'biner block

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[edit] Intro

A Carabiner Block (aka 'biner block) is a simple way of blocking off a rappel. The main idea behind the 'biner block is to attach the rope to something strong that won't pass through the rap-ring, and still provide a way to pull the rope. By "Something strong" we mean something rated - like a carabiner. If you are fresh out of carabiners, you can use a Knot Block by tying a figure-eight on a bight - but knot blocks can get stuck in the rappel rings, and in some cases can pull through (as knots get smaller as you pull on them). The rap-ring or rapide must be small enough that the carabiner cannot ever pass through it. A death occurred in Heaps canyon when a 'biner block against a pear-shaped carabiner pulled through.

A 'biner block is especially useful to fix a specific distance of rappel line when rappelling into a swimming disconnect. Using the 'biner block, one can position the end of the rope just below the water line and rappel right off it. This avoids the danger of disconnecting while treading water and dropping the rappel device.

A 'biner block is commonly used in conjunction with a rope bag. With a rope bag, one can pay out only enough rope needed for the drop without needing to uncoil the entire rope. See rope bag page for details.

'Biner blocks are very useful in moving water. They allow the canyoneer to descend single stranded, which avoids the possibility of tangling the two strands together in a current. Typically a contingency anchor is set for all but the last canyoneer. This way, if someone is caught in a hydraulic, canyoneers from above can quickly lower them.

'Biner blocks are also a useful way to extend a short rope. If you have one rope long enough for the rappel, but not enough to retrieve the rope, set the rope for rappel, fix a 'biner block and then tie everything you can find (extra webbing, shoe laces, back packs, etc, etc) to the retrieval end of the rope. Rappel and then pull the rope with your conglomerate line.

For those with more guts than brains you could lighten your load with a 'biner block. If there is no drop on a trip longer than 100' in a canyon, you could carry a 100' rope and a light weight 100' pull line. This saves you the weight of a second rope. More realistically, you should probably bring the second rope as a back-up, in case your beta isn't up to snuff or your rope gets stuck.

• It should be noted that there have been a few falls in Zion by canyoneers using some form of a block that failed. One of these falls was lethal. It appears that failure has occured both with a 'biner block that pulled through a large anchor rapide and by people rappelling single stranded on the "pull side." Rappeling single strand on a block has its place, but if you can rap double stranded it is much harder for the system to fail. If you do rap single strand on a block, consider keeping the "pull line" coiled on top of the rappel for all but the last rappeller. This way everyone clips into the correct strand. Or, after setting up your block, tie off the rappel rope to the anchor for all but the last person. Hopefully the final - typically most experienced canyoneer - doesn't foul up their rappel.

[edit] How to set up a 'biner block

Be sure you have enough rope to properly retrieve your rope... Unless you like leaving ropes in canyons

How to tie a Clove Hitch

1. Secure yourself to the anchor by clipping into the anchor.
2. Run one of the ropes through the rap ring or rapide.
3. Lower that end of the rope until it goes as far as you want it to.
   • If you are rappeling into water, you may want to have the rope just barely above the water to eliminate the need to unclip under water.
4. Tie a Clove Hitch around the spine of a locking carabiner and cinch it tight.
5. Tug against the clove-hitched-'biner against the rap ring to make sure that the 'biner won't pass through the anchor. The rap ring or rapide must be small enough that the clove-hitched carabineer cannot ever wriggle through it.
6. Send the group down single stranded.
7. The last person has two options:
   • Toss the rope bag and rappel single stranded
   • Clip the rope bag to their harness and pay out the retrieval line as they rappel single stranded.

[edit] How to pull the rope

1. Pull on the side that wasn't blocked by the 'biner

[edit] Using a 'biner block and a pull line

'Biner block: Rappel on the right line, pull the left. A locking 'biner is more secure and more commonly used than the Oval 'biner shown.

