Toproping with two ropes joined by a double fisherman's

Question

The other day we were waiting in line for a popular 200 foot single pitch climb in the valley and the party in front of us was using two 70 meter ropes they had joined together with a double fisherman's as a top-rope. I had never seen or heard of this being done before and I can think of a couple of reasons why I wouldn't be comfortable doing this myself:

• Amount of rope stretch in 140 meters of dynamic rope
• Amount of rope drag on less-than-vertical routs when using 140 meters of rope
• The knot getting caught in a constriction or on a ledge
• Increased rope-abrasion where the knot is tied, since the rope rubbs on the rock when the rope is weighed with a climber during lowering
• Not being able to belay a climber all the way to the anchor, since the knot is going to interfere with the ATC if the climb is not exactly the length of the rope tied to the climber, potentially rendering the retrieval of the anchor dangerous, or endangering a novice climber who doesn't notice that the rope is not advancing any more as they make forward progress.
• ...

I can also think of a couple of reasons why there are certain situations where this minght be the smaller of two evils:

• An unexperienced climber does not have to rappel
• In a situation where the weather is fickle, no-one has to belay from the top, expediting the process of getting everyone off the rock faster, at the expense fo leaving the anchor at the top
• When climbing with several novice climbers, the most knowledgable climber can stay at the ground to help with tying in and crowd control at the base of the climb.
• Reducing the wait on popular routes (This is more of a convenience...)

Does anyone know if using two ropes as a top-rope is condoned or discouraged by professional guides? Also, has anyone heard of any accidents or close calls that have happened when using two ropes in this manner? Does anyone know of any testing that has been done on this technique?

Feel free to add benefits or disadvantages that I have missed.

Answer 1

The Ethic

So, the ethic among experienced climbers is to not toprope on the base of a popular multipitch route. In addition to the safety issues you point out, its just not fair to the people who invested the time to learn to lead. Especially not a destination place like Yosemite Valley where people may have traveled a long way to get there. You say this was a long single pitch route, so maybe its a grey area. But a large group of beginners would still be better served by going to a smaller cliff that was more setup for group toproping.

Saftey issues

I did this once when a partner and I (not a group, just the 2 of us) wanted to toprope a very hard route that shared an anchor with a moderate route we'd just lead, and it had the exact disadvantages you mention (basically point-for-point, you identified them correctly). The biggest are:

• The knot / rope can get stuck in a crack. If that happened, you'd have to perform a rescue, which would require (if nothing else) a 2nd rope and a pair of very experienced climbers. If there's only one experience leader, and he/she is the one belaying, you're basically going to have to go for help. (sounds theoretical, but it happened to me personally once with a regular toprope, and a knot only makes it more likely).
• Because there's a big knot at the mid point of the line,the belayer has to "pass the knot", which can be done safely, but is quite tricky, requires experience with rescue techniques, and communication with the climber. Too complicated for toproping!
• The rope-stretch becomes long and nearly unpredictable at that point. With the full length of a 60m rope, you'll get about 15' of rope stretch, the first 5' of which is almost a freefall. I personally don't like to belay a beginner on the full length of a 60m rope, and the system you propose is more than twice that long. You have to remember that beginners don't know how to fall yet, and might do any kind of crazy thing during the fall, getting hurt where an experience climber wouldn't. And even if they didn't get hurt, the rope stretch could really freak them out.
• To compensate for the rope-stretch, the belayer has to put a huge amount of tension on the line, almost sitting his / her full weight on it. That's going to mess up the climber's balance some, too. Frustrating for everybody.

The leader's responsibility

When you take beginners out, you (as the experienced climber) have to be responsible for all aspects of their experience, both keeping them safe, and trying to keep them from getting freaked out. Its actually a lot of responsibility. And when you have then bouncing around on a 140m line, 200' off the ground with up to 30' of ropestretch, you just can't do that. :)

Where to look for more information

• AMGA offers a "Single Pitch Instructor" course which focuses on toprope site management. Its only available as a multiday course, and their info isn't available for free online.
• The annual issues of "Accidents in North American Mountaineering", published by the American Club, here, are a good to read, but they only include accidents that were reported to the park service, usually ones that required a rescue. Minor accidents, or accidents where the climbers could rescue themselves, may not make the report.
• All rope manufacturers publish elongation statistics, as one of the metrics the UIAA requires them to test. These vary between ropes.

Answer 2

This is why I would not do what that group was doing. It would be safer to just lead this route and/or do a top-belay if possible.

Let's look at this simply from a safety standpoint, and more specifically rope stretch.

A 200 foot single pitch top-rope climb means 400 feet of rope from top to bottom and back.

Common dynamic rope dynamic elongation (falling) specs range from approximately 25% - 35%, with the maximum being 40%.

The maximum static elongation (not falling, just hanging) is 10%.

This spreadsheet shows how much the rope would stretch when falling from a given height and at different elongation percentages. The red numbers indicate where the fall height and rope stretch are essentially equal.

I do believe this speaks for itself...but just to make it clear: If you were 36 feet (11 meters) off the ground and you fell, you'd deck at 10% stretch.