UKC

NOT encouraging this in any way, but if one had to lead on a static rope how would one minimise the risk?

This is just to satisfy my own curiosity. Scenarios necessitating leading on static rope do seem unlikely.

Some leader falls were able to be held on hemp rope. In a thread some time ago there was a brief mention of Noyce's pre-war 180 foot fall in the Lakes when he was badly injured (but not by the rope): held by Menlove Edwards, hands severely burnt (also probably direct waist tie, waist belay with no locking twist round wrist, and no runners).  Jim Titt commented: "1/2" Hemp rope holds about 11kN so with a reasonably dynamic belay obviously worked fine". With current low stretch ropes ropes certified to hold several factor 1 falls, plus all the modern protection techniques and gear, holding a leader fall should be easier and less dangerous.

Routine measures taken with dynamic ropes to reduce impact on both rope and climbers would be equally applicable eg frequent runners especially early on pitch, wearing harness to spread load, gentle belay device. Grippy belay gloves probably invaluable to prevent burns and loss of control.

I don't know what the best belay method would be. Presumably not a Grigri or Munter, but possibly an ATC-XP/Mantis type device, and there would need to be the right balance between rope run to reduce impact and total loss of control. Probably partly dependent on the belayer...not everyone has the strength and tenacity of a Menlove Edwards.

Stupid suggestion? Tie several knots, eg barrel, in rope near leader. Each knot additively reducing force of a fall. Or use screamer between harness and tie in knot.

Interesting question, about what you should do if you had a gun to your head.  Could you deliberately choose a 'poor' belay device that slips if the force on it reaches a certain threshold?

Deliberately create rope drag, or does that make it worse under a dynamic soft catch belay?

Good point about the belayer giving a soft catch and using screamers - maybe you could make some similar energy absorbing stuff at a low force plasticity like quick drawers made of twisted carrier bags (backed up with a longer static link) or a succession of shoe lace loops you know will break (slack backed up), knots that will deliberately slide and tighten etc. 

Every cohesive material will stretch a bit, before it starts deforming plastically. Static rope's just far too stiff a material to be rated to not injure climbers of normal weight at its peak force under fall factor 2.

I've always thought that under the huge falls Dan Osman was taking deliberately jumping off, the impact force was less than fall factor 1 due to air resistance - is it possible to increase this, e.g. with a drag chute, or would that get in the way of the leader climbing?

Could the leader tie on as normal, but clip in further up the lead rope with a prussik, so the prussik will slide if they fall?  Or is that deliberately adding extra slack, which increases the fall length, I can't think how the fall factor equations work in this case, or if that's even an effective way of dumping the energy of the fall.

You could consider belaying using a Shunt? 

They are not a belay device, but could be used as one. The advantage is that they allow the rope to slip through when a load of around 2.5kn is applied. This would mean the system and lead climber should not get an excessive force in a fall.

Most static ropes in the UK are semi-static. They have falls and impact forces quoted. I’ve seen ‘not to be used in situations exceeding fall factor 1’ on manufacturers literature. Not ideal to lead on, but not totally ridiculous.

A small fall, high up with low drag on a semi static is probably preferable to a short FF2 fall leaving the belay on a dynamic rope.

Just use any device that slips rather than breaks - Prussik, Rescuecender, shunt or (the daddy) an ID.  They'll all slip before failing - although usually used more for rescue work than climbing.

Perhaps a pfpe device like an asap and asapsorber

I'd just stick to a dynamic rope.  

I know honnold used a 5.5mm static rope when he did his speed solo ascent of the nose. i think he only roped up for a couple of pitches, and did the king swing on it too. He told me that theoretically it could hold 1 fall...

f*ck that!

Sounds a possible solution. I suppose some falls would be dangerously long however.

I don't know how many people carry a shunt routinely (same goes for my suggestion of using a screamer).

I wonder if he had something dynamic in the system.

The idea of it is going to give me nightmares for a week. Your comment sounds appropriate.

Mind you a fall soloing would be certain death so even a slight chance would be worthwhile.

My thoughts too. Of course all leaders used to climb under these conditions without modern gear...hence "The leader must not fall" mantra.

Overall it would be of major importance to keep the fall factor as low as possible, even more than when using a dynamic rope.

