Climbing a mast using prussic knots

[bbg]

How does one do this? I assumed one would need two knots: one for a rope giving two loops for the feet, one for the harness. I assume it would also be prudent to have a third knot on a separate halyard for safety.

Is this correct? If so, how does one tie a prussic knot?

 

[philip_stevens]

This video http://www.instructables.com/id/Tying_a_Prussic_loop/ or this http://www.animatedknots.com/prusik/index.php will show you how to attach a prussic/prusik loop. Tying the ends together is another knot - http://www.animatedknots.com/double...ge=LogoGrog.jpg&Website=www.animatedknots.com

 

[Spyro]

Also known as Prusik Loops. I've done it before on my own with loops made of 14mm rope around the mast 2 for my feet one slightly shorter than the other so they are level when my feet are in them. Another loop above these from which I attached a bosuns chair to. Sit in the chair attached to the top loop. feet in the bottom ones, slide the feet loops up then stand in them and slide the chair loop up, then sit in the chair and slide the feet loops up and so on. Getting around fittings and spreaders can be quite tricky but when you get to the top it is very comfortable with you weight spread between the chair and the feet loops.
If you can get help from a strong person a bosuns chair attached to the main Halyard and another for safety is much easier.

 

[nathanlee]

How does one do this? I assumed one would need two knots: one for a rope giving two loops for the feet, one for the harness. I assume it would also be prudent to have a third knot on a separate halyard for safety.

Is this correct? If so, how does one tie a prussic knot?

I used to use 6mm chord for prussic loops, it's safe enough.

There are three prussic loops, but I always seem to end up using the klemheist (not sure if I got the spelling correct there).

You need one loop for a single foot, and one for the harness. It's dead easy, just takes some trust in knowing you've got it right.

The hard bit, is getting back down again. You'll need either a figure of 8 belay device, or a crab and use an italian hitch.

What you need to do is take the weight off your foot (dangle on the harness), sort out the belay which is also attached to the harness, using the dead end of the rope, then put your weight back on the foot prussic. This will hold you still while you untie the harness prussic, then when you're done, undo the foot prussic, and rap back down.

On another note... I don't understand why there's a need for safety lines. I mean, of course I do understand, but why is marine rope less capable than climbing rope? We never had backups when on rock faces, unless using a double or twin rope, but often it was just a single 12mm rope, and we took some BIG drops on those, trusting it with your life. Why is marine rope different?

 

[pagoda]

I've been up the top via the conventional winch/halyard route - and self-propelled.
Self propelled, using friction-knots works perfectly well, but is quite slow.
I use the Bachmann knot - using a carabiner and 6mm line. One longer loop to stand up in -and a shorter loop for the chair. The grip of 6mm line on the 12mm halyard is excellent, using 3 or 4 loops round the carabiner. It's quite easy to slip the line up, but less easy to come down. You DO NOT touch the carabiner under load, just when moving the loop as required. The spinnaker halyard is best for height on my mast.
have a google for it - or http://www.marinews.com/Bachmann-Knot-522.php

Graeme

 

[fergie_mac66]

I find it easiest with one loop for both feet(holds your feet close together on each side of the mast) and one for a climbing harness.

 

[pandos]

6mm, or even 4mm for loops, one on the harness and one coming down and spliting into 2 to form stirups. This way your feet will grip each side of the mast.

I use 2 lines both pulled to the top of the mast connected to both my topping lift and my main halyard.

Pull one taut and and ascend this. Fit your figure of eight ready for decending on the other. As you climb use the second as a safety by moving your figure of 8 upwards. And tying it off.

When you want to come down, Transfer your weight to the non taut line, take the prussic attached to your feet off, loosen the other and abseil down sliding the prussic attached to your harness with your left hand. And your right hand well in under your arse.

Even if you make a mess of it the prussic will catch you, and you will be able to self rescue, or if your knocked out somebody will be able to lower you down by releasing the halyards.

Easier with jumars, but great to be able to go up and down without needing help.

 

[misterg]

Klemheist for me, too - 2 loops: one short one to the harness, and one longer one for a foot (you don't need both feet). I used my (stretchy) climbing rope as a back-up / escape rope - Doubled it, and tied each half separately to the jib and spin. halyards and hoisted it up the mast. Climbed the main halyard after tying it off around the base of the mast.

As a back-up, I tied a karabiner into the climbing rope and clipped it to my harness - moving the knot up every few feet as I climbed. (Actually I tied into both halves of the rope, but that was almost certainly overkill). Beware of using a normal (static / non stretchy) rope like this, because the shock of being caught by it if you fall might well break your back. It's a lot easier to ascend the halyard than the stretchy climbing rope, though.

Come down by fitting a descender to the doubled rope while standing in the foot loop, transferring weight, then undoing the loops from the halyard. I think this is the most risky part.

I have tried Bachmann knots, but found that they had a habit of slowly slipping. It all depends on the relative diameters of the rope and loops, and how rough they are, so you need to experiment a bit to find something you're confident in.

On another note... I don't understand why there's a need for safety lines. I mean, of course I do understand, but why is marine rope less capable than climbing rope? We never had backups when on rock faces, unless using a double or twin rope, but often it was just a single 12mm rope, and we took some BIG drops on those, trusting it with your life. Why is marine rope different?

I bet you didn't belay off a single anchor I think there are the obvious things like the risk of halyards parting, splices pulling apart, etc. which shouldn't happen with climbing ropes because they're not spliced, and should be inspected regularly (OK, even informally when you're coiling the rope up / flaking it out) and the use of pulleys, shackles, etc. in dubious condition as part of the rig. To be honest if the halyard runs inside the mast, and you've tied it off as it exits the mast (rather than rely on jammers, etc.) and use knots to attach (rather than shackles / spliced eyes) then it should be pretty bomb-proof. Less obvious is that if a 'Prusik' knot (as a generic term) slips, the heat generated can fuse the loop together, or melt through it. Probably a remote possiblity, but worth guarding against with some sort of back-up.

I can thoroughly recommend Nigel Shepherd's "A Manual of Modern Rope Techniques" for a full discussion of ascending ropes, safety, etc.

0.02p

Andy

 

[agurney]

Similar to most of the above - on one halyard I have a prusik to the bosun's chair and another to stirrups for my feet. Stand up/sit down is easy going both up and down. Having them on the same halyard means it is easy to slide the upper knot because of the tension in the rope. For insurance, I wear a safety harness with a third prusik on a separate halyard.

The line with the prusik should have a smaller diameter than the rope you are attaching to.

 

[dur]

On another note... I don't understand why there's a need for safety lines...

My lad was up the pole one time and I asked him to have a check around while he was there. He discoverd a shackle with the pin all but out. Then he realised that it was the peak halliard and he was hanging on it. I lowered him down very carefully!