Scenarios for Passing a Knot on Descent

[Turtle]

I've been trying to think of some scenarios in which one would need to pass a knot on descent. I can only think of several "oddball" scenarios (a rappel for which the rope will not be retrieved, a very long rappel rigged macrame), each of which presents challenges and problems of its own that are likely more dire than passing the knot.

The strangeness of these scenarios is motivated by a common dififculty...

How is it possible to retrieve a rope with a knot inline on the weight bearing side of the anchor?

Are there any methods that are better than macrame for a long rappel when you're (presumably, based on the need for the knot) a bit short on rope and cord?

[Paul Nelson]

How about a guided rappel and the rope is not long enough for the descent line and the guide line, so you tie another rope to the descent line. The block is now on the descent side of the rope being held under tension by the guide line.

When everyone is down, untie the guide line. Then pull on the descent side of the rope for the pull down.

[charlybldr]

You pull your rope after a drop and notice a core shot. Even though you try to be careful, the core shot gets worse after each rap. Rather than let that happen, you can remove the core shot with a butterfly knot.

You will now have to pass this knot at every rappel. If you didn't already have your system dialed, you will by the time you get to the end of the canyon.

Charly

[rcwild]

Add to Charly's core shot example. Depending on where the core shot is located, it might not be possible to rig blocks. You might have to settle for toss-n-go. So there's only a knot in one strand, but you will have to pass it while rappelling on both strands.

and ...

Heaps. Common tactic is to stash 300 foot rope at the base of the last rappel ahead of time. Two shorter ropes are used to descend the canyon. At the top of the last rappel, two ropes are tied together so they'll reach the groun. Only one person has to pass the knot. That person retreives the rope connects it so it can be pulled to the top. Rope is rigged so 300-footer is rap line; knotted rope is retrieval line.

[Turtle]

Thanks to all for the input...


[Y]ou can remove the core shot with a butterfly knot.

You will now have to pass this knot at every rappel.

This is actually one of the scenarios that I thought of that led to my wondering about retrieval options for setups with a knot on the weighted strand.

Suppose it's a 60 m rope that has the core shot 15 m from one end...

For raps < 30 m, you can rig a block (or I suppose even a contingency with 15 m of available payout) with the alpine butterfly on the retrieval side. No need to pass a knot.

For 30 m < raps < 60 m, you're presumably looking at incorporating a retrieval cord. (If you had another full strength rope, why wouldn't you use it and rig as above?) Connect the retrieval cord, block on the retrieval side, rap past the alpine butterfly on the weighted side. But now how to retrieve?

This is what had me thinking of 60 m macrame retrievals, which I'm assuming is less than ideal...

[rcwild]

This is the kind of scenario I was talking about when I said you might want to just rig them toss-n-go. But you could rig them so nobody has to pass a knot.

Feed out enough of the good end of the rope to reach the ground. Secure it to the anchor with a knot (figure eight, clove hitch). Everyone rappels on the good end. Last person converts to a macrame (or OmniSling or whatever), making sure the knotted side is the retrieval side. Last person rappels on the good end of the rope after the retrieval system is set up. Knotted side off the rope is only used for pull.

[ratagonia]

Heaps. Common tactic is to stash 300 foot rope at the base of the last rappel ahead of time. Two shorter ropes are used to descend the canyon. At the top of the last rappel, two ropes are tied together so they'll reach the groun. Only one person has to pass the knot. That person retrieves the rope connects it so it can be pulled to the top. Rope is rigged so 300-footer is rap line; knotted rope is retrieval line.

Passing the knot - hoooooow twentieth century ---

It is also possible to do a "Lower and Rappel". The victim sets a rappel below the join knot between the two ropes. A lower is set up just above the knot. Over the edge. The victim rappels while being lowered. Faster, slicker, no passing the knot. Requires some degree of rapport between lowerer and loweree. Also requires a physical geometry where lowering is reasonable.

Similarly, one can also do a self-lower and rappel. Set up a rappel below the device, and lock (mule) it off. Set up a lowering system off the knot going upward, for instance a munter on a biner off the knot. Lower yourself the upper part (ending with the biner locked in place); then rappel the lower part. A complex system, prone to many difficulties. Munters produce a great deal of twisting, that can lead to serious problems.

And sometimes it is just easier to pass the knot.

Tom

[rcwild]

It is also possible to do a "Lower and Rappel". The victim sets a rappel below the join knot between the two ropes. A lower is set up just above the knot. Over the edge. The victim rappels while being lowered. Faster, slicker, no passing the knot. Requires some degree of rapport between lowerer and loweree. Also requires a physical geometry where lowering is reasonable.


Ah, yes. The system I taught to you during your ACA basic course in Arizona a few years ago.

[sonnylawrence]

A complex system, prone to many difficulties. Munters produce a great deal of twisting, that can lead to serious problems.
I love the Munter. However at times it is better to use an ATC or similar device instead. No twist of rope.