UKH

Hi all, 

I was doing some belay practice with my wife who's a fair bit lighter - practicing giving softer catches with her taking some bigger falls.

The first big fall of the session (factor 0.75ish) I was able to give a pretty soft catch but the catches after that weren't so climber friendly.

It might just have been me mistiming the jump, but I'm pretty sure I've heard that after a bigger fall the rope takes a bit of time to regain it's stretchiness. Is there a rule of thumb for how long that might be?

And if you take a lot of falls in a session, will the rope 'recover' between sessions? Does rope diameter affect the ability to recover?

And will a newer rope be able to regain it's stretchiness more quickly than an old rope that's taken a lot of falls?

Any opinions either technical or anecdotal welcome. Also any other tips for not breaking my wife's ankles...

Thanks

Ed

I'm sure people use a lot of different techniques for giving a soft catch, but I do find that trying to jump is really easy to mis-time and actually give a harder catch. 

Here's what I'd recommend: stand back while belaying and just allow the rope to pull you in towards the wall as you catch the fall. To see an example of this, just watch any ifsc lead event and notice how the belayers are doing it. 

You can get a bit of extra softness by adding a 'crouch'. As you catch the fall you can let the rope pull you to standing and walk in at the same time. The key with both of these techniques is to go with the rope, let it pull you, and control it. 

Are you calculating fall factor correctly? .75 is nearly decking out.

I'm pretty sure older ropes do lose some elasticity, yes. Although it's generally fuzzy sheaths, tangle proneness and general deteriorating handling that causes me to retire/replace them.

If taking several falls I usually swap ends and tie in on the other end to let the rope rest / recoil. 

A long time ago when Troll Eqpt still existed i went to a workshop by a tech rope person presenting. He said repeated falls without the rope having a rest is when the most potential damage is done falling on the rope when it has been stretched out and not recovered.

He said yes to rest the rope - lower off rest it in coils and then carry on after ten mins.

It was a guesstimate - 7th clip skipped, shoulders at 8th clip, falling to 2nd clip but with a dynamic belay

Thanks for this - will give it a go next time!

The fall factor assumes a non-dynamic belay. Any cushioning you provide will lower the effective fall factor impact on the rope, probably substantially if the dynamic belay you're giving is effective.

I very much doubt that a properly dynamic belay - as given in World Cup events - will stretch the rope to a noticeable degree, so it won't need time to recover. But if any fall results in quite an abrupt catch, I've read that it takes in the order of half an hour or so before the rope will regain its full elasticity.

Ok fair enough - probably not a particularly useful way of describing the fall in that case.

I'm surprised you don't think the rope would stretch on a big fall with a soft catch - even a toprope slump can result in quite a long bounce on stretch alone if you're near the bottom of a route?

It's not that the rope won't stretch; of course it will. It's just that I don't think any genuinely soft-catch fall will be enough to stretch the rope beyond its normal elasticity, such that it will need significant time to recover.

Ah right, gotcha - sounds reasonable. I wonder how many kN you'd have to generate for a rope not to immediately go back to it's normal stretchiness. Maybe I'm overthinking it and just need to get better at doing the work myself rather than relying on a stretchy rope...

These diagrams from.petzl might help. Fall factor is worked out before rope stretch/dynamic belay is taken into account. 

Falling from the 8th clip to the 2nd doesn't sound ideal though, that doesn't leave a lot of a margin for error if your partner falls lower down.

https://www.petzl.com/US/en/Sport/Forces-at-work-in-a-real-fall