How should I cut my rope?

[wellyjen]

Re. Passing knots - plenty of times you can (with planning, rather than finding yourself accidentally 10m off the deck) use the additional rope for the traverse so no knot pass is needed. Max length of rope between two anchors would be a useful variable to know

It really would. Unfortunately, the data doesn't exist. It all comes from existing topos, drawn up over several decades and rope lengths used between anchors wasn't something that was recorded. The rope lengths given in topos are often arbitrary on multi pitch shafts and as likely to be where the person on the topo drawing trip happened to pick the next rope out of the tackle bag at a rebelay as any other consideration. Given that limitation, Ari's tool is rather clever. Sometimes topos will include pitch lengths between rebelays and with suitable allowances for rope loops, knots, Y hangs and so on, then you can estimate what length will likely work to an intermediate anchor from the topo.
As for passing knots mid pitch, I'll only rig like that if it is absolutely required and I know every one on the trip can cope. If some one has only just learnt SRT and has done a couple of practice knot passes in a barn, there is a good chance they'll struggle with one in a cave and I'll change the cave, rather than include a knot pass. With a bit more general SRT experience, a first time underground knot pass is less likely to turn in to an epic.

 

[wellyjen]

A recent example of topos where the intermediate rope lengths in multi-pitch shafts are given are the ones for Longcliffe Mine, prepared by the DCA. It explicitly shows the option of either using two long ropes of 38 and 35m, or six short ropes of 12, 13, 3, 10, ,22 and 14m. This is all the info you need to work out any combination in between to suit the caving string you have available, where all the rope joins are at anchors and not mid-rope. The rope lengths need to be measured in greater detail after derigging to give this, but it is an excellent model to follow.

 

[pwhole]

I guess we should pull ours out at some point then, so folks can try it. But there's still plenty of work to do, so maybe not yet

 

[Tseralo]

I have this graph driven from the TSG tackle spreadsheet which I use to decide what to cut next. Generally, it's just what's coming out of service after 10 years and do we have enough in the 60-90 category. No ones complained yet.

 

[cap n chris]

9 year old rope. I'd be very interested to see what that looks like on a close up photo!

 

[alastairgott]

It’s probably our trusty 10.5mm Beal. I used to pull them out every now and again for an entrance shaft, as the weight doesn’t matter so much. But I think the bigun is largely less well travelled now 9mm are in good supply.

Can’t say the same for the shorty 2014’s though, I think they get thrown around quite a bit.

 

[Tseralo]

9 year old rope. I'd be very interested to see what that looks like on a close up photo!

Most of them are in good condition, or I would have binned them. Its time for six monthly inspections again, so I'm currently sorting all the sheets.

Some of the ones that didn't make the cut at the last one are now with our tame CIC for his inspection courses.

 

[cap n chris]

Most of them are in good condition, or I would have binned them. Its time for six monthly inspections again, so I'm currently sorting all the sheets.

Some of the ones that didn't make the cut at the last one are now with our tame CIC for his inspection courses.

I'd still be interested to see a picture of them close up; our work ropes (generally, in peak season) get condemned after about 5-10 days of use (properly hammered: admittedly that was after lockdown(s) when our demand increased by about 400% versus a normal trading year with backlogs etc.), if it's low season they might last a few weeks before being worn out; it would be helpful to see what ropes (which are many years old) look like by comparison. We bin in excess of a Km of rope each season, actually probably a lot more than that. There's a log obviously but I'm at home currently so can't check it for a precise figure.

 

[Tseralo]

I'd still be interested to see a picture of them close up; our work ropes (generally, in peak season) get condemned after about 5-10 days of use (properly hammered: admittedly that was after lockdown(s) when our demand increased by about 400% versus a normal trading year with backlogs etc.), if it's low season they might last a few weeks before being worn out; it would be helpful to see what ropes (which are many years old) look like by comparison. We bin in excess of a Km of rope each season, actually probably a lot more than that. There's a log obviously but I'm at home currently so can't check it for a precise figure.

When your up our way next, your are welcome to come to have a leaf through the tackle store. Currently we have 1136m of rope total and add a 200m drum a year (180m after shrinkage). Of which 917m is 9mm Gleistein Geostatic and the 10.5mm. It's a really different use case to you guys as well. Our wear is spread across all the ropes, they are only used a few times a week max, all the users are experienced, and the ropes are always soaked and thoroughly washed after use.