Using an overhand knot on a bight locked off with a carabiner. Rappel right, pull left. Clip the 'biner to the anchor for safety until the last rappeller goes. Clip as shown to enable rope retrieval. Make sure the knot will not get stuck in the rappel ring, and that the knot, even when tightened, will not pull-through the rappel ring.

A 'biner block is useful when you'd like to use a pull-line.

1. Set your anchor as usual.
2. Run the rappel line through the rapide. Don't drop it! (Probably is a good idea to tie a quick figure-8 on a bight and clip the rope to the anchor before monkeying with the next details).
3. Tie the rappel line in to the lighter pull line with your favorite knot (double overhand with long tails, square knot with grapevine ends, reverse double fisherman, etc).
4. Prevent the knot from sliding through the rapide by tying a clove hitch on the spine of a carabineer. (As above, make sure it cannot ever slide through the anchor before rappelling).
5. For security, clip the rope to the anchor until the last rappeller.
6. Throw the rappel line down.
7. Everyone rappels off the rappel line
8. Pull the pull line. The rappel line should travel up to the anchor and back down to you.

• Alternatively, replace the clove hitch with a figure-8 or overhand knot on a bight locked off with a carabineer.

[edit] Caution

When using a 'biner block, you rappel on a single line. This has much less friction than a double-strand rappel. Be careful, especially with a thin, static line. There have been accidents as rappellers have lost control when the single line rappel had less friction than they expected! Consider using a belay or tying a backup prusik.

The advantage of the double-stranded rappel over the 'biner block is that there is less to snag on the pull. When pulling the rope with a 'biner block, be careful not get the carabiner caught on a crack or a bush on the way down.

When pulling a 'biner block, remember that the knot will expose the rope to constant abrasion. If you have a long pull across rock or canyon, the rope in the knot can be injured as it is dragged across the ground. This can be avoided by tying the block through a Gatorade bottle (cut the bottom off), or by not using the block. If you need to rappel single stranded from an upstream anchor (say you are rappelling into a hydraulic), you can fix the two strands close to the spill-off with a stein knot for the first rappeller. Once down, the first rappeller ties into the pull line and the second rappeller can go single stranded, counter balanced against the first.

[edit] Avoiding rope tangles using a 'biner block and rope bag

It is common for canyons to contain multiple short rappels (say 30-40 feet) as well as longer rappels that require a full rope length (100-200 feet). This means the canyoneer will need to recoil a full-length rope after every drop, even though most of the drops are short. One can either carry a separate short rope for the short drops or use a 'biner block in conjunction with a rope bag. This combination has revolutionized canyon rope management. It allows quick deployment of only the rope needed for the drop without tangling the whole mess.

1. Take one end of rope and run it through the rapide.
2. Pull out enough rope to reach the bottom. (If you can't see or hear the rope touch the bottom, set a contingency anchor).
3. Block that end with either a 'biner block or a knot block.
4. Throw down the rope bag with the rest of the rope (should deploy smoothly).
5. Rappel either single or double stranded (if single stranded, be sure to rappel on the blocked strand!).
6. Once down, pull the un-blocked end and stuff the rope back in the rope bag.
7. Voila , no tangle, no hassle.

[edit] Links

• Using a Figure 8 to isolate two rappel strands. This is a useful technique to speed a group down a drop. A canyoneer can rappel on one strand, while a second sets up to rappel on the other.
• A Figure 8 on a bight block can be similarly used. By securing the figure 8 knot to the anchor with a locking carabiner one can isolate the two strands allowing a group of canyoneers to quickly rappel down the strands independently. See Petzl for details and diagrams. One should take care with this technique as this isolates the entire anchor on a single point with a second point as an unweighted backup. Should the first point fail, the second will need to hold significant impact force when the rope draws taught, especially if there are two canyoneers on rappel simultaneously. Also, by weighting the figure-8 on a bight, some poor canyoneer will have the difficult task of untying this knot.
• ACA forum discussion on setting rope length and knot blocks.
• Tom's Utah Guide also has some pictures and alternative back-ups for the block that are well worth seeing.
• Bogley discussion with nice pictures.

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