Pull-through rope lengths

[langcliffe]

I read on a trip report that a group became confused as they couldn't understand why the route guide they were following on the Magic Roundabout circuit claimed that a "couple of 25 m ropes suffice" for negotiating the 20-metre deep Aquarius Shaft.

For many decades I have taken the stance that if there are a number of experienced people in a party, the carrying load would be distributed amongst them. In this case, 50 metres of rope is required, so two people take a 25 metre rope each.

At the top of the shaft, the full length of the first rope would be used to descend the pitch, and the last person is expected to tie on the pull-down rope, and descend with that.

I would be interested to know whether this is the normal approach, or whether people really do lug a 60 metre rope down Simpson Pot to descend from the top of the Slit.

 

[mikem]

Suggests that they were expecting to do two shorter abseils. People do both, depending on what they have available (for slit pot you could take a 30m and a load of shorter bits, but more risk of it getting caught up)

 

[Fjell]

I take three bits of rope down Simpson normally if there are two of us, 2x35m to pull down from above the slit and another rope to use before that. The second rope is initially used to rig the climb up and traverse. Split in two bags in case you toss one down a hole for some reason during a senior moment. If solo I take 2x35m.

If you are 100% certain about using Slit itself, then you can take 2x30m - but for me it has always been a struggle with full gear on, so I don’t risk it. Anyway, the pitch above is vastly superior - but it isn’t 2x30m.

You need very little rope to climb down the bolt ladder on the right of the last pitch.

 

[langcliffe]

Suggests that they were expecting to do two shorter abseils. People do both, depending on what they have available (for slit pot you could take a 30m and a load of shorter bits, but more risk of it getting caught up)

It actually suggests that they assumed that a single rope of twice the pitch length is the only way of rigging it.

 

[langcliffe]

Anyway, the pitch above is vastly superior - but it isn’t 2x30m.

You're probably right. I was more concerned with the technique than with the precise details of rigging a specific pitch.

 

[mikem]

It actually suggests that they assumed that a single rope of twice the pitch length is the only way of rigging it.

Yes, and when you have expectations, it can sometimes be more difficult to see the alternative solution

 

[Fjell]

There are several places in CNCC guides and topos where they mention using two ropes for a pull through. Do people not actually read Northern Caves as well to find the pitch lengths?

 

[Samouse1]

There are several places in CNCC guides and topos where they mention using two ropes for a pull through. Do people not actually read Northern Caves as well to find the pitch lengths?

I’ve taken the two ropes comment to mean that you carry a spare rope in case one gets caught?

 

[andrewmcleod]

I doubt many (newer) cavers have Northern Caves these days (except the new version). I certainly wouldn't dig it out to look at rigging info.

I could be wrong, but the CNCC guides I have seen have mostly talked about the requirement for a _spare_ rope, not splitting the rope in two.

If people are finding the description confusing, that might very well be entirely 'their' fault due to just not having thought about this properly - but equally a few extra words could probably clarify the situation.

 

[Babyhagrid]

I would be interested to know whether this is the normal approach, or whether people really do lug a 60 metre rope down Simpson Pot to descend from the top of the Slit.

I used a 50 and a 60 down Simpsons.
Means you can leapfrog the ropes a bit and rig pitches before the previous is derigged.

I also thought this was what we're supposed to do

 

[Fjell]

I’ve taken the two ropes comment to mean that you carry a spare rope in case one gets caught?

This is why you need to know the actual pitch lengths. And it is indeed a good idea to have a spare rope or two.

The biggest pitch in Swinsto is about 15m, but 30m in Simpsons. You might read people talking about how many 30m ropes to take, but they mean used in different ways. As I said, I would be slightly paranoid and not put your only exit in one tackle bag hung on a bit of string.

It is a serious issue if people don’t have access to the data in Northern Caves, because the CNCC descriptions are not complete enough and anyway don’t cover the majority of caves. One thing missing from topos is pitch lengths, which I personally think is an omission.

 

[mikem]

I would like to see pitch lengths included as it allows you to select ropes to fit together when you don't have the suggested one.

