Span rigging advice needed

Benjo75

Benjo75

Treehouser
Joined
Nov 8, 2016
Messages
918
Location
Malvern, Arkansas
Hey all. I've been watching what vids I can find on span rigging. Nothing that really explains it very much though. I sure could have used it yesterday if I had been more prepared. We showed up as the job and the only rigging point had blown out and was laying on the house. I'm glad it did since it surely would have broken out as soon as I started rigging off of it. A bunch of fence row Hackberries. Four about 14 inch dbh and 65 ft tall and one about 36 inch dbh and 80 ft tall. Everything was hanging over the neighbors yard which we couldn't use. If I had had a 300 ft rope and confident in span rigging I could have used 2 other trees and rigged them back on our side. I think.

I get the basic concept. Terminate one end to the tree you're in, go through a block on the other tree. Down to a grcs or other way to tension it. Tie the piece on, cut it and it slides to the middle and is let down between the two points. There is a lot I'm missing though. I'm assuming a block would work better than a steel biner for sliding. Then a strap or piece of rope with a cow hitch? A rigging ring over the rigging line for sliding?

Any good vids explaining this or links that would be helpful?

I ended up going 20 ft higher than my nearest rigging point and ziplining small peices back to the safebloc then a slightly bigger piece which would release everything into a freefall. Which caused everything to drop a little over 40 ft. Worked fine cause all I had to clear was the roof and a fence. The rigging point was a small hackberry that was tall and spindly. Couldn't take more than about 150 lbs at a time. Wasn't ideal but it worked. I think span rigging would have been better.
 
Another rope going through another pulley in the support tree can be used to pull the rigging point to where you want to let it down instead of having to lower it where the rigging point comes to rest.
Fascinating stuff to me, and I’ve only done it twice, but it sure opens up some options. Takes ALOT of rope and hardware.
If the weight isn’t too much and you’re not shockloading it, very often less expensive pulleys will serve just fine too. I love the Omniblocks. The Pinto and Pinto Rig pulleys are nice and strong too. And yes, in some cases just a carabiner or two carabiners for harder angles work well.
 
  • Thread Starter Thread Starter
  • #4
I've seen a couple of vids where they installed everything from the ground and retrieved it that way too. I spend quite a bit of time in the bucket so setup wouldn't be too big of a deal. Just a little extra time and equipment. I see the biggest advantage is having a rigging point where none exists.
 
Indeed. Easy to install with throw line. Set some foating blocks. High line can go through a crotch above and basal tie. Easier set up with a trolly, but you can even use CMI pulleys that are very reasonably priced if the loads are small. I shared that yarding system i did recently on here somewhere. Porty for the control/haul back. Winch on the main line pulling the load up to the pulley and lowering off its capstan when you reached mid point. just need friction at the haul back to raise the load to the pully on the high line to raise and keep the load as it is winched along the high line.
I know. i know..... clear as mud :/:
 
Second that, CMI pulleys might be the best value pulleys from a reputable company. Not fancy and don’t have the soft textile-friendly edges like a lot of DMMs, but the edges don’t need to touch ropes or slings anyways. Just reliable performance workhorses and very reasonably priced. Bomber blocks too.
 
That large SS pulley is a 20,000 lb rated CMI if i recall correctly. Will take a 5/8ths line and is under 100.00
Ive done this with the little CMI pulleys guys use for hitch tending that are rated around 5k for really light loads or zip lining heavy limbs that dont exceed that 10% load.
 
I’m thinking about a new 5:1 MA setup with the double sheave CMI micro pulleys. Thread a pair of those with 150’ or 200’ of some of 3/8” polyester double braid and stuff the whole kit in a separate bag. I really don’t care about the recommended bend radius on static pulls like that on polyester or nylon.

Honestly, because it’s made by CMI is a big reason I’m keeping my old gold RopeRunner until I can’t climb anymore.
 
