Below is a link to a short 'rough-cut' vid of an different MA technique for pretensioning a 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



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

Way to go Jack! Brilliant! Absolutely brilliant. Great idea and execution. Uses existing equipment and simple to fabricate from readily available materials.
Wiley

That is quite ingenious!!

Do other items like this exist on the market (i am not knowledgeable on commercial products)? I've always attached a simple 'rope' MA system to a standing rope whenever I've needed to tension/pull heavy items but it takes quite a few knots to setup (I am a knot head, so I don't really mind). Would love to see some pictures of others setups to do a comparison and learn something new as I'm probably doing it the hard was as well... (another thread possibly?).

Any plans on selling this commercially? Seems like it would be useful in many different applications (outside of tree work included).

I love it Jack! Very appropriately named too! Great work!

That's excellent! There may even be a climbing system or vertical haul system that can be evolved from that. One of the challenges is at the end of the pull where the ascenders start to go "off line", then the ascenders are fighting each other a little bit. Looks like with continued tweaking that could be figured out, obviously not a big problem. Great rope zipline tensioner.
-AJ

Cool...First device like this that I have ever seen.....

Thx, Y'all

A general reply to some of the various comments received:

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

I'm lovin' a really great suggestion 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 and maybe to lift light loads 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.

very slick Jack
:applause:

Tried 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.