Extra Rap Cord

[tlinn]

I have a lightweight 9.2mm rope that I like to climb on in the alpine. What kind of static line should I buy in case I need to retreat off a climb. I'm thinking of safety but also weight. Also, is there a problem rapping off of two ropes that are of very different thicknesses?

[Stephen_Ramsey]

6mm static works. You might want to make sure it is a bit longer than your dynamic rope (maybe 3m longer?). But you don't get anything for free; 6mm cord is super light, but it tangles horribly and feels a bit sketchy any way you rig it. I have often rapped on 8.5mm + 6mm tied together, and have not found it to be too terrible. Generally I rig a pussik to the 8.5mm rope from the anchor, so the first rapeller avoids any rope slippage. Then before I rap, I remove the prussik and then make sure the knot is on the 6mm side of the anchor, and not on the 8.5mm side. Then I use an extra biner and an autoblock back-up to make sure the rap is super controlled. A bit of extra tension on the thin cord seems to prevent rope slippage from the differential friction through the belay device.

 

I wouldn't recommend using an EDK to tie the two cords together. I've used double-fishermans and also rewoven figure 8 (with a backup knot), instead of the EDK. So, some care is recommended to avoid getting a stuck rope.

 

If there is a chance of rockfall nailing your rap cord, you might want to consider using a rap ring and a really fat knot. This way, if the skinny cord gets cut, the knot wedges in the rap ring and (theoretically) you don't fall.

 

There is a fancier system to rap on a single 8.5mm cord with a 6mm retrieval line, involving a carabiner. But, it means a carabiner will be pulled down with your retrieval line, with the extra potential for rockfall and rope stuckage. So, I've been reluctant use it in the alpine. YMMV.

 

I haven't used this 8.5mm + 6mm system when it is super icy, so I don't know how sketch it would be.

[Bill_Simpkins]

I've never had a problem with the different thicknesses.

Make sure your static line is as long as your dynamic line stretched out.

[cj001f]

I've used a 6mm pull with a 8mm static no problem. Others have used smaller. Look into a bag to keep the pull rope in so it doesn't tangle.

[tlinn]

Great info...thanks a lot

[cj001f]

This is a cool cord bag - little heavy, but damn nice

[rock-ice]

What the best place to pick up a static line? Buy it by the foot?

[Jason_Martin]

I would pitch that before investing in a 6mm system that you should find someone with one of these systems and climb with them. There are definately people out there who get annoyed by the tangling issues and decide to go with something bigger.

 

Jason

[specialed]

Keep in mind though that a using a 6 mm to pull a larger diameter rope is a huge pain in the ass and is kind of scary and will suck if you plan on making a lot of raps.

 

A double rope system works a lot better unless you need to haul or something.

[Bogen]

I carry a 8.5 dynamic and 6mm static when I'm soloing and there is a lot of rappelling involved. I find that even a 6mm/10.5mm setup is easy to pull and tangles less than my double ropes. In scarier pulls, like when the rope might get caught up in shrubs or rubble, I actually leave the 6mm through the rap anchor and pull the thick rope. It's no different really than what supports you off a v-thread, but still scares me sometimes. Ropes come down like magic, though, If you pull the thin one, you have no ability to flip the knot around from a distance if it catches.