documented info on why gyms require you to back up a figure eight using an overhand

I was told the same thing by management for the Planet Granite gyms (who probably collaborated with Sender One) -- the backup knot made for easy and repeatable visual inspection by staff, to ensure enough tail.

Does anyone have a copy of the Climbing Wall Association's "Industry Practices, Sourcebook For The Operation Of Manufactured Climbing Walls" that can report on whether it addresses backup knots? The Commonwealth of Massachusetts references it as a standard (520 Mass. Reg. 5.01).  And a California court cited it in affirming dismissal of a suit against Hanger 18, albeit with respect to orientation procedures and bouldering.  (Tan v. Hangar 18 Indoor Climbing Gym LLC, No. E067759 (Cal. Ct. App. Oct. 9, 2018)).

I understand it to be a “finish knot”, not a “backup knot”.

It’s tied simply to ensure there is enough tail. 

aaronhand wrote:

I was told the same thing by management for the Planet Granite gyms (who probably collaborated with Sender One) -- the backup knot made for easy and repeatable visual inspection by staff, to ensure enough tail.

PG in Portland used to be incredibly strict about using a double overhand finish. A few years ago I tied in to help my friend take his lead test, but I misjudged the amount of rope slightly. Since I had some extra I just finished it with a triple overhand instead of a double so I didn't have a hanging tail, but the employee testing him made me redo my knot with a double overhand.

Earlier this year I heard from staff that the double overhand finish isn't required anymore, so I wonder what changed to allow them to be more relaxed now.

Steve Mcgee AZ & the University of Canada need to reprove that, cause you are wrong. A short tail on a figure of 8 can back its self out. I've seen it happen, it may be rare but it has happened!

The Tan case is pretty interesting reading:

https://casetext.com/case/tan-v-hangar-18-indoor-climbing-gym-llc?resultsNav=false

Tan went to Hangar 18 in Upland, had never climbed before, and fell off the bouldering wall and injured her spine. She claimed there was an industry standard of one inch of padding under the mat for every foot of height of the climbing wall, which would have been 14", but when her lawyers hired someone to go and check, they found only 8". She also claimed that the gym was bad because they didn't train her in how to fall safely. In a deposition, a Hangar 18 employee said, "There is no good way to fall." Her case got dismissed, and she also appealed but lost. The court awarded costs to the gym.

Ben Crowell wrote:

Cool, thanks for posting. This was exactly what I was hoping for -- actual evidence about why gyms require it, as opposed to speculation. So it's actually kind of a hybrid of two of the hypotheses earlier discussed. It's about visibility, but not visibility of a long enough tail.

Were you influenced by having worked at some other gym that did this with the same rationale?

This would explain the inconsistency with the AMGA SPI manual. That book is written for guides who are going to be closely supervising a small number of clients, not for gym employees supervising a mob of climbers.

I'm trying to imagine what knot someone could tie that they thought was a rewoven figure eight but actually wasn't a knot. I did hear a story about someone at SO who simply didn't tie in before he started a lead, and he had earbuds in, so he couldn't hear his belayer yelling at him that the rope had fallen out of his tie-in loops and was on the floor. The story was that once he realized it, he started downclimbing, then inexplicably jumped off from high up rather than finishing the downclimb, and got hurt.

Did he just think he'd tied the figure eight, but hadn't really tied a knot at all? And then he tied the overhand to back up the nonexistent knot?

Or was he at a gym, where someone had left a figure eight tied on a toprope setup, and he never did the step of completing the figure eight, but he tied the overhand?

Tradiban is exactly right.  Newer climbers don't always tighten their figure-eight knot and rarely get enough tail at the end of it.  The barrel knot at the end forces them to get enough tail.  The figure-eight is a self-tightening knot but without enough tail, it could (?, never seen it happen) come undone.

The knot-tying rules do vary between gyms. I think Touchstone only requires 6" of the tail. My home gym in Virginia required some kind of finishing knot (e.g., Barrel Knot, Overhand, or Yosemite Finish).

Ultimately, if there is a chance to make something safer why not do it? Tying a barrel knot on the end is like using a prusik for a rappel. 5 seconds and things are safer.
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There is a way to tie the figure-eight knot to where it looks correct from one angle and incorrect from another angle. Once I remember how to do it I'll share it in this comment.

Edit:  Note, when looking for the 5 parallel lines this would still pass the "check" if you're just going through the motions and not actually looking at the knot as well.

I always thought it was just what you do with the leftover rope.
I have heard of a person getting the overhand caught in their mouth and it popped out their front tooth/teeth during a fall, so I stopped using it in favor of the Yosemite finish. None of the gyms I go to have ever complained but they all at least teach the overhand. I have no idea if it's an actual requirement though.
They have asked my partner not to use the bowline follow through to tie in, stating that they don't want anyone trying copy it and failing. And there is no way for the staff to know if the belayer knows how to doublecheck that knot. 

Mark Frumkin wrote:

Steve Mcgee AZ & the University of Canada need to reprove that, cause you are wrong. A short tail on a figure of 8 can back its self out. I've seen it happen, it may be rare but it has happened!

It has happened to me, once. Or, at least, I believe that is what happened.

