Rope Jack

[Jack]

Below is a link to a short 'rough-cut' vid of an different MA technique for pretensioning a rigging rope. It can attach mid-line and can run virtually any length of rope. Certainly not a new idea but one I've been contemplating for some time and finally put a few spare components together today to test the concept ... seems to work well. The MA is approx. 5+:1 -- no pulleys, no extra rope, min. weight, min. friction, quick, easy on-off, might work well 'topside', too ... we'll see ...

Rope Jack



[SUP]Just messin' 'round on a Sunday afternoon ... Anyway, kinda like the name, though ... can't imagine why [/SUP]

 

[bonner1040]

Hey thats awesome! Very creative...

Just a thought, if the device itself terminated to a prussick loop that was attached to a small line with a biner on it, you could attach that that biner to the porty and then once you were done tensioning, lock the porty and slide the prussick down. that would free all the tension on the cams and make removal alot easier.

 

[CurSedVoyce]

Clever idea..

 

[MasterBlaster]

That looks like quite the useful tool!

 

[Jack]

Hey thats awesome! Very creative...

Just a thought, if the device itself terminated to a prussick loop that was attached to a small line with a biner on it, you could attach that that biner to the porty and then once you were done tensioning, lock the porty and slide the prussick down. that would free all the tension on the cams and make removal alot easier.

Cool ... I'm so doin' that!!! thx

 

[bonner1040]

Cool ... I'm so doin' that!!! thx

Glad t' help, let us know how it works.

 

[bonner1040]

You might be able to sell that as a hauling device to rock climbers... especially if you make the jammers removable, and the handle separate, multi purposeful and all it would be cool for big wall.

I wonder what the max lift is? is it comparable to the Masdaam puller i wonder?

 

[treesmith]

Would the teeth on the ascenders not damage the rope fibers if a big load were placed on them? Seems Paul told me that the cover sheared at around 700# on double braids when using a toothed ascender. I may be mistaken on that. I was just thinking cammed ascenders would be better for that purpose. Novel idea though.

 

[SouthSoundTree]

Scott's concern was mine, as well.

What is the damage potential of cammed ascenders? Do they make handled, cammed ascenders that are like the typical CMI/ Petzl.

I really like the idea. Its very outside the box.

 

[bonner1040]

I actually tore a rope using a come along and a petzl hand ascender, so its def possible, but i was trying to pull a tree over and couldnt find the Gibbs... i guess if you made the handle short enough on the TJ and limited it to only only one person cranking you could understand the effect of the max load and determine if it would damage certain ropes by testing it.

Or just file the teeth down and see if it still works.

 

[Burnham]

If you've ever tried to smooth off the teeth on an ascender ...expect a tough job. Voice of experience. A hand held grinder would be the only way to do it.

Ushba makes a handled ascender that grabs with a smooth rocking anvil. But it loses gain on the grab more than the Ultracender and like products.

Clever idea, Jack. I'm leery of the potential for rope damage, too...but the idea and excecution is brilliant.

 

[bonner1040]

at the very least the modular handle could still be marketable to big wall climbers and anybody using ropes to haul normal loads in a vertical situation. It also has potential in rescue applications eh?

 

[Reddog]

Clever idea, Jack. I'm leery of the potential for rope damage, too...but the idea and execution is brilliant.

Same here, to many vids showing the jackets getting ripped on rope using toothed cams to a high level of pull.
Still a sweet idea.

 

[treesmith]

With a little ingenuity, (if one had the time and desire), a similar apparatus might be built using cammed ascenders, but where the handles ascenders shine is being snapped on/off line almost instantly. All the cammed ascenders (that I know of) require the removal of a bolt or pin and reassembly around the rope.

 

[Burnham]

With a little ingenuity, (if one had the time and desire), a similar apparatus might be built using cammed ascenders, but where the handles ascenders shine is being snapped on/off line almost instantly. All the cammed ascenders (that I know of) require the removal of a bolt or pin and reassembly around the rope.

If you've ever tried to smooth off the teeth on an ascender ...expect a tough job. Voice of experience. A hand held grinder would be the only way to do it.

Ushba makes a handled ascender that grabs with a smooth rocking anvil. But it loses gain on the grab more than the Ultracender and like products.Clever idea, Jack. I'm leery of the potential for rope damage, too...but the idea and excecution is brilliant.

 

[PCTREE]

Jack, that is such cool idea. So cool I would almost be inclined to put a provisional patent on it...... would definitely need to figure out the rope damage issue but what a cool idea

 

[Jack]

Thx, Y'all

A general reply to some of the diverse comments:

Them's my Sunday-go-to-meetin' Crocs ... thankyouverymuch ...

I'm lovin' that much better idea of putting a prusik loop in between the CMI and the 'biner so the load can be released without backing out the cams ... great improvement, IMO!

Yeah, I'm thinking' the "Rope Jack" is just for light loads! It ain't gonna replace my Maasdam - fo sho. The 'hope' will be to use the "Rope Jack" to remove slack & stretch for lowering and maybe to lift the tips on light limbs without having to break out the big guns.

Cams, even 'untoothed' like a Rescucender and Gibbs, have been shown to shred a rope with high loading. There are much better tools for the heavy work.

The short handle gives a leverage of roughly 5:1 ... I figure the max. I can apply with one hand will be a safe limit for the ascender and to keep from shredding the rope.

One important note about that handle: The handle in the vid is a section of a good quality hickory axe handle ... worked OK. First attempt was with a 1X2 pine board ... it BROKE - I went a**-over-teacup ... sorry no vid of that.

 

[woodworkingboy]

Some pullers have an aluminum handle that is designed to bend before reaching the maximum safe pulling capacity of the device.

 

[Porkbrick]

cool idea.

 

[rskybiz]

Like the idea also The prussic another nice idea.

 

[Jack]

Hey thats awesome! Very creative...

Just a thought, if the device itself terminated to a prussick loop that was attached to a small line with a biner on it, you could attach that that biner to the porty and then once you were done tensioning, lock the porty and slide the prussick down. that would free all the tension on the cams and make removal alot easier.

A B42 tied in a loop and girthed to the CMI and run through the 'biner worked well - held all the load I was comfortable applying and released well. So there was no need to back the cams out like in the vid. A B53 held well but was too hard to release.
Great improvement - thx.

 

[bonner1040]

Looks great Jack!

 

[Jack]

Had the chance to use the Rope Jack up top for the first time.

There are many ways (& reasons) to lower a limb solo. The video below uses a Belay Spool, a Rope Jack and a 'French' Prusik.

<iframe width="640" height="480" src="http://www.youtube.com/embed/krDkb0CibSY" frameborder="0" allowfullscreen></iframe>

1st came the Belay Spool for consistent friction;
2nd the Prusik for controlled lowering;
3rd the Rope Jack for pretensioning;
4th, hopefully, will be a release. For now, an un-trained groundy is still required.

"All things come to those who wait." - Violet Fane (Tout vient qui sait attendre)

 

[SouthSoundTree]

For your release without a groundie, you can set-up a double whip tackle with the sling on the 'work' with a biner, having the rope run from the BS, through the 'biner and the rope terminated on the tree, when you lower the piece to the ground, you can untie the termination knot in the tree, pull your rope, leaving the 'work', sling and 'biner on the ground.

Does that explanation come through clear as mud?

 

[Jack]

Perfectly clear. I do like the DWT idea for release ... have considered it but does require twice the amount of line. It will probably end up as the most practical method. Thanks!