. Make sure the butterfly knot is between the anchor and the rope-joining knot. [If you are unfamiliar with the Better Way, and enjoy wasting time and fighting tight knots, substitute a figure-8 on a bight for the butterfly]
On the "other side" of the rappel anchor, clip a locker around the other rope, and also clip the locker to the loop in the butterfly, and lock it.
Voila!
You can now rappel down the single rope on the other side! When you get down, pull the opposite end to retrieve the rope.
Note: This is not a Dr. Piton invention. I stole it from the Petzl catalogue, where they describe how to do a double-rope rappel using a Grigri as a rappel device.
The Petzl catalogue is FUNDAMENTAL READING for all. If you do not have a Petzl catalogue, GET ONE! It's possibly the best single source of technical climbing information available anywhere.
And the best part is - it's free.
I am Dr. Piton,
and I am one cheap bastard,
[but I know where to find out good stuff]
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thegreytradster
Aug 6, 2003, 12:18 AM
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The Petzl cat. is a wealth of info. and required reading! Even if it is written by "them cheese eatin surrender monkeys" Homer Simson
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outdoorsie
Aug 6, 2003, 2:53 PM
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Oh wow, That is an interesting idea... so you kind of get a lasso (on a beener) around the anchors...? Cool.
I think we'll be at the gym tonight for a couple of hours experimenting and trying these different ideas. Thanks for all the advice!
Also, sorry about the spelling. 4 years of college, 3 in industry, 2 of climbing and I never learned how to spell "rappel". It's sad, really.
And as a totally unrelated side note, check out m-w.com's definition for rappel:
"to descend (as from a cliff) by sliding down a rope passed under one thigh, across the body, and over the opposite shoulder or through a special friction device"
Ouch!
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sspssp
Aug 6, 2003, 3:06 PM
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In reply to: Feed your tied ropes through the rappel anchor. On the "knot side" of the rappel anchor, tie an alpine butterfly knot in the rope. Make sure the butterfly knot is between the anchor and the rope-joining knot. [If you are unfamiliar with the Better Way, and enjoy wasting time and fighting tight knots, substitute a figure-8 on a bight for the butterfly] On the "other side" of the rappel anchor, clip a locker around the other rope, and also clip the locker to the loop in the butterfly, and lock it.
Well, yea, but isn't this whole mess a lot more likely to jam? And I'm not too keep on having a biner come whipping down at me when I pull the rope.
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sticky_fingers
Aug 6, 2003, 3:08 PM
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In reply to: Oh wow, That is an interesting idea... so you kind of get a lasso (on a beener) around the anchors...? Cool. Also, sorry about the spelling. 4 years of college, 3 in industry, 2 of climbing and I never learned how to spell "rappel". It's sad, really.
that's ok...I'll forgive you on the spelling, but we GOTTA do something about your hated for Mexican-Americans. I mean really...if lassoing someone isn't humilitaing enough, now you want to tether them to a boat anchor? I'm sorry sir, that's where I draw the line.
i spy a missing i
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sspssp
Aug 6, 2003, 3:09 PM
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In reply to: Because of this I've gone to using two 8.1 mms as my lead/rap lines. :wink: Not really. It's usually just easier to lead w/ twins than to drag a rope.
I've done this some, too. However, even after doing it for a while, the rope management still slows me and my partner down. The second ends up waiting for the leader to pull up/manage ropes while trying to climb up, especially on the moderate pitches.
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outdoorsie
Aug 6, 2003, 3:18 PM
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In reply to: i spy a missing i
:: Outdoorsie sticks her tongue out at you. ::
:D
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joegoesup
Aug 6, 2003, 4:30 PM
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I have a 60 meter length of 8 mm cord I use regularly with my 10.5 climbing rope. I join them with a overhand knot with about a foot of tails. I have never had any problems. Rock and Ice recommended the overhand a few years back and I found it doesn't get hung up as much as the double fisherman.
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climberer
Aug 6, 2003, 6:09 PM
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In reply to: Well, yea, but isn't this whole mess a lot more likely to jam? And I'm not too keep on having a biner come whipping down at me when I pull the rope.
Well if you pull the right end - and i don't see how it would be possible to pull the wrong end - the biner should be in your hard before the rope starts falling. Think about it. :P
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