I suppose the Dan Osman falls you mention were around factor 1 by definition as he jumped from near the anchor. I don't think air resistance would play a part in most climbing falls and unfortunately most of us wouldn't have a rapidly deployable chute if we were suddenly in a situation necessitating leading on static rope!

I wondered if it would be best if using an energy dumping system involving extra fall distance (eg prusik or screamer) to start leading clipped into a knot below this and unclip and bring it into play only after a fair length of (runnered) rope was out. But like you I really have no idea how all this would work out.

Minimise friction so whole rope streches and increase slippage at belay device - leather gloves so belayer can keep control.

If top bit of protection is high friction then falls become factor two on a static rope possibly breaking the top bit of gear or its placemernt.

Via ferrata devices employ a screamer in the system and they are designed to hold falls well over FF2 so that would seem a reasonable suggestion, though whether you would have one to hand when you "had" to climb on a static rope is the issue.

Slippage through a belay device, and dynamic absorption in knots, will both be pretty much insignificant compared to the assistance that can be given by an alert and mobile belayer. As long as you're on reasonably flat ground you can give 2m or so of dampened catch quite easily, whereas with plate slippage itself you're really looking at half a metre or so at the very most.

Cheers.  The last time I looked at fall factor equations (ignoring ground fall potential, which is seldom good, assuming we're on pitch 100 with an infinite clean fall out zone), you can just play around with extra lengths without changing the peak forces, as they're just deduced from conservation of energy between the momentarily stationary points (where kinetic energy is zero by definition).  If the ff was less than 1 , so you wouldn't  fall otherwise past the belayer, paying out slack increases the fall factor, but not above  1, - e.g. from 1 metre above the gear at 5m above the belayer right by the gear (ff =2/(5+1)=1/3 ), adding 40m more slack brings the fall factor up to ff=(2+40)/(5+1+40) = 42/46, much closer to ff=1.  However when the leader would otherwise take a fall that would dump them below the belayer anyway, ff > 1, adding more slack brings the fall factor down, closer to 1.  Plus you benefit from air resistance - e.g. from 5m above the gear at 1m (ff=2*5/(5+1)=a scary ff) adding 40m of slack results in a ff=(2*5+40)/(5+1+40)=50/46=a less scary ff.

I've personally always conjectured damage mechanics ('hardcore' plasticity) as well as fibres sliding across each other within the rope's internal structure must be where most of the initial potential energy of the fall ends up, as it must ultimately become heat.  I've never found a good model of rope damage mechanics though, and maybe other energy sinks are significant enough to avoid it.

The other assumption in the Fall Factor conservation of Energy Model is that the rope is perfectly linearly elastic, which I personally think is totally unrealistic - for one thing, the system is then conservative, and the full governing dynamic equations would determine that the climber bounces up and down on a periodic orbit forever.  It would be a great way of getting back to your high point and getting your gear back if you could grab on again, but this doesn't happen in reality because the model is junk as anything other than an upper bound!

Thanks for your effort. I knew there there must be a simple explanation that I could understand. 

When I was working Dr Dolittle, I was pretty confident in the holding power of the hand-placed peg and just about ready for a lead attempt. But just to make sure, I clipped my harness directly into a knot in the semi-static line I'd been using to top-rope work it, a few metres below the crux. It's a good job I did too, since when I fell off the crux, the peg slid out effortlessly and I fell maybe 6m or so onto the semi-static backup, which held me without any noticeably hard catch. In hindsight I should really have just made a knot a little lower than the gear and lead-clipped into it.

I also have a much more severe static line that used to be military and has almost no stretch at all (I don't think you can buy these retail nowadays) and I'm not sure I'd be quite so happy being caught on that from a lead fall.

Sounds good basic advice. However I know many say its difficult in practice to vary rope slippage through a device (I've never actually tried to do it when arresting a fall myself) and the post following yours gives a possible better option with an experienced belayer.  Obviously one possibility would be to choose the device available with the most appropriate level of friction (of course there is often a slicker orientation on the same device)...problem being I'd have no idea what  "appropriate" was ( your 'slippage increase' would imply the slicker option).

Thanks. With the popularity of sport and indoor climbing its great that many are experienced in holding lead falls and often in giving soft catches before they become involved in trad.

Though its impractical on a non-serious level I like the idea of using lots of knots to additively soften falls intriguing ....if one knot provides insignificant absorption then use five or ten until its worthwhile. Turn a static rope into a dynamic one!