I'm pretty enthusiastic when it comes to condemning equipment as well. I try not to look to hard at some of the other tackle stores I have access to or id never use them.

 

[mikem]

Depending on how they are racked and what size they are, some club ropes hardly ever get used

 

[Tseralo]

Depending on how they are racked and what size they are, some club ropes hardly ever get used

Yeah, I can't check the logs at the moment, but TSG seems to use either 20s or 60s and 70s. The two 90s hardly come out as the few pitches that need them are hard-rigged by members anyway.

 

[andrewmcleod]

The BEC SRT ropes (used to be 10.5mm and 11mm I think) were still in very good nick when they hit 10 years old. Of course they didn't get used that much...

I retired some of the rope lurking around in the darker depths of our exped store after cutting a bit off to look at the marker tape and finding in was made in the 90s... Bet it was still safe enough though (chunky old rope)

 

[mikem]

The tool can't quite handle 2x 175m ropes at 5m resolution (p(175/5) is 14883, and 14883² is 221.5 million possible combinations for the tool to test), but 2x 180m ropes at 10m resolution gives:

Cut lengths	Possible trips (of 292)	Efficiency
[[90,50,40],[60,40,30,20,20,10]]	272	0.811
[[60,50,40,30],[90,30,20,20,10,10]]	270	0.827
[[60,50,40,30],[80,30,20,20,10,10,10]]	267	0.832
[[60,50,40,30],[70,30,20,20,20,10,10]]	265	0.833
[[60,50,40,30],[60,30,20,20,20,10,10,10]]	257	0.836
[[70,50,30,30],[40,40,20,20,20,10,10,10,10]]	255	0.839
[[60,40,30,30,20],[50,50,20,20,10,10,10,10]]	251	0.842

This would be Elliot's:

Cut lengths	Possible trips (of 292)	Efficiency
[10,10,15,15,20,20,25,25,30,30,40,50,60]	245	0.892

Can it kick out which trips you are gaining / losing?

 

[aricooperdavis]

Can it kick out which trips you are gaining / losing?

This would be fairly straightforward. I'll have a think about how that information could be presented.

For the time being maybe pair it with the original "What can I rig?" to work out the possible trips for different rope combinations?

 

[Tangent_tracker]

This is brilliant. The way I have previously done this is to list all the common trips in a certain area and then manually decide how to split rope to better make use of rope. Takes some time to go through the combinations!

 

[mikem]

It is, but, in its current state, you may end up with a load of ropes only suitable for trips that nobody wants to do. So critical thinking still required.

Where there's 272 out of 292, then it's fairly easy to list the missing 20 trips, but do you want to be listing 50+ for Elliott's selection?

 

[wellyjen]

It is, but, in its current state, you may end up with a load of ropes only suitable for trips that nobody wants to do. So critical thinking still required.

Where there's 272 out of 292, then it's fairly easy to list the missing 20 trips, but do you want to be listing 50+ for Elliott's selection?

Plug the recommended cut lengths in to "What can I Rig?" and see if the trips you actually want to do are in the list. If it is coming up with a list including Grotty Pot, Slime Mine and Mud Pit, but not Sparklycrystal Cavern, or Awesome Pot*, then you need to adjust.
Jen

*Names may possibly be made up. If so, feel free to use them on your next discovery.

 

[Ian P]

All this sounds over the top and complicated.

Why can’t you just ask ChatGPT 🤷‍♂️😂

 

[wormster]

The BEC SRT ropes (used to be 10.5mm and 11mm I think) were still in very good nick when they hit 10 years old. Of course they didn't get used that much...

I retired some of the rope lurking around in the darker depths of our exped store after cutting a bit off to look at the marker tape and finding in was made in the 90s... Bet it was still safe enough though (chunky old rope)

Yes that was good rope when I bought it into service, good to hear it's still around.

BTW: I use a hot knife to cut ropes, seals the ends of neatly.

 

[MarkS]

All this sounds over the top and complicated.

Why can’t you just ask ChatGPT 🤷‍♂️😂

I asked it "What are the best rope lengths for SRT caves in the Yorkshire Dales assuming I start with 300 m?", to which it replied a load of waffle, so I followed it up with, "Please just list a sensible set of rope lengths that sum to 300 m".

Why did you bother with all that code, Ari?!