Tying blocks| pulleys| portawrap to trees| no slack| rope SWL| matching rigging

Ekka · 27th October 2007, 10:59 PM

How to tie those devices with little slack and make sure your rigging system is safe and matched.

So often climbers leave great amounts of slack in the attachment rope of pulleys and blocks, especially bad when knocking the head out.

This video demo's the following techniques including some slings I use.

Timber hitch
Cow hitch
Prussik
Girth hitch

By far, the cow hitch is the best way to attach your blocks and pulleys to the tree. The difference between a block and a pulley is a pulley requires another piece of hardware to attach it to the tree. A block has provision for it and blocks are designed to take dynamic loads.

Pay attention to Safe Working Loads (SWL) which should be stated on both blocks, pulleys and clevis shackles. Carabiners state their breaking strain and here in Australia the SWL of hardware is 20% of it's breaking strain.

The SWL for rope here in Australia is 1:6 or 16.66% of breaking strain. In the USA for rope its 10%.

In this demo my lowering rope is 6000kg breaking so in Australia it's 1000kg SWL and in USA it's 600kg.

It's important to match your gear, remember that the block or pulley experiences DOUBLE the force to that of the lowering rope. If you lower a 100kg branch the force on the lowering rope is 100kg but the force on the block or pulley is double that and 200kg.

I simply use double rope for attaching the blocks and pulleys, easily overcomes this issue.

This entire system of mine is matched then, think about it.

1000kg SWL lowering rope
2000kg SWL block
2000kg SWL sling attaching the block (doubled lowering rope)
1440kg SWL carabiner to attach to sections

Anyway, the video is 11.32mins long and 58.21mb WMV and the quality does improve after the first few minutes (it was produced on older software).

http://www.palmtreeservices.com.au/v...yingblocks.wmv

DBS · 29th October 2007, 05:57 AM

Thanks yet another for my collection...

27th October 2007, 10:59 PM	#1 (permalink)
Ekka Eric Frei Administrator - Brisbane L5 (Dip) Hort Cert III Arb + some Join Date: Jan 2007 Location: Brisbane Posts: 6,933	Tying blocks\| pulleys\| portawrap to trees\| no slack\| rope SWL\| matching rigging How to tie those devices with little slack and make sure your rigging system is safe and matched. So often climbers leave great amounts of slack in the attachment rope of pulleys and blocks, especially bad when knocking the head out. This video demo's the following techniques including some slings I use. Timber hitch Cow hitch Prussik Girth hitch By far, the cow hitch is the best way to attach your blocks and pulleys to the tree. The difference between a block and a pulley is a pulley requires another piece of hardware to attach it to the tree. A block has provision for it and blocks are designed to take dynamic loads. Pay attention to Safe Working Loads (SWL) which should be stated on both blocks, pulleys and clevis shackles. Carabiners state their breaking strain and here in Australia the SWL of hardware is 20% of it's breaking strain. The SWL for rope here in Australia is 1:6 or 16.66% of breaking strain. In the USA for rope its 10%. In this demo my lowering rope is 6000kg breaking so in Australia it's 1000kg SWL and in USA it's 600kg. It's important to match your gear, remember that the block or pulley experiences DOUBLE the force to that of the lowering rope. If you lower a 100kg branch the force on the lowering rope is 100kg but the force on the block or pulley is double that and 200kg. I simply use double rope for attaching the blocks and pulleys, easily overcomes this issue. This entire system of mine is matched then, think about it. 1000kg SWL lowering rope 2000kg SWL block 2000kg SWL sling attaching the block (doubled lowering rope) 1440kg SWL carabiner to attach to sections Anyway, the video is 11.32mins long and 58.21mb WMV and the quality does improve after the first few minutes (it was produced on older software). http://www.palmtreeservices.com.au/v...yingblocks.wmv __________________ Remember to use the "search" function, if you have answers/questions post them so everyone can benefit. Free Tree and Green Industry Link Directory Qualified Brisbane Tree Lopping \| Stump Grinding and Stump Removal Brisbane Brisbane Tree Care, Consultations, Developer, Tree and Arborist Reports Forum Sponsors

29th October 2007, 05:57 AM	#2 (permalink)
DBS Semi-mature vigorous tree Join Date: Jul 2007 Location: CT USA Posts: 205	Re: Tying blocks\| pulleys\| portawrap to trees\| no slack\| rope SWL\| matching rigging Thanks yet another for my collection... __________________ Stihl MS 200T Stihl MS 361

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