I was going hypothesize a situation to cover the "had" in the first post but didn't as it was so unlikely as to be risible. But here it is: two parties on sea cliff with one ab rope, first pair ab down, second pair takes ab rope to ab elsewhere, first pair finds their sac contains another ab rope and not a lead rope.

While typing this I thought of another highly unlikely scenario where one might "choose" to lead on a static rope. After long walk in with keen but less able climber we pitch camp ready for a couple of days long, easy routes. However we have mistakenly brought only ab rope. Climbs well within my capabilities. Do we give up on weekend or do I take a  degree of risk leading?

Fortunately I've never made this mistake....though once I forgot to pack any rope at all.

Don't fall on the first pitch. Thereafter climb with a very strong, very alert second wearing clothing made from natural fibres (eg Harris Tweed), NOT man made, leather gloves and using a full body belay whilst standing braced on a firm stance facing out and well tied back to a chock stone?

That type of setup for leading on a static rope is possibly the only one of all those mentioned that has actually been proved to work! 

Not sure its been mentioned yet, but a low friction karibiner like a revolver on key placements or at least karibiners with wide back bars.  A lot of force of  fall is actually absorbed by the friction at this point.

I´ve deliberately led on a static a few times when I needed to get to the top to set up a working rope for bolting. Brought up on ten-year old, salt encrusted 1/2" Viking ropes a nice modern 10mm static is a luxury item!

Just use an ATC XP in the low friction mode and give the belayer a nasty pair of working gloves, they will never get 2.5kN on the rope. The preferred Euro solution would be using a "fast 8" and leather gloves, I´ve watched many competition belayers give absolutely perfect controlled belays this way, it´s just a matter of experience and competence

Thanks for your succinct reply backed by experience. I don't actually know what a "fast 8" is, though I assume a fig 8 descendeur with the rope threaded in the standard way.

A fast 8 is when you put the bight of rope through the large eye as usual but instead of around the central spine just clip straight into the karabiner, twists the rope less and useful with too much friction like using two thick ropes to abseil.

Build energy absorption and load limiting into the whole system rather than relying on the rope. Baggy fig9 tie in on the climber. I wouldn't rely on letting the rope slip through the belay plate, it doesn't seem very controllable or reliable. I'd go for a multi-directional low-ish runner with a roller on it, pass the live rope through a significant zig-zag of a couple of clips on heavy rucksacks filled with junk between the first runner and the belayer. Make sure the belayer has lots of space and freedom to move in toward the cliff. The combination of the bags being pulled into line with the rope then lifted, the belayer being pulled in toward the face and the friction at the top runner will all act to extend the fall limiting the peak force and absorb/dissipate the energy. Belayer is likely to get roughed up by the floor, flying bags of rocks and the cliff though. There is a bit of stretch in new static rope but it's not safe to lead on.

Alternatively: Just don't!

jk

Don't worry, I probably won't!

A very different response to the last. I'm not an engineer but your suggestion, as I understand it, is to remove more of the force of the fall from the belayer/plate and put it into the system leading to and including the climber.

If I was confident in my ability personally I'd still go for the simpler method, which is what what people used to do even before better rope, runners, belay plates etc.

Of course they are not mutually exclusive. One could use gentle plate, gloves, bags of rock, roller krab, better knots.

Incidentally if one did accept that its was worth slightly increasing the energy absorbing power of the tie in knot (using a fig 9) then surely it would logically be even more valuable to put several barrel knots in the rope near the tie in.

I thought The Fast 8 was the one without the late Paul Walker .  https://en.wikipedia.org/wiki/The_Fate_of_the_Furious

The answer is the same however you achieve it, the time/distance taken to decelerate the climber has to be extended. Personally I've no confidence in my ability to do that manually (literal sense of the word) so I'd favour a mechanical solution (stretchy rope ideally). Others with skills and gloves could probably do better. You can achieve a lot simply by moving about on your feet with good timing as a belayer.

Jk

I gave that film 8/10. Several days later, my Facebook account was suspended. Coincidence?! 

That only works if the friction through the top runner and the rest of the system isn't too significant.  I wouldn't mind betting that with the best belayer in the world, an 11mm typical stiff static rope going through a bunch of narrow bar karibiners all the way up the route would lead to an unpleasently abrupt stopping in the event of any significant fall !

