Ropes and Blocks

J

joe

New member
I ran across a couple of decent web sites this evening. 1 in particular brought a question to mind I'd like to get verified.

When rigging, it has been recommended
we use a safety factor of 10:1. However, according to this web site, if I read it correctly, one can get the same cycles to failure using a safety factor of 5:1 when employing a block. Anybody know about this and/or how this works, or why it is or isn't true?
http://www.treevolution.co.uk/documents/Tree%20Rigging%20Concepts.doc

This next web site has some food for thought on rope construction that will be appreciated here.
http://www.tensiontech.com/papers/ropecomp

Joe

p.s. Anybody care to share a web site pertaining to the subject matter?
 
I've noticed wear on ropes from using blocks that isn't typical. I have noticed the wear occurring near the working ends of my lines and I think it may be from the block cheek plates.
I've noticed when removing wood, the block will not rotate because it's attached to a sling that doesn't allow it to rotate freely. I think 1 solution to this type of wear would be to round the edges of the cheek plates of the blocks. This could stop the edges of the cheek plates from abrading the rope, at least slow the abrasions.

I can use swivels on rescue pullies to allow these pulley types to rotate with the rope. Any1 have a reasonable solution for heavy rigging blocks?

Joe
 
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, Tom , do you know what it says on this tag ?

- Joe , sometimes if you tie the Block too tight and don't leave a little neck than it won't rotate at all .
 
- Joe , sometimes if you tie the Block too tight and don't leave a little neck than it won't rotate at all .

Thanks, Glenn. I gather leaving a "neck" isn't the best solution either.

Does that clock hitch of yours help solve the rope abrasion dilemma?

Joe

[ January 27, 2002: Message edited by: joe ]
 
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