Rigging rope

[woodyguy]

Thanks for trying but still don't see it like that. The pulley has a 200kg load on it. A 10mm dyneema whoopie sling has a breaking strain of about 7000kg. It will only stretch by a mm or so. A 16mm Tenx will be less strong but stretch by at least 4-5mm. The load absorption needs to be in the rigging rope not in the sling.

 

Dyneema slings are a problem if you climb above your tie in point on non-dynamic static rope. Not because they snap generally but because the forces put upon you by your harness will injure you if you take a high fall factor fall. When I rock climb on dynamic rope with a 7-8% stretch then dyneema slings to tie in are standard because they are light and immensely strong.

 

Braking a falling section of tree needs several cm of stretch. This can only be supplied by the 20m length of rope (for example) that you are lowering it on and not by the few mm's of any type of sling.

[MOG]

agreed but i think it makes alot more difference than you think. yes the rope and letting it run is key. Sometimes you cant and sometimes it locks up for what ever reason, experiance, human mistakes etc etc.

 

i would say the tenex would stretch alot more than you think when it gets to its near/breaking point. So my thinking would be nearly break or at breaking the stretch is 10%, which i think is could make a massive difference when you are getting near those's loads.

 

 

Tenex-TEC from Samson Rope is a high-strength, low-stretch hollow braid polyester rope. Excellent abrasion resistance

 

16mm tenex

 

Average breaking 8500kgs

Minimum Breaking 7700kgs

 

• Elastic Elongation...

At % break strength

10% 20% 30%

1.4% 2.3% 3%

 

at end of the day this was the question, what would you use?.... and then i explained my reasons. no worries if you dont think its right or dyneema will do the job. yes it does but....a old company i worked for in Oz used the same 10mm dyneema amsteel for pretty much most jobs, but when it got to the really big stuff we got the 16mm or 18mm tenex out and the deadeye slings. Cheers for a good discussion.

 

and lets be fair we rig alot bigger pieces than 100kgs ay...

Edited March 26, 2013 by MOG

[woodyguy]

Thanks for discussion. Clearly the 18mm Tenex would do the job very well. Interestingly 18mm Dyneema has a 16 ton breaking strain!

I guess I prefer the 10mm dyneema whoopie as I can tuck it in my climbing harness easily and not notice it, whilst 16mm rope is pretty cumbersome. Keep safe!