1.  Don't

2.  I think it goes like this (*if* you ignore friction and assume constant accelerations):

The damage comes from force.  Force (F) = mass (Kg) x acceleration (m/s^2).  So a 100Kg climber (lardy but easy on the numbers) decelerating at 10g will experience a force of 10kN.

Acceleration is change of velocity (m/s) over time (s).  Final velocity is zero.  v^2 = 2 x acceleration x distance.  So if the stopping distance is 1m, and we're decelerating at 10g, the starting velocity is sqrt(200) = ~14m/s when the rope starts to act.

Kinetic energy = 1/2 x m x v^2 = 1/2 x 100 x 200 = 10kJ.  This started out as potential energy = m x g x h, so a velocity of 14m/s comes from a starting height of 10m.

So if you fall 10m and the rope stretches 1m (and the rider at the top applies), then you'll experience a force of 10kN.

If the rope is 20% stretchy, then it's 5kN

If it's only 5% stretchy, then it's 20kN

All the fall factor does is allow more stretch distance for the same fall length = lower acceleration = lower force.

3.  In practical terms, there is friction and your body also provides some stopping distance - reducing the forces.  However, a material fall (a small slip will be absorbed by your body) will generate forces that will almost certainly smash your pelvis, and quite probably make the runner(s)/belay fail.

4.  For interest, it takes about 4kN to break a human femur, although this is in a cross-load design-to-break situation on bones without the muscle protection etc.  However, it does show that we don't necessarily enjoy huge margins when taking big lobs on fat ropes.

5.  So, don't.

Rope stretch allows acceleration over 

I agree which is why I finished with "Just don't!"

jk

don't fall off

Cavers do, when required, so maybe ask them.

And it occasionally kills them.

jk

I could be wrong, but am fairly sure it is part of the Caving Instructor Certificate.

It's a long time since I've been underground but I remember reading a couple of fatal accident reports about cavers leading aid on static rope stripping pitches of 8mm bolts and rivets. On solid bolts the rope is largely superfluous with VF type gear.

Jk

It would be interesting to know what belay method was used and what was thought to be the cause. You seem to imply it might be due to caving bolts set up for static loads unlike sport climbing bolts (which probably wouldn't have failed).  I know little about caving but they appear  to use a variety of ropes inc. very static in US, low stretch kernmantel mainly in Europe (what I assume we are calling static in this thread) and rope of intermediate elasticity between this and our climbing ropes.

There has been much discussion in this thread of the dangerously high forces that would result from a leader fall on static rope.

However are we possibly (healthily) overpessimistic regarding outcomes? Some leader falls used to be held on hemp rope and we now have far better techniques and equipment, including better anchors, and runners to decrease impact force. Harnesses presumably significantly decrease damage to the body.

 It would be very important that the belay was really dynamic...as waist belays were. As I imagine it a device such as an ATC XP slows then stops a fall via resistance due to friction, bending rope and hand pressure (latter varying greatly between individuals). Presumably when this resistance is exceeded in a fall the rope runs through which significantly decreases a high impact force until the forces balance again (unless control is completely lost). My own totally uneducated guess would be that many belayers could exert sufficient hand pressure to progressively slow falls on static. Obviously there are limits as there is a maximum  dead weight an individual could hold and long higher factor falls would be problematic. Again guessing the rope would run some distance and so a glove on the braking hand would be absolutely essential to maintain controlling pressure (and flesh).

I think that Jim Titt basically said this in a single sentence but without all the hypothesising. Apologies if I'm misinterpreting.

I agree with the "Don't do this" point! Personally  I gain a lot from these types of discussion. I always wore gloves when using waist belays as a second but I should probably still do so sometimes with a belay plate. I'd like to think that I wasn't risking internal injury due to a fat dynamic climbing rope...I don't know if it has actually happened. Incidentally I suppose the opposite holds true with instances of decking due to rope stretch eg with spaced runners using skinny double ropes, though the force on hitting the ground is reduced.

It was half a lifetime ago I read the reports but it was pretty much worst case scenario IRC, static rope, self belay, low rated gear, sizeable fall due to alternating hand drilled bolts and hooks/rivets lead to the whole pitch zippering. Who knows, google may still turn it up if you search for 'cave aid climb static rope death' or similar.

jk