Adjustable False Crotch?

tree md · Apr 20, 2010

Who actually uses one on a regular basis?

This is my next project to work with. Be easy on me, I am an old school guy and to be honest, I have never climbed on one. I do climb with a friction saver when applicable and use a sling and biner for a redirect but I have never actually rigged a pulley to climb on.

After thinking about it, it makes too much sense not to use one. I'm sure the reduced friction will be great on prune jobs but my main thought is being able to set one from the ground without having to isolate a limb.

If you are using one and are familiar with them what kind of setup are you using. I would imagine I will need to buy a static line to anchor the pulley?

Anyway, would love to hear some suggestions and comments on what works for you.

pdqdl · Apr 20, 2010

I am a little bit confused. I thought an adjustable false crotch would be a whoopie sling or some similar device used to hang a pulley or other low-friction device from. You would need to be in the tree already to attach that.

Your post seems to indicate hanging a pulley or other low friction device from an SRT line anchored at the base of the tree? Since learning that little trick here at AS, I do that almost always. It's easy and fast. My DRT setup gets raised into the tree, ready for use.

Nothing fancy, I just attach a 1/2" screw link onto the spliced eye, and raise it into the tree, anchor the rope by wrapping around the trunk about 5 times then tying it off. In that fashion, the knot is only a security, and there is no way for the rope to come unfastened by accident. Furthermore, my guys could lower me out of the tree if they had to, and all the necessary friction for controlling the descent was built in before I started up.

I just use any old rope I have handy; usually a good 1/2 arborist rope of some sort. NOT my 7/16" Velocity, since it is the DRT rope I raise into the tree. Damn! That reminds me...I need to cut out a section and splice a new eye...

I bought a friction saver and tried doing the "isolate a branch" trick. I decided that it was way more work than it was worth, and found a better way. Each of the climbers that have worked for me since then have liked that little trick, too.

tree md · Apr 20, 2010

Yeah, that is what I am talking about. I read about it in the TCC a while back and it just showed a pulley connected to a biner on a bight of rope with a figure 8 knot, hung in a crotch and anchored at the ground. It referred to it as a adjustable false crotch so that is what I called it. I have personally never seen anyone climb on one but it looks slicker than owl ####.

What kind of line do you use for your anchor line?

Bermie · Apr 20, 2010

Not quite what you guys are talking about...pulling up the drt on a single line with a pulley but...

This week I started using a sling, with a biner on one side and a biner and pulley on the other, for a friction saver...OMG soooo nice and smooth. Eeeeaasy up and down and all around.
Luckily I could climb up and set it nice and high, no need to set it from the ground and not very tall trees, but lots of leaders. Much nicer than a ring and ring friction saver. :cheers:

tree md · Apr 20, 2010

I haven't ever used that one either Bermie but I have heard it described here before. I think that trick is in the TCC too. Sounds like a pretty slick trick. I have been using a regular Buckingham 2 ring friction saver on prunes forever. I usually just use a natural crotch on takedowns.

I might have to give that one a try Bermie. Just curious, what kind of pulley are you using. I have seen it before somewhere and it seems like I saw it put together using a micro pulley.

pdqdl · Apr 20, 2010

A very useful reminder while using this type of tie-in point rigging:
http://www.arboristsite.com/showthread.php?t=114950

It really pays to not cut your down-line!

By the way: you can raise any kind of low friction device you like. I use a simple screw link, even though I have a very nice CMI pulley well suited for that purpose in my bag of toys. I just like the super security of 1/2" of steel with no moving parts. Friction is pretty low compared to the old school natural crotch I am used to. I might try the pulley next week, thanks to Bermie's analysis above.

Bermie · Apr 20, 2010

tree md said:
I haven't ever used that one either Bermie but I have heard it described here before. I think that trick is in the TCC too. Sounds like a pretty slick trick. I have been using a regular Buckingham 2 ring friction saver on prunes forever. I usually just use a natural crotch on takedowns.

I might have to give that one a try Bermie. Just curious, what kind of pulley are you using. I have seen it before somewhere and it seems like I saw it put together using a micro pulley.

