Rigging a Fixed Scaffold bar

[JWright]

What knot would you use to rig to a fixed scaffold bar?
The kind of situation I am thinking is like at the top of Hillocks climbing shaft (if you know what that looks like) 

[T pot 2]

Tie half a figure of eight put the none load end over the scaff bar and back thread the half tied knot.
If you leave enough of a tail in the rope you could do the same for a back up on the bar too.

[wellyjen]

I'd always have it backed up to something if at all possible. As much to provide a loop easy to clip in to protect people on approach than as safety thing if the scaff pole failed. Wrap a short sling round it enough times to get the knot at a satisfactory height. Depends what if anything there is for people to stand on in the shaft where that is. Then, krab in to the ends of the sling and knot in to that. You can tie the climbing rope directly round he scaff bar if it is removable, like at the top of Oxlow, or Eyam Dale House. Nice big radius around the tube. If the tube is fixed, this makes judging how much rope to leave to go to a backup tricky and leads to time wasted adjusting lengths. Slings are cheap, so take one with you. The sling wound round the tube will also keep it in position. There may be parts of the tube that if the suspension point slides along will give a rope rub lower down.
Just what I do.

Jen

[mikem]

Sling if you have one, otherwise clove hitch tied off with half hitches (or a few round turns if you can't remember the clove)

[Brains]

Same method as T Pot

[cavemanmike]

Sling every time

[mikem]

If you don't want the retied figure of 8 to slip, you can use round turns or a clove hitch in the middle.

[pwhole]

I actually did manage to tie a re-threaded figure-9 one night when I was bored, so it is possible. But boring 

[Tseralo]

I prefer to tie a bowline with a long tail that I can backup to another thing or the same scaff bar if there isn't anything else IE JH. Some of our members seem to dislike this as its a bit more faff to remove when its blowing a gale and prefer a sling and crab. Personally I would rather reduce the amount of failure points in the system.

[mikem]

If they are happier with a sling & krab, than that is better than them tying a bowline wrongly. The only place it is more of a risk is where someone else might comes along & remove it.

[paul]

Also a sling and krab makes the knot lower than tying directly into the scaffold bar making it more difficult to get on or off the rope in some cases. Why add more gear when you can tie he rope directly to the scaffold bar and use the tail to tie to a back-up or nearby anchor?

[MarkS]

I prefer to tie a bowline with a long tail that I can backup to another thing or the same scaff bar if there isn't anything else

Is a backup really a backup if it is attached to the same thing?

[Tseralo]

I prefer to tie a bowline with a long tail that I can backup to another thing or the same scaff bar if there isn't anything else

Is a backup really a backup if it is attached to the same thing?

It’s the same reason we teach people to backup their fig 8 with a stopper in climbing.

In reality if the first knot is tied correctly it’s not needed but people talking to you, being a bit excited to get underground or just keen to get out of the wind can distract people. Sadly this has killed people climbing including a friend of a friend quite recently.

[Brains]

Re-threaded fig 8 with a tail to a backup stake, note how little gap is between the bar and usable rope for descent

[Fishes]

A wrapped sling or bowline. A rethreaded figure of 8 is good but can be a real pain in the ass to undo sometimes.

[nearlywhite]

I actually did manage to tie a re-threaded figure-9 one night when I was bored, so it is possible. But boring 

I use them fairly often. And would use it in this situation

Rethreading a bunny ears when someone you don't like is derigging is more of a challenge.

[PeteHall]

Rethreading a bunny ears when someone you don't like is derigging is more of a challenge.

As long as it's not your rope, otherwise they might be tempted to just cut it off 

[A_Northerner]

Rethreading a bunny ears when someone you don't like is derigging is more of a challenge.

As long as it's not your rope, otherwise they might be tempted to just cut it off 

I recall a derigging trip down Oxlow with Rostam in my first year where I had to de-rig a re-threaded figure of eight bunny ears in new 9mm rope that had just been weighted by Rostam - it was DCC rope as well so not ours to cut! After 30-45 minutes I finally got it undone, and he then revealed to me that he hadn't brought any tackle bags.

We're not known for treating novices kindly in SUSS...

