rope - advice please

[Bob Mehew]

chargen-Nr (I presume this is German for serial no or similar) of S 2014 0145 003 DR.  I suspect it is pretty new.  Also, I think Safety Super II has not been around for that long, it's the replacement for the superstatic.

The 2014 part is almost certainly the date.

 

[SamT]

As someone who was once a climber (and did many an abseil into sea cliffs) and then turned to caving - I cant recommend enough - the use of a rope bag/bucket.

Feed your rope one end in first (MAKE SURE YOU PUT A KNOT IN THE END!!!!) and feed it all in.

Dangle it off a sling below you as you abseil. No tangles. No tossing ropes over the edge only to find they blow horizontally across the crag and get snagged. No finding the end has got tangled in boulders underwater at the bottom of the see (seen that happen a few times on lundy).

Like this guy..

http://www.dolomitetraining.co.uk/sites/default/files/gallery-images/282/282-p8010023.jpg

Also - neat trick for stuffing the rope in...

How to load a new rope into a rope bag/Tying a bowline Knot

(I tend to put the krab on my chinstrap of a helmet when stuffing a rope bag).

Its less tiring than coiling. but perhaps a bit more faffy to carry on the long walk in. A large coil allows you to drape a 100m ab rope between the back of you neck and rucksack.

Spare rope can be stored in the bag at the base of the pitch and so tied on so it can be hauled back up.

What many cavers might not appreciate is that rigging 're-belays' on sea cliffs is not as straight forward as it might be in a cave with 3 appropriately placed bolt hangers in exactly the right place. Rope protectors are the way forward.  Also, you need to be able to haul the rope back up from above, which you cant do if its been re-tied half way down. 

I always found that a wild country ropeman worked really well as a prussic device. Better than.  I always used my belay plate to ab with a small prussic loop attached to the leg loop of a harness.  That way you can lock off if you need to/get struck on the head by falling rock etc.  Petzl simple is probably overkill, its just an extra bit of kit you need to cart about.

Looks like a great cliff/route.

 

[Fulk]

Bob Mehew:

Expected shrinkage is around 10% but some people claim it does continue with further wet dry cycles.  (I have not tired to quantify it.)

Here's one example, Bob:

Here?s one example ? Marlow 10.5 mm / 50 m. Won as prize at BCRA conference 20?09?98; measured on 21?09?98 as 25.79 x 2 = 51.58 m.
Soaked in bath on 21/9/98; measured on 23/9 as 24.46 x 2 = 48.92m. Shrinkage = 2.66 m, or 5.16%; 
measured again on 1/10/98 after use on a Swinsto Hole through-trip as 23.76 x 2 = 47.52 m, therefore shrinkage = 4.06 m or 7.87%.
Not measured again until 16/4/13, when it was 43.58 m, so shrinkage = 8.00 m, or 15.51%.

(probably time it was retired from use  )

 

[barrabus]

kp64zl: If you want to borrow a suitable rope bag (to go with the rope protectors - as already discussed) I can lend you one...

 

[Bob Mehew]

Thanks for info Fulk but I note your first wash was without agitation.  I am a bit skeptical that simple soaking will effectively remove the oils given the weave, pore size etc.  But this and other data implies that initial shrinkage may also be dependent upon the degree of agitation.  Hum, I wonder if I could get a grant for 100m of rope and a washing machine to test the difference between repeated wash v soak and then dry cycles.  Problem is it would have to be done on each manufacturers' rope.

 

[kp64zl]

Hi Barrabus

the rope bag looks like a very sensible solution for the reasons you state (no trying to untangle ropes half way down a cliff)

but doesn't it mean that there is no/very little weight on the rope, & therefore a very fast descent??

 

[barrabus]

...but doesn't it mean that there is no/very little weight on the rope, & therefore a very fast descent??

It means you get (almost) the same weight all the way down rather than loads at the top and virtually none at the bottom and you don't have to increase the friction as you go further down. Definitely worth practicing somewhere friendly before you do it on a big scary sea cliff though.

 

[barrabus]

...for the reasons you state (no trying to untangle ropes half way down a cliff)...

It was SamT who suggested it.

If you do decide to do this (or when practicing) you should also follow his other advice:

MAKE SURE YOU PUT A KNOT IN THE END!!!!

 

[martinm]

I wonder if I could get a grant for 100m of rope and a washing machine to test the difference between repeated wash v soak and then dry cycles.  Problem is it would have to be done on each manufacturers' rope.

You could perhaps apply for a research grant from BCRA for this Bob? It's important research. Regards, Mel.

 

[Fulk]

Bob Mehew:

Thanks for info Fulk but I note your first wash was without agitation.  I am a bit skeptical that simple soaking will effectively remove the oils given the weave, pore size etc.  But this and other data implies that initial shrinkage may also be dependent upon the degree of agitation.

My guess (and it is purely a guess) is that simple soaking will not remove the oil, but I doubt whether agitating the rope on its first soaking would affect its shrinkage.