Yes, I have the Buckingham 2 ring too...I'd seen this version demo'd by some of the UK guys that came here after hurricane Fabian, just decided to try it last week. BIG difference in friction, I'm liking it a lot.
I'm using a cmi micro pulley...the whole works comes out from the ground just like a regular friction saver...

I actually started with just a sling and a biner choked for a false crotch on a reduction/topping renovation last week, then realized using just the biner was too tight a bend, then remembered the pulley/biner combo...then decided to use the biner/pulley/biner friction saver...did I say I like it?

pdqdl · Apr 20, 2010

Bermie: How are you rigging that cmi pulley and the 'biners?

Is the rope passing over the pulley and then through the 2nd 'biner?

I tried that in my office, and it seems that sometimes the rope might ride pretty hard on the carabiner, depending on whether you were going up or down the DRT rig.

Also: what CMI pulley are you using? My tiny little slack tender pulley will fall right through a medium sized carabiner. My other light pulley would work fine for that, but doesn't like 1/2" rope: http://www.cmi-gear.com/catalog/pulleys/pullspecs.asp?partnum=rp115

tree md · Apr 20, 2010

Yeah, I could see where that would ruin your day PDQL. Hadn't really considered the possibility of cutting my own line but had thought about the potential risk of someone doing it on the ground. I was also thinking it could get a bit dicey if you were to swing a chunk off into your anchor line. I'm going to have to play around with it and see if I like it or not.

Bermie, a sling and biner is what i have been using for handy redirects. I never spend too much time on one though and I'm glad. I too do not like the bend radius with just a solitary biner. I'm going to give your suggestion a try the next time I need to use a redirect or friction saver. I keep a micro pulley in my diddy bag and it just gathers dust most of the time.

pdqdl · Apr 20, 2010

There was a big long thread a while back about how to anchor an SRT line. Not really much different than what we are talking about.

Despite all the different and perfectly suitable knots and other methods of securing the anchor point, I decided that I liked wrapping the whole line around the tree a bunch of times.

1. It CANNOT come untied accidentally. After 5 wraps on the tree, it really doesn't matter what knot you tie it with. Even if a groundie got really mad or stupid, it would take him a while to walk around the tree enough times with the rope until I began to come down.
2. Even if the loose end on the ground were fed to the chipper, it wouldn't yank me.
3. It really makes the base of the tree a visually obvious place to not mess around with a chainsaw.
4. As stated earlier, it would give my guys plenty of friction to untie the knot and lower an injured climber with. D Mc suggested using a port-a-wrap at the base of the tree to tie it off to, but I only have one, so I use it for lowering wood.

pdqdl · Apr 20, 2010

Some folks in the SRT camp tie their line off up in the tree, thereby preventing the groundies from goofing up and dropping the climber.

When I started using this setup, I worried about the downline quite a bit. Once you get used to it, it is pretty easy to keep it out of the falling wood and not cut it while you are working. It IS an important thing to keep in your mind at every cut. I suppose the SRT boys are always dealing with that issue, too.

Try it, you'll like it. It's awfully nice to climb your DRT the easy way: installed high in the tree before you ever get in the tree at all. Right now I am working up to getting all the pieces for my rope-walker setup. I just need the little bungee cords and then I am in business...

tree md · Apr 20, 2010

pdqdl said:
Some folks in the SRT camp tie their line off up in the tree, thereby preventing the groundies from goofing up and dropping the climber.

When I started using this setup, I worried about the downline quite a bit. Once you get used to it, it is pretty easy to keep it out of the falling wood and not cut it while you are working. It IS an important thing to keep in your mind at every cut. I suppose the SRT boys are always dealing with that issue, too.

Try it, you'll like it. It's awfully nice to climb your DRT the easy way: installed high in the tree before you ever get in the tree at all. Right now I am working up to getting all the pieces for my rope-walker setup. I just need the little bungee cords and then I am in business...

Yeah, being able to anchor on the ground is a big part of why I want to do it. I plan on trying it soon.

pdqdl · Apr 20, 2010

Regarding cutting your down-line: Just stay double tied as much as possible. After all, you always have your lanyard, right?

