Butterfly vs eight on a bight

[austinconrad]

I've been told by several expereinced climbers to use the butterfly knot for tying in to the middle of a rope (for multi-pitch climbing with three people for example) instead of an eight on a bight. This also seems to be what most books such as "freedom of the hills" suggest. I'm just wondering what advantage a buttefly knot has over an eight on a bight?

[Greg]

The alpine butterfly is designed to be loaded in three directions and does not tend to roll like the 8 on a bight will. If you know you are going to be multi pitching with two seconds I would recommend using two ropes. I think that is a better solution than having two climbers tied in to the same rope because if the climber at the end of the rope falls he will affect the climber tied in to the middle.

[PeterA]

The general reason that the alpine butterfly is preferred is because it is a better knot for bi-directional loading. This is only really important if you have multiple seconds climbing simultaneously. If you are pitching a route out traditionally and bringing your seconds up one at a time, a figure eight on a bight will work fine as it can only see loading in one direction anyway. If you are simul-climbing or there is possibility that the knot will see loading in two directions then the butterfly will be a better choice.

-PJ

[austinconrad]

Cool! thanks for the info guys

[brentc]

An inline figure 8 is another option and works better for bidirectional loading than a figure 8 on a bite. I would guess the alpine butter fly is easier to untie after loading. When I am climbing with two seconds on multi pitch with pitches under half a rope length. I like to have the seconds tie in to the ends of the rope and I tie into the middle as the lead climber. The climbers are then each on a single strand like a normal top rope and be clove hitched into the anchor and positioned on the belay ledge easily.

[austinconrad]

An inline figure 8 is another option and works better for bidirectional loading than a figure 8 on a bite. I would guess the alpine butter fly is easier to untie after loading. When I am climbing with two seconds on multi pitch with pitches under half a rope length. I like to have the seconds tie in to the ends of the rope and I tie into the middle as the lead climber. The climbers are then each on a single strand like a normal top rope and be clove hitched into the anchor and positioned on the belay ledge easily.

So then when you're tied into the middle of the rope and leading the pitch one of the seconds belays you on one half of the rope and the other end drag up with you? I can see how that would make it easier to tie the seconds into the anchor and position them. The first mutli pitch I seconded on the leader had me tie in with the rope and I've done so ever since (wayyy easier).

The alpine butterfly is designed to be loaded in three directions and does not tend to roll like the 8 on a bight will. If you know you are going to be multi pitching with two seconds I would recommend using two ropes. I think that is a better solution than having two climbers tied in to the same rope because if the climber at the end of the rope falls he will affect the climber tied in to the middle.

Makes sense although I think most pitches in NB are less than 30 meters and the first "second" can reach the anchor before they begin pulling the second "second" off the ground. I like the two ropes idea though. With an autoblock type device the two seconds could climb at the same time, which would speed thigns up.

[brentc]

I always anchor with the rope and only clip in with a personal anchor system when required during a multi-pitch rappel. Many times I stay clove hitched into the anchor and lower my second to the ground if conditions permit. I have them untie and I pull their rope end up thread the anchor, knot, coil and toss. I then put myself on rappel with an auto and then disassemble the anchor and descend. I can remain tied in until I am at the next anchor and the end tied to me won't get stuck. I am not sure what the AMGA or ACMG accepted method would be for a leader to tie into the middle. I have tied in before but can't recall the knot. I have also clipped in but I suspect that is not text book. I would only tie into the middle on routes that were well with in my ability as it is a bit bulky and heavy.

[cory]

A few years back, Petzl recommended girth hitching (!) a long looped figure 8 for long pitches with one rope when 2 climbers would simul-climb. Basically tie a figure 8 on a bight that leaves about an arms length loop. Thread the bight through your belay loop, up over your head, then down to the ground. Step over it and cinch the bight into a tight clove hitch around the belay loop. Of course this technique has a few limitations to go along with the advantages.

Advantages: 1)The biggest is that should the third climber fall, the middle climber doesn't get yanked off the wall. The tension in the rope runs from the top to the third climber, with the bight slack to the middle climber. There is no way the knot can invert (and undo) itself what with the bight being so big and having a human attached to it, so that's not a concern.
2)The third climber can be kept under relative tension as the belayer takes in the slack. Meanwhile the middle climber can climb at their own pace, since there is about 2m of play provided by their bight.
3) Everyone can tie an 8, whereas a butterfly is less common (though really simple).

Disadvantages: 1) The middle climber exiting from the bight in (order to set up a rappel) is a challenge especially on a crowded or hanging belay. This could probably be resolved by using a pair of lockers rather than the girth hitch though there is probably some disadvantage to having lockers freely slide around a loop (cross loading, for example).
2) It takes some practice to find the optimal bight size. Too big and the knot gets stuck on gear that's beyond reach, too small and it's really awkward to work it around your body to tie the girth hitch.
3) It takes up more rope. But then again, if you're in a party of 3 with only one rope, you're not going to attempt 60m pitches are you?

Questions:
Any reason why you can't tie a butterfly leaving a long loop?
There is plenty of strength left in a rope and a wide triple layer belay loop after girth hitching, but what about a thin belay loop and skinny rope?
Any reason why you can't use a couple lockers in place of the girth hitch?

[cory]

Oh yeah, one more advantage of the 8 is that it's easier to untie once loaded in a fall compared to a butterfly, and less prone to loosening itself when slack. And another disadvantage is loosening the girth hitch can be a bit difficult.