 

[Bob Mehew]

Bob Mehew:

Thanks for info Fulk but I note your first wash was without agitation.  I am a bit skeptical that simple soaking will effectively remove the oils given the weave, pore size etc.  But this and other data implies that initial shrinkage may also be dependent upon the degree of agitation.

My guess (and it is purely a guess) is that simple soaking will not remove the oil, but I doubt whether agitating the rope on its first soaking would affect its shrinkage.

Slightly off topic but I suggested lack of agitation might imply less shrinkage since my works suggests nearer to 10% shrinkage for first wash using agitation by a washing machine.  My presumption is that the rope bending causes fiber movement through stretch and contraction.  I suppose one could check this by using pulleys of different size to pull a rope through as the agitation mechanism.  10% seems the sensible rule of thumb for first wash shrinkage and I will accept 15% overall. 

Unfortunately I am stretched on various other lines of research so this area will have to wait.  But perhaps a few clubs might be persuaded to do some measurements of their rope before and in use to flesh out the information base.  I am also worried about differences between manufacturers since when you look at the detail of the core you often find differences of detail.

 

[Maj]

Something else to bear in mind re rope shrinkage.
A couple of years ago I purchased 2 x 200m drums of rope, to be cut into various lengths for various club members. Just the action of removing the rope from the drums and being left untouched for a couple of weeks caused an appreciable amount of shrinkage.
I feel the reason for this is that when the rope is manufactured and wound onto a drum, it is wound on tightly under tension. Therefore when the rope is removed from the drum, it relaxes and loses some of its length (between 2 - 5%).

I initially expected the drums to contain a few extra metres, so I measured the complete drum and found it to be 200m. I divided the rope up into the various required lengths. After a couple weeks a couple of the lengths were remeasured and found to have shrunk, without having soaked or used the rope in any way.

Maj.

 

[potholer]

Well, if some of the shrinkage is down to the nylon irreversibly absorbing water, might that happen from the atmosphere even in the absence of washing?

Given that rope only seems to stretch ~3-4% under bodyweight, there would have to be a lot of tension on a drum to have it shrink 2-5% after removal.
I've never got the feeling rope on drums was under meaningful tension, let alone that kind of tension.

Also, if you took it off the drum, measured it and then measured it again later, even if it had been under some tension on the drum, wouldn't that be likely to have been elastic stretching which largely recovered as soon as you took it off the drum before first measuring it?

 

[Bob Mehew]

Well, if some of the shrinkage is down to the nylon irreversibly absorbing water, might that happen from the atmosphere even in the absence of washing?

Given that rope only seems to stretch ~3-4% under bodyweight, there would have to be a lot of tension on a drum to have it shrink 2-5% after removal.
I've never got the feeling rope on drums was under meaningful tension, let alone that kind of tension.

Also, if you took it off the drum, measured it and then measured it again later, even if it had been under some tension on the drum, wouldn't that be likely to have been elastic stretching which largely recovered as soon as you took it off the drum before first measuring it?

Forgive me for going well off thread.  Shrinkage and stretch is awfully complicated and fairly difficult to measure accurately.  However, I understand the rope manufacturing process has it under tension and one presumes under tension as it is wound onto a reel.  Rope is not a true elastic material; I am confident that there is a degree of permanent set (creep) when placed even under small loads and certainly the recovery time for a stretched length is far from instantaneous.  I don't think it is simply a question of water absorption by nylon; I fear the topic is fairly complicated and I have never seen anything which tells a coherent story on what is going on. 

 

[potholer]

I seem to remember that decades ago, one of the explanations for initial shrinkage doing the rounds was that there was some one-off water absorption happening on first soaking being a factor.

Though I guess that unless reeled rope was kept well wrapped, that would also happen on the reel, and it would tend to shrink in place there.

I guess rope (like Corde Courant) which comes packed loose in a box rather than on a reel would eliminate any reel/tension effects if it came to someone doing initiasl shrinkage measurements.

Since rope on reels doesn't seem to be attached to the reel very strongly (maybe a bit of sticky tape?) would it actually be possible to wind it on under muchtension?
At least until many turns were on the reel, it would seem hard to put bodyweight-scale force on it without it just slipping.

 

[Amy]

Rappelling with it in a sack can work for the first but everyone else still needs to be able to deal with the load.

When we deployed a 3000-ft long rope (approx 1000 meters, single piece!) at el cap we attached a 5 gal water jug filled with sand clipped to the bottom. This keeps the wind that is always there from grabbing it and if you are worried can also take care as to time of day. Mornings on cliffs can often be best as the cliff hasnt warmed up yet then to cause all the drafts. If the wind is enough to seing around a 50lb load on it while deploying it is probably a little sketchy to rappell it yourself...ive seen too many people get tossed around on only 700ft stuff when a wind whipped up. Trust me, being slammed into the rock while trying to rappel isnt fun.

 

[kp64zl]

Hi Amy, yes I saw that on your video. 

Looks like a cool idea - especially since you can empty it once you are down, making retrieval easier.