Tech Tip: Question Additional blocks when joining ropes?

When joining two ropes for a rappel, do you use the joining knot as the block, or do you add an additional block if rappelling a single strand?

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I was watching a canyoneering video and noticed a carabiner block a foot away from a double EDK that joined two ropes. I would have assumed that people just used the joining knot as a knot block. It is possible that the particular knot/rope combo would not have worked as a block, but I'm wondering what is common practice.

As with most things, I would say it depends. If rapping single strand I would lean into using a carabiner block near the EDK. A double EDK doesn't work well as a knot block, due to it's smaller size and tendency to jam into, or slip through the ring. Rigging with a carabiner block and keeping the pull rope up top until the LPAR instead of doubling also gives the benefit of rope being available to perform a rescue if necessary.

In the above scenario it's also possible the EDK would be joining a pull cord or small diameter rope not suitable to rappel on.

Or just use a toggle.

Where is your knot in this scenario? i.e. is it below the anchor so that you can lower the person (assuming you used something like contingency releasable-figure8-block) if get stuck w/o passing the knot through the anchor?

• If so - what knot do you use to connect the ropes...I know figure8 follow through will work, but what about square knot backed up with overhands on each side?
• If not - what do you do in such scenario?

I like to use a knot block and would not add unnecessary redundancy with a biner block unless I was concerned that the knot block was too small for the rapide. I have started to use the double overhand bend for joining ropes. I previously used the stacked EDK until I read this article from Rich's archives. https://canyonsandcrags.com/pdf/which-bend.pdf

The double overhand adds a little bulk for the knot block. This is a plus when one of the ropes is a 6mm pull cord. I also love the toggle and use it in every scenario that is appropriate and timely.

That was my thought as well. Since you're rappelling single strand in this example, it really doesn't matter which knot you use, since it is only used for the pull cord and not body weight. You can pick the biggest, bulkiest knot possible and be confident in the block.

If the flat overhand fails at 7000 kN, doesn't that make it more than adequate? I'm more concerned with the bulk of the knot and its geometry. The flat overhand is amazing how it can slide over rock and not get snagged during the pull. I'm not a fan of a knot block against a ring for the reasons mentioned by Tirrus.

I have no objections to this technique. My only objection is that it fails at 7-8 kilonewtons, not 7000. I agree that 7 kn is very adequate in most scenarios.

Once upon a time, while bringing up a second at a small crag that has a hikeable route nearby to the belay I was at, I had a hiker chat with me for a few minutes and they relayed a story about how they had once been on some sort of adventure with rope and insisted that whoever they were adventuring with "bring out the thousand foot rope." Maybe during the next campfire regaling session I should try to find some way of working a 7000 kN rope into the tale.

Here's my team getting our ropes in order.

Fingers crossed the block doesn't pull through the rapide on this one!

Is that a STATIC rope?
Attire? eagle scouts?
Tib-fib break for the lead guy for sure- "never pull when everyone else is pushing"

Is that the pull cord?

Yea, it used to be 6mm before it got wet. Slight swell.

How descend the last with this tecnic?