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limb selection


cerneARB
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yes but,if it fails you won't go as far!

 

Also,a redirect as discribed by Steve, will tend to compress the second anchor,rather than lever it over.

 

Good point. I was taught to always look to compress the limb down the grain as opposed to across the grain for Rigging.

 

If a limb comes out from the stem at 45 degrees or what ever angle have the main rigging pulley and re direct pulley/crane point so that the angle of the rope is the same going into the redirect/crane point as it is leaving the redirect/crane point. This means the limb would be compressed. In some circumstances the main pulley would be lower than the redirect/crane point. Vector forces.

 

I cant see why you could not use this for anchor points as long as the angles match.

 

Good point steve, Like the tip! :top:

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i had the job of sorting out a badly topped beech tree last year for roller. It had been topped at about 70ft, middle taken out and the sides pretty much left. i was able to have my ropeguide around a 10 inch stem just below the previous topping cut, then redirected right into the tips on a 3 inch stem. Beech is strong and i was happy with that small redirect anchor point.....though the risk of a short fall was well worth it for the ease it gave me to carry out the crown restoration. In that situation im also just a little bit more careful how much weight I put on my rope, and tend to remain lanyarded in even just for manourering through the crown. job would have been a pain in the ass without that anchor.

 

a well worthwhile trick to have up your sleeve

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Don't take this the wrong way Steve, I've watched your climbing and your a top climber no doubt.

 

I can't get the picture on this one. Correct me where I'm going wrong.

 

For example, you fix your anchor 50ft on the main stem, you then climb and put a redirect in 25ft above that.

 

In effect by putting that redirect in you are doubling the load on the redirect anchor point.

 

If you then come back down 25ft and the anchor fails you have 50ft of free fall line, you will hit the deck before the slack is taken up.

 

Would it not be better to put the main anchor up at the redirect site and half the load. It would still be in a compression state and just make sure you always have a second line if unsure.

 

Going back to basics, a climbing line from you round a pulley back to you only exerts half your weight on each side of the rope, 14st on the anchor point,

 

your two lines from your main stem anchor point over the redirect on a thin branch back to you exerts 14st on one side and 14st on the other, in effect you are putting 28st onto the redirect branch.

 

I'm just struggling to get my head round how this is better unless you are really careful and always have a second anchor point

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