I tied in with a figure 8, with a short tail, maybe ~2 inches. But I thought it was long enough. Both my belayer, and myself, believe that I had finished tying the knot, it wasn’t a case of getting distracted and not finishing the knot. I wasn’t wearing a bulky shirt, just a tank top, the belayer saw me tying the knot; I never pause mid-tying, and there was absolutely nothing going on to distract me— no people, no interesting conversations. We did a pre-climb check, and both believed that the knot was properly tied. But when I arrived at the anchor of (admittedly longish, 30+ meter) single-pitch route, the last follow-through strand has worked itself out of the knot, so the knot was partially untied, just the very last part of the figure 8. I do think it would have held a fall. But I’m glad I didn’t test it. 

I do now leave a longer tail.

It used to be common, but is now being phased out due to increasing numbers of SPI and higher guides telling people that it is not needed.

Just make sure that you have a proper tie in knot. Through both points, tied correctly, set enough, enough tail. That is it. Dressed is nice but not necessary.

Lena chita wrote:

I tied in with a figure 8, with a short tail, maybe ~2 inches.

A pretty standard rule of thumb for knots is that the tail should be double the diameter of the knot. When I'm teaching people to tie in, I always demonstrate how to measure the amount of rope by holding it up to some standard point on your body. That way you know you're going to end up with the right amount of tail. On my body, the location is around my sternum.

I went to a gym that bans all backup knots as well 

Ben Crowell wrote:

 When I'm teaching people to tie in, I always demonstrate how to measure the amount of rope by holding it up to some standard point on your body. That way you know you're going to end up with the right amount of tail. On my body, the location is around my sternum.

That only works if you're always using a rope of about the same thickness.  I generally like fat singles, which nowadays tends to mean 9.8mm; if I grab the same body-point of rope to tie in with one of my 7.8 twin/half ropes, I'm going to end up with almost enough tail to do another whole tie-in.

The real reason that everyone started using figure 8 overhand backups is because bowline tie ins kept failing.  

Back when, @1973-75, more people tied in with bowlines than with figure 8s. I'd say around here it was @60-40%, perhaps more. Bowlines can become untied simply from slight moments and after there were multiple deaths from properly tied bowlines that became untied while the climber was climbing, the backup knot became the norm for the bowline tie in. Some people bailed on the bowline and started doing the figure 8, and they brought the backup knot with them. At some point it was learned that even with a backup knot, a bowline can become untied all on it's own and after a fatality or so - no one was using the bowline except for a few hardcores who modified it a bit to make it not untie.  

An alternative to the overhand finish, which as noted has no value, is the "Yosemite Finish" on the figure 8. The rope is followed back through so that the tail end is tucked back into the knot and points towards the climber instead of out and there is a loop available to grab. This innovation allegedly came about because Ron Olevesky use to do that follow through to tie off his mules. The mules tugging and pulling always cinched the figure 8 knot down super tight and Ron used that finish to be able to better untie the knot. He showed Bridwell and Bridwell used it and shared it and it became known as the Yosemite finish as it was so common there. 

If you are a heavy climber and dogging a route, a better way is to simply wrap an extra turn around the tie in point and tie the regular figure 8, it will be easier to untie. 

Regards

Haven't seen anyone else mention that if the tail pulls through the 8, it is still an inline figure 9, and shouldn't fail under load. 

Super cool history Billcoe!

Billcoe wrote:

The real reason that everyone started using figure 8 overhand backups is because bowline tie ins kept failing.  

Rethreaded bowline, aka bowline on a bight is extremely safe. Quite a few European climbers use it.
Here are instructions with proper non-American accent -
https://www.youtube.com/watch?v=1uo_Ohq_gVg

One thing needs to be emphasized - there are many variations of bowline, quite a few ways to make it very reliable. Unfortunately, it is not easy to inspect. 

Fig8 is strong, it is easy to teach, everyone knows how to tie it, everyone knows how to inspect it. It is the lowest common denominator of the climbing world, and gyms recognize it.

It makes it easy to see that there is sufficient tail from a distance (the desk).

Jay Anderson wrote:

It makes it easy to see that there is sufficient tail from a distance (the desk).

Yes but a tail will not backup an improperly tied fig 8.

Billcoe wrote:

If you are a heavy climber and dogging a route, a better way is to simply wrap an extra turn around the tie in point and tie the regular figure 8, it will be easier to untie. 

Interested in this, but can't quite figure out what it means? Is there a pic of what you're describing that you can point me to? 

In Sweden it not by the norm to use a back-up knot and you would probably not pass the belay test if using it. It is just considered something that pose the risk of catching on something and is a sign that you have not tied a figure-8 with a tail of proper length tail (at least ten times the diameter of the rope, and not so long that you could clip it by mistake or get whipped in the eye by the tail). It also makes the figure-8 harder to inspect if you have extra knots after it. 

Wictor Dahlström wrote:

In Sweden it not by the norm to use a back-up knot and you would probably not pass the belay test if using it. It is just considered something that pose the risk of catching on something and is a sign that you have not tied a figure-8 with a tail of proper length tail (at least ten times the diameter of the rope, and not so long that you could clip it by mistake or get whipped in the eye by the tail). It also makes the figure-8 harder to inspect if you have extra knots after it. 

- mistaking the tail on your knot as the climbing rope

- losing an eye because you get hit with the tail of your tie-in knot

- being confused by the extra knot on the tail

That is how you take YGD to the next level