[nearlywhite]

I had to de-rig a re-threaded figure of eight bunny ears in new 9mm rope that had just been weighted by Rostam

it had been weighted by 6 other people... cheeky sod. Also for the record I had assumed the tackle sacks were hung up as they'd used them... nope they'd taken them out. I do think of that trip most times I'm on that hillside.

[Fulk]

Fed up with struggling to untie recalcitrant knots, last year I bought a marlin spike – though admiitedly it wouldn't be much use for untying rethreaded knots underground.

[Bob Mehew]

This question did raise in my mind how one might quantify the difference between knots.  Work by Lyon Ltd indicates most knots have a similar level of reducing the strength of a rope, so the next step would be to look at the ease of tying and untying it after loading.  Any ideas on quantifying the difficulty of untying a loaded knot?

[pwhole]

Measuring the swollen lump on the right thumb knuckle two days later is my usual method

I must say I'm now almost fired up for trying that re-threaded Figure 9 again

[Mike Hopley]

Any ideas on quantifying the difficulty of untying a loaded knot?

I suggest measuring it in swear words per minute per fresher.

...Is that a laden or unladen fresher?

[Tseralo]

This question did raise in my mind how one might quantify the difference between knots.  Work by Lyon Ltd indicates most knots have a similar level of reducing the strength of a rope, so the next step would be to look at the ease of tying and untying it after loading.  Any ideas on quantifying the difficulty of untying a loaded knot?

How many times I have to hit it on the floor?


Sent from my iPhone using Tapatalk

[Mike Hopley]

Okay, serious answer:

Time taken for the same person to untie the knot. Repeat across different knots, and different rope diameters, and multiple people. Average results from all different people to get time for a given knot, at a given diameter.

Probably standardise the knot tightening, say 100kg, slow pull, for 5 minutes. You'd also need to decide whether any "tools" are allowed, like carabiner noses or spanners.

To get any meaningful results, you would need a lot of data. I expect you'd find that thin ropes drastically exaggerate the differences between knots.

In 8.5 mm or lower, I've stopped using figure-8 loops at single-bolt rebelays, as they are a bastard to untie. Bowline-on-the bight is a lot easier. Alpine Butterfly is easy, and Fusion is easy.

Maybe the sneaky way to get your data would be to turn it into a new competition at Hidden Earth!

[Fulk]

In 8.5 mm or lower, I've stopped using figure-8 loops at single-bolt rebelays, as they are a bastard to untie. Bowline-on-the bight is a lot easier.

Agreed, Mike – except I'd say ≤9 mm; in fact I had to use the marlin spike on a figure-of-8 knot in 10.5-mm rope last Sunday after a little trip down Death's Head Hole.

[Mike Hopley]

Agreed, Mike – except I'd say ≤9 mm; in fact I had to use the marlin spike on a figure-of-8 knot in 10.5-mm rope last Sunday after a little trip down Death's Head Hole.

Actually yes, now that I've gotten comfortable with them I'd rather just use BOTB for all my single-hang needs, even in thick rope. I like making life easy.

[Fishes]

I have mainly caved in Derbyshire so ropes need washing pretty much every time. I found that if I left the knots in the rope where possible that they were then so loose after coming out of the washing machine that the pretty much fell apart when inspecting and repacking the rope.

[Fulk]

Oh! That's interesting, Fishes, I've always untied knots before washing ropes – I've never put a rope in the washing machine with knots in it.

[PeteHall]

...after coming out of the washing machine...

I've never put a rope in the washing machine with knots in it.

I've never put a rope in the washing machine, ever! The risk of domestic fallout surely outweighs any time saved 

[Fulk]

I've never put a rope in the washing machine, ever! The risk of domestic fallout surely outweighs any time saved 

You should have married a caver.  (In fact, in my experience ropes come out cleaner from a washing machine than they do from a conventional 'rope-washer'.)

[Fishes]

I've never put a rope in the washing machine, ever! The risk of domestic fallout surely outweighs any time saved 
[/quote]

You need to get your priorities sorted :-) My partner also puts caving gear through the washing machine.

I had to stop her putting carabiners etc in the dishwasher too. They come out nice and shiny but hot sodium polyphosphate solutions aren't great for aluminium alloys.