Crate Stacking and rope

[Ben Low]

Until recently I'd been of the view that it was preferable to use a dynamic rope with a crate stacking activity - the rationale being that the dynamic rope would be more suitable to absorb the energy of a fall, and would result in a lower maximum force on the climber. Those are both true, however are at odds with the risk of hitting the ground in the first few metres of the climb - even when properly belayed, due to rope elongation.

Prompted by recent discussion with Mark W., I did a bit more research and found that EN 1891 (Euro standard for static ropes) actually specifies a safe impact force limit (600daN or 6kN) for a fall factor 0.3 on a static rope. i.e. you can have quite a large (for crate stacking, essentially top roping with a nominal fall factor of 0) fall factor and still be comfortably within safe limits.

So I'm totally recanting any earlier statement that it's more sensible to use a dynamic rope for crate stacking - a wholly static rope is suitable in terms of limiting impact force when properly belayed, and is preferable to a higher-stretch rope so as to minimise the risk of hitting the ground in the first few metres.

FYI attached is the crate stacking risk assessment I did for last year's Jamborette (it was updated after the event, and I just updated it again re. rope type).

Yours in Scouting,

Ben Low

Venturer Leader
1st Balgownie Scout Group
0407 17 25 21
ben...@balgowniescouts.org.au

[Steven Pavey]

A very good point that you bring up Ben.

 

It can also be noted that any activity that has a top rope belay setup (e.g. rock climbing) should also be utilising static or semi static (a cross between static and dynamic) ropes. This is due (as you mention) to the reduced ability to have a fall factor that requires the need for the extra rope stretch owing to the fact that the belayer should have most of the slack rope taken out of the system, meaning that there should be no discernable drop in height

 

I will mention here that in my commercial outdoor work that all top roped activities that I have run (including crate stacking and top rope rock climbing) utilise static/semi static rope for the belay system and not dynamic (for reasons noted above).

 

Further more dynamic rope should be used in rock activities where there is a greater risk of a major fall that requires the extra rope stretch e.g. lead and sport climbing.

 

To further reduce the risk whilst crate stacking, it is possible that full body harnesses with a dorsal (back) attachment could be used instead of a sit harness with the attachment at the front. this can further reduce the amount that the participant can fall and also removes the risk of getting tangled up in the belay rope and in the event of a fall.

 

Yours in Activities

 

Steven Pavey

Shoalhaven District Activities Leader

Shoalhaven Rover Crew
---------------------------------------
There are no shortcuts to any place worth going.
If your not living on the edge, then you are taking up to much space!

--
You received this message because you are subscribed to the Google Groups "Scouts South Coast and Tablelands - Adventurous Activities" group.
To unsubscribe from this group and stop receiving emails from it, send an email to scouts-sct-advent...@googlegroups.com.
To post to this group, send an email to scouts-sct-...@googlegroups.com.
To view this discussion on the web, visit https://groups.google.com/d/msgid/scouts-sct-adventurous/CA%2B3mEukXfBKfvDy1ErzcVum5qtW_xY_k3RepNJxjS3cw0_JvvQ%40mail.gmail.com.
For more options, visit https://groups.google.com/groups/opt_out.