I was never that religious about always being double tied in until recently. That down-line is a constant reminder to pay attention to having a backup system.

tree md · Apr 20, 2010

pdqdl said:
Regarding cutting your down-line: Just stay double tied as much as possible. After all, you always have your lanyard, right?

I was never that religious about always being double tied in until recently. That down-line is a constant reminder to pay attention to having a backup system.

If there is one thing I can credit the first guy I started out with it's drilling into my head two attachment points before firing up the saw. And that was before it was even in the books I believe.

So yeah, I am pretty religious about that. There are always exceptions to the rule but I always try to be double tied in unless there is a reason not to be.

Nailsbeats · Apr 20, 2010

For friction savers I have a double ring and a biner/micro pulley and havent noticed much difference in friction. The double ring offers the most security while the biner/pulley allows you to just unclip the biner to disconect from the climbing line which is useful when you get back to the friction saver and begin working the spar down.

Going Dbrt off of an Srt pulley is smooth as silk although you will be putting more heat on your friction hitch due to the lack of friction at the pulley. I call it a floating false crotch because you can have the groundy adjust the length of the Srt line if need be.

Tree Pig · Apr 21, 2010

pdqdl · Apr 21, 2010

Nice pic SOM. That's what I thought we were talking about.

I guess that would reduce friction to about 1/2 that of a single non-rolling device like my screw link.

Bermie · Apr 21, 2010

That's it essentially S.O.M....

Less friction than the ring and ring, but not so much that I notice my hitch getting tighter.
The biner without the pulley is bigger than the other one, allows a keyring biner clipped into the little loop at the end of my climb line to pass through, but then catch in the pulley, pulling the whole works out.

I also like the idea of pulling up the drt system from the ground...going to try that at the next opportunity...don't have too many really tall trees to work just now!

Fireaxman · Apr 21, 2010

pdqdl said:
I am a little bit confused. I thought an adjustable false crotch would be a whoopie sling or some similar device used to hang a pulley or other low-friction device from. ....

I've been calling the TCC Page 50 trick a Height Adjustable False Crotch to distinguish it from the Diameter Adjustable False Crotch (whoopie sling or some similar device). Highly recomend it. You can get your down line away from the trunk as far as you need by tieing it to a neighboring tree or other suitable anchor some distance from the tree you are working, but that does put it at a little more risk for getting in the way of any branches you are dropping. Stihl, I have hit it with some pretty big branches without really being jerked around very much. Typicly a branch that gets hung up in the down line just slides on down like it was on a zip line.

I tie my DdRT pulley in with a big fat bowline with a yosimety tie off. Helps to keep the DdRT firm in the TIP. But since I use a pretty big pulley (2.4" aluminum) I don't really think the rig could pull back through a crotch anyway, unless you got a very big top hung up on it.

But then, if I'm topping, I'm taking down, and if I'm taking down, I'm on spurs anyway.

D Mc · Apr 21, 2010

pdqdl said:
There was a big long thread a while back about how to anchor an SRT line. Not really much different than what we are talking about.....D Mc suggested using a port-a-wrap at the base of the tree to tie it off to, but I only have one, so I use it for lowering wood.

A little explanation is in order. On that thread, I was describing a method for having instant lowerability for a climber using SRT with toothed ascenders. In this mode a changeover is required before descent. This makes having a readily available lowering system appropriate.

What this thread is talking about is setting up a floating false crotch with a doubled rope system. So with this system, there is a built in self-rescue component already in place. So going through the extra effort of hanging the porta-wrap is not really warranted.

What you do, pdqdl, with multi-trunk wraps is a good option. As you said, your groundsman can lower you with that setup. Another option is to tie two loop knots, alpine butterflies or in-line 8s, about two to three feet apart on the tensioned portion of the line. This is the system I am showing here. It requires cutting of the rope.

The plus side is all you really need is two carabiners. If one of them is an HMS, you can use a Munter hitch. But just having the two knots tied in a line allows any rescue system to be attached but doesn't force you to be dragging around extra equipment each time you tie on to a tree.

Dave

Adjustable False Crotch?

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