Although Northern caves also didn't give pitch lengths (some suggest 20m ladder, but only 25m rope!)

 

[langcliffe]

I used a 50 and a 60 down Simpsons.
Means you can leapfrog the ropes a bit and rig pitches before the previous is derigged.

I also thought this was what we're supposed to do

I find the words "supposed to" a little worrying in this context. It implies to me that you are caving by rote, rather than working out what is most appropriate given the group and the situation. However, at the end of the day, if one is comfortable carrying two long ropes down Simpson, that's fine

We use a couple of 30s for Simpson Pot. This allows one to leapfrog until the final pitch, where both ropes are used. That works for the Great Aven as well. In Swinsto and Turbary we use a couple of 20 metre ropes. If I was "leading" a trip, rather than my caving with my usual peer group, I would probably take a spare rope.

 

[mikem]

The descriptions are mostly written for people who haven't visited the site before. After that you can make up your own mind about what's required (although the topo only shows fixed rigging)

 

[langcliffe]

The descriptions are mostly written for people who haven't visited the site before. After that you can make up your own mind about what's required (although the topo only shows fixed rigging)

If that is a response to my post (and apologies if it isn't), none of the CNCC Route Guide, Rigging Topo or Northern Caves give the rope length requirements for pulling through Simpson Pot.

 

[mikem]

Interestingly Northern caves doesn't even mention doing it as a pull through, whilst swinsto does.

 

[Ian P]

If that is a response to my post (and apologies if it isn't), none of the CNCC Route Guide, Rigging Topo or Northern Caves give the rope length requirements for pulling through Simpson Pot.

Simpson Pot will be getting some “house keeping” work in the near future. I will make sure that accurate information for pull through rope lengths is published with the topo (as done for Swinsto).
For information. The largest pitches in Swinsto are the split pitches which are both exactly 14m each from the pull through anchors to the floor.

For Swinsto I have a 14m piece of 8mm rope with a 14 m piece of 5mm cord tied to it. This along with a 30m length of Petzl Rad line carried in a separate bag gives a very compact set up with a modicum of redundancy.

(I only use this system when solo or with peers).

 

[Steve Clark]

As for what people are 'supposed' to do - I did the CNCC pull-through course last year (or maybe the year before?). The instructors demoed both options - single rope with a fig 9 blocking knot in the middle, or two shorter ropes and a discussion over various ways to tie them together. And they made the point that you can tie together multiple shorter ropes on the pull-down side if you end up short for whatever reason.

Using that, you could do Simpsons on 35m + a couple of 20's I guess. If you lost one of the 20's you could still leave the slit pot hard rigged and have another 20m to get down the final and out.

We took 40+40+20+20 for a team of 4

I know your feelings on the extra carabiner business - that was specifically taught for larger things like scaffold poles / big rings, but people were using it more generally. I've stopped using it for normal bolts.

 

[langcliffe]

As for what people are 'supposed' to do - I did the CNCC pull-through course last year (or maybe the year before?). The instructors demoed both options - single rope with a fig 9 blocking knot in the middle, or two shorter ropes and a discussion over various ways to tie them together. And they made the point that you can tie together multiple shorter ropes on the pull-down side if you end up short for whatever reason.

Using that, you could do Simpsons on 35m + a couple of 20's I guess. If you lost one of the 20's you could still leave the slit pot hard rigged and have another 20m to get down the final and out.

We took 40+40+20+20 for a team of 4

I know your feelings on the extra carabiner business - that was specifically taught for larger things like scaffold poles / big rings, but people were using it more generally. I've stopped using it for normal bolts.

Thank you for that - I'm delighted to hear that using two ropes for a long pitch is being thought of as a normal technique.

I met a large party of students doing a pull-through in Simpson Pot last year, with three of them struggling with heavy rope bags.

I do not want to imply that there is a right way, or a wrong way. I just think that people could be asking themselves why they are taking a certain approach, and whether there is a more efficient away to achieve the same objective.

 

[mikem]

Using two ropes means that you just tuck one end through and tie them together, rather than hauling half a rope through the anchors