I'm not going to pretend I'm even an armchair expert on this type of rigging, but i am a pretty good industrial rigger and we drift loads sideways all the time. I feel the need to comment, because from my training, span rigging is awesome for some stuff, but less ideal for others. The scenario you mentioned involved what to me sounds like you would have needed to drop loads onto the skyline, which because of the force multipliers involved is pretty much a no no. Even with speedline use, they recommend catching heavier pieces first, and then gently easing them onto the skyline, especially if you are controlling their decent speed.

Here's a rigging situation similar to what you had to do, and they used another tree as a rigging point to drift the limbs to a suitable landing area. They caught the limbs first, and then just eased off the rigging line while keeping the drift line taut, which will swing the limb to the landing area. This would be very easy to setup from the ground as well.





This one they didn't have a sturdy enough tree to use to drift, so they caught the piece, then lowered it down a speedline towards the base of another tree. You could do this even with a truck as an anchor if needed. I personally would feel better blocking/ rigging and controlling the forces than using a skyline under what I'm rigging out.


 
Its actually pretty easy to first catch the piece on a block, and then use that line to lower into the high line. Often times, just slack the high line, catch on block, then tension the high line. Granted you have already done the rigging into the pulley. But the piece can be held by porta wrap, through that block. By then pulling on the winch line after tensioning and keeping tension on the lowering line, the piece will suck back up to the high line as it is being pulled by the winch line. I know, again, clear as mud. :lol:
But yes, takes more planning when blocking down.
 
Another point about drift line set ups is less personnel needed. Rob and I have taken down 100 plus foot pines, just the two of us, with a proper friction devise worked by the climber a loft after the piece was caught by ground man. The he takes over on the drift as the climber holds the load/lowering line.
 
I've used them where the groundie simply ties the drift line off, and the points were close enough that was sufficient. You can also use the same tree, just a different limb too.
 
High line, movable rigging point, controlled lift/lower. It’s the HOLY GRAIL!
loggers been doing it forever. Unfortunately their ‘walking trolleys’ (I forget the name perhaps mr. Beranek can refresh my memory), weigh hundreds of pounds. Far too much weight for us arborists.
If someone could invent a Controlled remote release pulley that doesn’t use a toothed cam, I would be all over it

a hot air ballon is a contender, lol
 
The logs we did on this job, we had to keep off a slope above the house, a service line and a manzanita the HO wanted saved. Having me mind one rope while he did the other and the ability to swing the top or log some by hand while I minded the lowering rope was good for this one. Basically using the large porty like a block and the tag with a little tension higher up to take part of the force.The logs we did on this one, IMG_20120406_140117.jpg IMG_20120406_144225.jpg IMG_20120406_144328.jpg
 
frans said:
High line, movable rigging point, controlled lift/lower. It’s the HOLY GRAIL!
loggers been doing it forever. Unfortunately their ‘walking trolleys’ (I forget the name perhaps mr. Beranek can refresh my memory), weigh hundreds of pounds. Far too much weight for us arborists.
If someone could invent a Controlled remote release pulley that doesn’t use a toothed cam, I would be all over it

a hot air ballon is a contender, lol
Click to expand...
Carriage I believe Frans. Some are HUGE
 
The Keanu looks sweet and probably more affordable than the Offya. I’m not seeing it for sale anywhere. Not sure if I’d actually get it though if given the choice between that and a half dozen blocks and some heavy duty rigging plates that are proven to take whatever I can throw at it.
I’m just kind of a whore for fancy looking gadgets. :D
 
You must log in or register to reply here.

Similar threads

C
Rapid Fire Rigging Questions
Replies
10
Views
941
cashstore
C
friedrich
i broke my spar (with tip)
Replies
22
Views
1K
TINYHULK
TINYHULK
Dopey
Need some equipment advice for my pruning job.
Replies
11
Views
423
Bermy
Bermy
Eric H-L
Long but light branch equals big excitement for a newb
2
Replies
32
Views
1K
WoodCutr
WoodCutr
Knotorious
Prevention of Milking; Are There Consequences?
2
Replies
37
Views
1K
SeanKroll
SeanKroll
Back
Top