Prussik loops for zip lines and mechanical advantage systems

[felixthelogchopper]

I'm after a bit of advice regarding Prussik loops to use on 14mm and 18mm rigging ropes. I want to use them for tensioning zip lines and also for attaching pulleys in a mechanical advantage system. It's not for anything huge, just a way to avoid lugging a Tirfor into the woods. Am I right in assuming that 10mm cord would be up to the job and would I be best with longer or shorter loops(70 or 50cm)? Thanks for any helpful advice,

[Joe Newton]

I'm after a bit of advice regarding Prussik loops to use on 14mm and 18mm rigging ropes. I want to use them for tensioning zip lines and also for attaching pulleys in a mechanical advantage system. It's not for anything huge, just a way to avoid lugging a Tirfor into the woods. Am I right in assuming that 10mm cord would be up to the job and would I be best with longer or shorter loops(70 or 50cm)? Thanks for any helpful advice,

 

 

Hi Felix. I use discarded hitch cord from climbing for tensioning zip lines. Usually around 70cm eye to eye cords, just put as many wraps as you can on.

 

Can get a photo if it would help?

[felixthelogchopper]

Hi Felix. I use discarded hitch cord from climbing for tensioning zip lines. Usually around 70cm eye to eye cords, just put as many wraps as you can on.

 

Can get a photo if it would help?

 

Cheers, Joe. I'm ok with the 'how?', just needed advice on the 'with what?' aspect. I was looking at something like this.

 

TEUFELBERGER SIRIUS PRUSSIK LOOP - 10MM X 60CM & 70cm | eBay

[Joe Newton]

If you insist on buying new cord, that would work fine. A klemheist would be a good knot.

 

Seems a waste not to put all those old hitch cords that are retired but can't bring myself to throw away to good use though!

[Joe Newton]

On an 18mm rigging line I would think 8mm would be too thin though.

 

Why on earth a person would want to use 18mm line for zipping is beyond me though!

[felixthelogchopper]

If you insist on buying new cord, that would work fine. A klemheist would be a good knot.

 

Seems a waste not to put all those old hitch cords that are retired but can't bring myself to throw away to good use though!

 

I'm strictly a ground dweller so I don't have any used loops. I figured that I should just buy a couple of new, CE marked ones seeing as they weren't overly dear.

On an 18mm rigging line I would think 8mm would be too thin though.

 

Why on earth a person would want to use 18mm line for zipping is beyond me though!

 

It would be down to what was in my truck that day, Sometimes the bag with the 14mm is in there, sometimes it's the 18mm as I have the big Tirfor with me.

[BenR]

10mm works well for me on a variety of diameter host ropes. If you are using prussic to hold the tension on the line (rather than locking off to a bollard etc) I would go with tandem prussics one long and one short.

[Craig Johnson]

tape slings tide on with a klemheist is what I've always used

[felixthelogchopper]

10mm works well for me on a variety of diameter host ropes. If you are using prussic to hold the tension on the line (rather than locking off to a bollard etc) I would go with tandem prussics one long and one short.

 

Is that not a pain to adjust? I like the idea of being able to easily put some slack into the system to make it more convenient for the climber to attach the slings to the line. My thinking was that with a prussik it would be quicker to adjust than it being tied off somewhere.

[felixthelogchopper]

tape slings tide on with a klemheist is what I've always used

 

That could be a goer. What are they like to adjust?