Negative Rigging

excellent Vid, thanks. With your narrative and video skills you could be making the big bucks!
 
Thanks. Some really great shots there Reg. Why'd they cut that pig... was it pulling up the sidewalk?
 
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  • #28
It'd damaged the water pipes under the house. The roots need to be cut as a result but not with the tree still standing. Protected tree, but the municipality granted the permit due to the circumstances.
 
Wow, Kenny, you changed your site. Lots of stuff there, nice resource! I've recommended mytreelessons to many folks for it's nice line up of friction hitches.
 
From yesterday. Beautiful weather all week

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Nice exercise, Jedi..

I'm coming back your way 10-14 for the real HS Reunion... and, if you ask nicely, I might just offer you a ride on the Wraptor.....:D
 
We're spurring up and down poles like that all the time, just as easy as breathing mate. It only took about a minute, so hardly worth breaking out ascenders.

Yeah you made it look as smooth as can be... just slightly more effort than walking up stairs..

x2 on the camera angle and slow mo of the splattering bark bits.. B&W etc... really nice cinematic production..
 
It's not anything that someone would notice without seeing it in slo mo or without being a professor. The changes in the dynamics would be minimal but it is good knowledge to have when pushing the limits.
 
Wow, Kenny, you changed your site. Lots of stuff there, nice resource! I've recommended mytreelessons to many folks for it's nice line up of friction hitches.

First time seeing it, awesome stuff! :rockhard:
 
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  • #39
If you made a cut straight through a standing log, then tipped it over, it'd pivot on the two edges and falls away before down. When you make falling cuts in a log, it pivots on the hinge. In a sense the log collapses on itself, the face creates a shortcut. In a rigging situation the shortcut creates slack in the line as the log folds. With no hinge at all, the log pivoting on the two edges, the slack would be minimal. Watch the vid again and you can see the slack in the line each time. With a winch type bollard, you can draw that slack out by pulling on the line as the log tips. You can to an extent with a fixed (no rotating) bollard too, but not as effectively. You can also reduce the slack by setting the block as close to the undercut as possible, and offsetting the face cut from the block. Does any of it matter ? Depends on the weight of your logs v the WLL of your rigging. In the video we had lots of height to play with including all the line-stretch that it afforded us, so probably not a worry. But when you start getting lower down, the chunks get heavier and you're having to stop them more suddenly, it gets a bit more serious.

The video shows the sling/block set ridiculously low. I'm not sure why they did that.

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Always a pleasure watching your vids Reg. Keep them coming buddy! Everyone here appreciates them (and I don't think that the TH members mind me speaking for them on this).
 
The video shows the sling/block set ridiculously low. I'm not sure why they did that.

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As well, the sling was timber hitched, which, while not optimal, is acceptable if the sling isn't long enough to be tied with a cow hitch, was way too loose. The log appears to have been pine, which isn't overly heavy. Perhaps the line was old and had been subjected to numerous shock loads. That line, due to its nylon core, has more stretch than our normal sem-static double braid lines, and should have been able to easily handle that log...which I'd guess weighed a mere 600 lb, if in fact it was pine....

Here's a cool DWT technique, which uses one line, unlike your twin system double rigging

https://vimeo.com/151423410

Mistahbenn commented on the blog, but he is wrong..... the system does work at greatly reducing loading, especially at the lowering device....and block smashing isn't as bad as it appears, plus that can be mitigated by moving the block to the side a bit.
http://www.climbingarborist.com/blog.php
 
The rope was too small.

Snot rocket science...

There is a lot more to it than the size of the rope.. if 3/4" is too small for that little bit of wood, how big a rope do you need???
something is wrong here.. hard to believe that was 3/4" polyd... definitely broke at the knot.. which begs the question what kind of knot should you use for negatve rigging... here'sa hint "its KNOT a running bowline"
 
A running bowline preceded by a half hitch is all I've ever used. No problemo.
And the running bowline has never been very difficult to untie after significant loading.
The half hitch absorbs a lot of the yank.
 
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