Diff. Speedline. How to adj. tension by climber?

[southsoundtree]

I've been trying to figure out how to best terminate the speedline on the ground, and adjust it in the tree for lightweight conifer branches that can be dropped directly onto a slightly slacked speedline.


The normal way that I speedline light branches is by choking the trunk with a running bowline and have the groundie tension with a 2:1 or 3:1.

This seems to take too much time and communication.

I'd like to be able to slack the speedline in the tree to bump in up to the next whorl, send all the branches down, then have the groundie come into the drop zone, while I move the rope up, and sling all the next whorl.

I was thinking that a Whoopie sling would be one way to keep the rope close to the tree, and maybe use a munter-mule knot on a thicker steel biner, though the rope bend radius would still not be good, maybe 1:1.

I thought maybe a clove hitch around the tree, but haven't tried this yet. Maybe just two round turns on a bight and an half-hitch or double HH to tie off. I think that this would mean that the groundie would unclip all the branches before I'd be able to get enough tension off the line to slack, move up and tighten with the clove hitch, but I could at least slack the rope with the round turns and half-hitch, possibly making it easier on the groundies.

Seems like I end up spending too much idle time with the regular set-up. I'd rather the ground crew wait on me, than the other way around. Best yet, have one groundie, well timed with one climber. Two groundies depending on disposal methods.

Thoughts?

 

[Tom Dunlap]

Anchor/tie off the bottom

choke a sling on the top with a biner

Use a small diameter jigger/handybill/block n' tackle in 3:1 in piggy back mode.

Attach the jigger using a friction hitch

Tension the SL and snub it off with a mule or load releasing hitch.

Tie a stopper knot under the friction hitch in case the friction hitch slips. This will prevent the SL from going slack.

 

[southsoundtree]

Thanks Tom.

That's sounds like a great system.

I've never heard of the handybill or jigger, nor found them in a quick google lookup. What's the meaning/ origin of these? From context, I take it to be a MA system. I can picture a patch-eyed pirate, "Arrrr, git me a handybill."

 

[Tom Dunlap]

Yes...sea terms...I picked them up from reading Bryon Toss' books.

The simplest is a chunk of rope anchored on one end then rove through a pulley which is attached to the main line. Pulling on the other end will give a 2:1 which might be all that you need for tensioning a light SL.

The next step is to use a pulley with a becket and a second pulley. This will give you 3:1.

You aren't going to be able to put much of a load on the MA so you can get by with some small diameter cord.

The 4:1 MAs that are sold are WAY 'over-roped'. There's no need to use 5k# strength ropes in the MA since the load is divided by the total pull. Using 5k# ropes makes the rope portion into a 20k# system. The pulleys aren't even close to that strong.

A while ago I read an article from rope rescue where they were trying to figure out how many people were needed to pull a litter during a rescue. What they concluded was the rule of thumb that a person, pulling a horizontal rope, with good traction, can generate about 60% of their body weight in pulling power. So...[roughly speaking] a 200# person pulling on a horizontal 4:1 is only going to have about 800# of pull. Why use such large gear? I know...I would add in some safety factor of course...but, using 3/8" static line or even a high density cord would be sufficient.

 

[southsoundtree]

I tried this today. We were removing a big maple for a new septic system at a lakefront resort/ restaurant. The maple grew at the edge, so most of the branches were over the water.

We worked out some kinks, and it worked pretty decently. For this set-up, where the resort owners are doing the clean-up (two 20-something sons and a little kubota tractor) plus the two ground crew, it left them some dead time. My finnagling with the system didn't maximize efficiency, either.

I think that for a single climber, single groundie set-up, it might have its greatest application.

I tensioned by hand with a hitch minding pulley, and if I were to need it really tighten it up, I could use a Pantin, or a MA with a Pantin/ footloop.

I'll put some pics up once I get my new camera-USB cable in the mail.

Thanks, Tom, for suggesting what should have been a bit of an obvious method. I guess that I was stuck with my head in the proverbial box/ with the blinders on.

Its toughest, as usual, where the line angle is low. I think that low in the tree is where you need the most MA for line tension. A conventionally rigged (terminated at the tree with a choking knot, tensioned from the ground) speedline might be best for the lower part of the tree where line angle is bad and limbs are heavy. I think that transitioning to the climber-tensioned speedline part way up the tree, as limb size lessens, and line angle improves, might be a good way to use a complement of techniques for good success.


I don't know if anyone else uses this system and has any tips, or a good name for it.

 

[Roger_Barnett]

Re: Diff. Speedline. How to adj. tension by climbe

It's much better to do the tensioning on the ground end. In the tree, I'm occupied pre-setting numerous slings.....need to slack the speedline to get more than one attached. Then, make the cuts, and tension as needed. It helps to have HMWPE lines...they equal no sag!
for low line angle, use a pulley on the zip line...which needs a control line to get the assembly back to ya. Needs low stretch line and a tight set.