think of it like this.

ropes are springs. i think we can all visualize how using single ropes as half ropes would work. so each rope works independently. When you clip 2 ropes into a piece of pro, it look like 2 springs in parallel. When you do this, you add the spring constants. so if your clipping 2 of the same ropes, you impact force on the piece will double.

sorry if i didnt explain this too well

http://scienceworld.wolfram.com/...ringsinParallel.html

WTF are you talking about man? That's not even what the OP asked...

can you use 10.2mm lines as doubles- sure. however, it is absolutely imperative that the leader DOES NOT FALL before getting one of the ropes clipped on lead. the resulting forces could be deadly.

WTF are you talking about man? That's not even what the OP asked...

Ropes are ropes. Sure, they have a twisted core, but that's about as far as anyone should take it without being a manufacturer. Find sterlingjim on here and ask him.

NOW back to the OP:

Myself being 200 lbs I have no problems climbing on a 9.2 single rope. I also have 8.2 doubles which come in handy. Know that the rope won't break. They may look small but know that my old rope towed a car quite well. it was a 9.8. The skinnier the rope the more stretch. (see twisted core, aka Kernmantle)

FWIW my old partner led and took falls on a 9.2 single. He weighed in at around 260 lbs.

vegastradguy, does your comment about not falling before the first clip imply a new risk that I am not seeing? It seems to me that it doesn't matter whether you are on a single rope or using a double rope technique, if you miss that first clip on an upper pitch you are going to be seriously hurting with a factor 2 fall. Certainly there will be a harsher impact with a single 10.2 rope than falling on one of a double, but that is a risk that single rope climbers face every day.

If you belayed with just the one rope until the first piece is put in and had a bunch of slack in the other so the wouldn't come tight the same you could avoid the situation. But if that first piece ripped and you had taken up the slack in the second rope you would be looking at ripping your belay again.

huh. this seems like a lot of helpfull advice.

Would it make a difference if when the climber is leading off the belay [with factor 2 fall potential and both double 10.2 ropes] if the belayer slacked one of the ropes and kept the other one secure untill that first piece is clipped??

vegastradguy,

While the rist of trying to use two singles as twins seemed obvious, for some reason it took me a few days of pondering your response about the risk of playing doubles with two single ropes, but it finally sunk in. It is really the same risk. Even with chossmonkey's suggestion and caveat, I can see that the risk is too great. If I am going to try climbing with twins or doubles I need the right ropes!

I've often thought of the 7ish mm rap line tied suggested by irregularpanda, but I always have been leary of multipitch with only one climbable rope. I fear the possibility of have have a stuck rope and no way to re climb and retrieve it safely.

vegastradguy,

While the rist of trying to use two singles as twins seemed obvious, for some reason it took me a few days of pondering your response about the risk of playing doubles with two single ropes, but it finally sunk in. It is really the same risk. Even with chossmonkey's suggestion and caveat, I can see that the risk is too great. If I am going to try climbing with twins or doubles I need the right ropes!

What if they used two Beal Jokers? Seems like the best of all worlds to me.

if you're belaying on both lines and the leader happens to fall before they get the first piece clipped, you're looking at a factor 2 with a pair of 10.2 ropes. not good.
...
can you use 10.2mm lines as doubles- sure. however, it is absolutely imperative that the leader DOES NOT FALL before getting one of the ropes clipped on lead. the resulting forces could be deadly.

Factor 2 falls (even if using singles as twins) is not instant death. Common guys, get real.

Factor 2 falls (even if using singles as twins) is not instant death. Common guys, get real. I've had partners take factor 2 falls on a daisy chain (aid falls) and it can leave bruises but it is not the end of the world (I also took a 6~8 fall where I came to a static stop when my fifi hook hooked a piece on the way down).

Singles as twins sounds really bulky and heavy and it will up the impact forces. You will get shorter falls (less stretch), good for blocky climbs where you could hit a ledge, and higher forces on gear, bad if the pro is sketchy or the rock quality is iffy.

When you get down to it, I think you'll survive any of these systems. But I think the one that gives you the best chances for it is the intelligent use of two single ropes. If you decide to use them as doubles, instead of single-and-rap-line, take precautions not to load them at the same time and I think you'll be just fine.

True, on multi pitch (unless you knot the ropes) high factor falls your falling buddy will just give you rope burn until you let go of the rope and drop him to the end of the rope.

I've been reading your posts for years, and usually you don't post anything blatantly stupid. This post, though, is an exception.

Jay

I think using singles as twins (unless they are rated for it like the Joker) is a pretty stupid idea.

But particularly with the thinner, generally stretchier, singles that are out there now, the impact forces just aren't going to be sudden death (is this where I am being blatantly stupid?).

For what it's worth, the maximum impact force is 12 kN for single ropes. Many singles are 8.4 to 10.

The potential for 16- 20kN is way more than I care to deal with.

Don't forget, if they redirect through the anchor you can approximately double the force again that the anchor could see.

How about two 8.3 mil dynamic ropes.. does a fall on these ropes creat more force than one 10.3 and should you always only clip them seperatly on pieces, or can you do them together?

How difficult is the whole concept of half & twin ropes to understand?

I But, I know when using double or twin rope technique, you are more weighed down with those ropes with rope drag passing through your gear, as oppose to having one free rope on the back of your harness and leading with another rope.

I think you have a misunderstanding of the point of double ropes. The reason to use them is to avoid the drag that a single rope would impart on the system on a wandering/confangled route. As far as weight goes, two single ropes are going to weigh more than two half ropes, no matter where you're hanging the second rope from.

--Andy P