Rescue-8 as a lowering device … question

[Hoowasat]

I’ve never done it, but I am familiar with the task of using a Rescue-8 (or Figure-8) for lowering limbs. One simply rigs the Rescue-8 as one would for rappelling … pull a bight of rope through the large opening and loop it around the leg housing the smaller hole, then secure the 8 with a carabiner … except the carabiner and 8 would be secured to the tree’s trunk (or to another tree nearby) versus being attached to one’s saddle. I am also familiar with the amount of twist a Rescue-8 induces on the rope while rappelling.

I do not own a port-a-wrap, and I’m considering using my Rescue-8 for lowering some large limbs from an oak in my backyard (the 8 will be tended by a groundie). The limbs probably weigh 200 to 300 pounds. My question concerns increasing the amount of friction from the Rescue-8. When rigging the 8 for lowering, have any of you taken the bight of rope through the large opening a second time before looping it around the 8’s leg?

I played with that double-loop arrangement a bit with my weight leaning back away from an anchor point, and it did indeed provide additional friction. It required much less force to “slow my descent” holding the rope’s running end. OTOH, I imagine that arrangement would induce much more twist on the rope than the standard fare. Am I thinking about doing something I shouldn’t? Would too much twist severely weaken the rigging rope?

PS - I originally posted this in the "Climbing and Rigging" forum, but got no response. Maybe moving it here may generate some input. Thanks in advance! <Ken>

 

[ATH]

those wings on a rescue 8 are there for increased friction... When properly used you should be able to stop the rope through an 8 with very little force. I would only use the wqay it is designed to be used. I'd worry about how it behaves when twisting with the rope wrapped wrong. Final note: once you use it for rigging, don't ever use it for yourself again.

 

[TREENATE]

I have a porta wrap, but if I can just give a wrap around a tree trunk I usually just go that route. As far as I know the rescue 8 ears are to prevent the rope from locking into a girth hitch on the top of the 8. That's a pretty common rappelling accident. The ears also make it easy to do a soft lock and act similar to cleats on a boat that you can tie off to. They are really bad for ropes though because of the twisting action. Also there is a big difference between a steel 8 and an aluminum 8 as far as abrasion resistance and strength goes. If possible, using the friction from a crotch and a wrap around the base of the tree is a good way to go and you won't have to take your 8 out of circulation as a rigging only tool.

 

[Pelorus]

BMS Belay Spool arrived today, won't likely get an opportunity to use it for awhile.
Not sure if any Arboristsite sponsors currently offer this device.
Has a MBS of 15000 lbs.

 

[climb4fun]

treenate has the right idea. take a wrap around the tree, run the rope through a crotch and have a ground guy run the line. there are other ways to do it but that's the least technical and easiest to set up.

 

[Pelorus]

treenate has the right idea. take a wrap around the tree, run the rope through a crotch and have a ground guy run the line. there are other ways to do it but that's the least technical and easiest to set up.

.........and it can be miserable to both the tree (if it is not a removal job) and the lowering line, and the amount of friction applied can vary considerably; inconsistent.

 

[CalTreeEquip]

I used the rescue 8 before it was even offered to arborists. They're great, easy to use and strong as hell. 200 - 300 lbs no problem with a single rap.
If its not heavy enough for you buy a Portarap.

 

[sgreanbeans]

I use them from time to time, when needing more than 1 point and as long as you are staying within SWL ratings, you will be fine. The point of having the gadgets is to avoid natural crotch rigging and wraps around a tree. As Pelorus said, using the trunk and crotches is not to good for the tree or the rope, so avoid when ya can. The one thing about a 8 is the bend ratio, try to avoid just running it thru the big O in the middle, like a pulley when rigging. Real bad for a rope when it is run off a sharp bend with a load. If you plan on doing a lot of rigging, look into the porta wraps, big and small. I have both, I use the mini instead of the 8 most of the time.

 

[Hoowasat]

After I posted my question, I found the following short video illustrating exactly what I had envisioned ...

Final note: once you use it for rigging, don't ever use it for yourself again.

THAT is a very good point! If I were to use a Rescue 8 for rigging, I will need to get another one ... a steel one for rigging only. And I agree with TREENATE that the wings are there to prevent the rope from forming a girth hitch which would be very difficult to undo once it's loaded. Being that I could not add or remove wraps from a Rescue 8 (or the BMS belay device) once it's loaded, I believe my best option is a port-a-wrap. THANKS for the replies and helping me see this from different perspectives! <Ken>

 

[Pelorus]

I'd prefer the option of using a friction device up top, than an unproven character on the ground running a porty.
Some folks find the concept of "letting it run" quite difficult to execute. I've worked with some of them. The atmosphere gets testy, and a lingering homicidal bitterness results. Takes sometimes days to get over.

 

[Hoowasat]

I'd prefer the option of using a friction device up top, than an unproven character on the ground running a porty.

When I'm working alone to help a buddy or family member I've never done tree work with, then yes, I like to control the drop rate (among other things). I'm fortunate in that the groundie who will help me with my own trees is quite good at following instructions and has a good understanding of the effects of shock (our day jobs find us building large seagoing vessels, parts of which he designed). Besides, he handled the ropes well when I trimmed a few of his trees last summer.

 

[2treeornot2tree]

One thing to think about is a figure 8 will twist up your rope as it runs through

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[TREENATE]

I guess it depends on the tree how much damage rigging off the trunk and branches will do. When I'm rigging branches it's usually for a removal anyway, so I don't care about what it does to the tree. Heavy loads will melt and glaze a rope a little, but if it's really heavy I like to use a porta-wrap for the extra control.