Using "dynamic" rope as a safety line

[allene]

I got the bright idea of getting some mountain climbing dynamic line to use as a safety line when climbing my mast. I like the idea that I can have this little gizmo that I put a carabiner on and it just follows me up and will grab me if my main setup fails without cracking my ribs from the lack of give. (I pull myself up without anyone on deck). But I find that this line has something just under 10% stretch against just my weight. So if I want any protection when at the top I run it up the mast, through a block, and back down. Now I have 80 feet of line which will stretch 8 feet if I just hang on it. I would guess I could get reasonably high and yet still hit the deck if I fell. But if I use a single section, there is no stretch when I am at the top. OK, so I could tie two lines together and have some low stretch line that I actually put the ascender on and have a 40 foot section of the dynamic line going up to attach to that line at the top. That gives me a constant amount of line I would be falling against.

Does anyone have experience with this kind of line and if so what is the correct way to rig it for this application?

Here is a picture of the little ascender. When you pull up, it freely goes up the safety line without having to take your hands off the main line. I really like that part of the setup.



Allen

[allene]

I just read another option I had not considered and that is to pre-tension the line so that you won't hit the deck from the spreaders. Humm, still wonder if there is a "best practice" way to do this.

[Clyde Jenkins]

Rather than hauling myself up and requiring a safety rope, I use a serviceable halyard to hoist a climbing rope. I climb the rope using a single rope technique from caving. I have two Petzl ascenders, a climbing harness with a chest rig, and a foot loop rig. If I have a helper I have them tail a safety rope, usually another halyard.

The technique I use comes from the book "On Rope" by Bruce Smith and Allen Padgett. In particular I use "frogging".

Setting up this system and getting rigged up myself is not fast, but it is secure and I'm convinced it's safe. On Rope discusses a variety of techniques and has plenty of discussion about safety.

As for a serviceable halyard, I always inspect the line that supports my climbing line. If it looks frayed or is wire to rope and has meat hooks, then the boat owner gets to replace it before I climb.

My actual climbing rope is an ancient three strand mountain climbing rope (from the late 60's) called Goldline. It's been carefully stored and never abused and has plenty of life left in it. If I ever discard it the replacement will be a more modern climbing line.

The nice part about this setup is that you should never be at risk of a dynamic fall, i.e. a fall of any distance. Check it out.

Clyde

[Brion Toss]

Hello,
Dynamic rope was developed for the long leads that climbing entails. The idea is that you might have to climb some distance, putting slack into your belay, before you can establish a secure location. This means that if you fall, it is likely that you will fall a significant distance before the line takes your weight. A static line's shock load can maim or kill.
But in yacht rigging -- and many other climbing applications, there is usually no reason ever to have a slack line, or a fall of more than a few inches. Hook that ascender carabiner directly to your harness.
Anyway, I also hoist my climbing rope on one of the boat's halyards, and either have a crewmember or an ascender on the safety. I pull myself up using a ratchet block.
Fair leads,
Brion Toss

[benz]

Hi Allen,

I second Brion on not using stretchy line. When climbers "fix" lines on a cliff, they always prefer static lines, the reason being that when you "Jug" a dymamic line, there's a lot of bounce. Sometimes if you're starting at the end of a 200-foot rope, or worse, two 200-footers tied together, you have to jug for fifteen minutes before getting both feet off the ground, because they stretch so much. That little Petzl Tibloc in the picture will work best with a nice piece of 3/8" or 7/16" double braid.
Best,
Ben

[allene]

Seemed like a good idea in the store. Now I have 200 ft of useless rope that I foolishly cut in half.

[benz]

No Allen, you have two lovely 100-ft lengths of very useful line. Sacrificial anchor snubber? Spare dockline? Sail tyers? There's always tons of uses for good line. But condolences on it's intended purpose not working out.

[allene]

Originally Posted by benz

No Allen, you have two lovely 100-ft lengths of very useful line. Sacrificial anchor snubber? Spare dockline? Sail tyers? There's always tons of uses for good line. But condolences on it's intended purpose not working out.

REI has a 100% satisfaction guarantee and 200 feet of used dynamic rope with Brion's favorite knot in the middle.