UKC

Time for a really noob question. My apologies in advance for this one.

So, I'm in possession of two ropes. Both are dynamic. Will the additional stretch in these ropes make rigging top ropes with them unstable or unsafe in any way and if not, what measures will I have to take when setting up the top rope to take proper consideration of the extra stretch introduced into the system by the presence of more dynamic rope than you may normally use?

I sorta feel like I'm missing a point here so I'd rather ask and look stupid than shrug it off and not take proper consideration of a factor I may not yet fully understand. Be gentle, peeps.

(Sorry for the previous post for any who saw it. I've had belays on the mind of late)

In reply to dl_wraith:

Rigging with a dynamic rope means that the rope will move a lot more and be less wear resistant so give very special attention to padding where ropes run over edges and make sure knots don't end up running where you don't want them to.

Obviously the more times you run the rope pack to the anchor, the less stretch you will have.

In reply to dl_wraith: If you must use dynamic ropes for rigging then you can forward tension the rigging ropes at the top of the crag. Set up your ropes at the top of the crag as usual but then attach a prussic to the rope as close to the edge as you can get a peice of gear - pull the stretch out of the rope - so the prussic hold the tension in the rigging rope.
Don't forget edge protection - not just for the edge - but ensure that the ropes don't run directly over any other sharp edges.

if you are using really skinny ropes (eg halfs) just keep reminding yourslef that the, now, shoe lace thin peice of cord is rated to hold your weight.


Marc

In reply to mp3ferret: meant to say - if the top of the crag is pretty much featureless - then an upside down nut, etc somewhere near the top of the crag also works.

In reply to dl_wraith:

Rigging a top rope (belayer at the top) with dynamic rope in the belay is the norm. If you're <10m or so from the anchors then just get them nice and snug once you're sat a few inches from the edge, you'll be pulled to the edge but not over it by a fall. If they're longer runs than 10m you need to adjust the tension/your position a little to make sure you're not pulled over on stretch.

A doubled run of dynamic doesn't stretch much and there's typically one at least in any top-rope belay, use it for the long run if you can afford enough rope.

If you mean bottom-rope belay with a rigging rope and a climbing rope then the main problem is abrasion of the rigging rope, knot or rock where the rope runs over the edge. As already mentioned, doubling up the rope run reduces the stretch (multiple anchors have the same effect). Make sure your krab and climbing rope hang free over the edge. Protect the rope/rock with a bag or old carpet or a commercial rope protector. Make sure that your knots isolate the rubbing area so a (first) failure there wont be catastrophic.

Don't fall while rigging, tie in if need be, it only takes seconds.

Ask if you aren't sure, people are pretty helpful when they have the chance to be.

jk

In reply to jkarran:


I didn't make that particulary clear, did I? I did indeed mean rigging a top rope for a bottom-rope belay. I want to try and get my little group out on rock and I figured that setting up similar to what they are used to indoors would be a good way to increase confidence and ease them into it.

That said, the rest of youyr advice was sound too so thanks for that.

And yes, helpful people. I am finding that with climbers more and more and am extremely glad of it.

In reply to GrahamD: Thanks for the tip there, Graham. I'd sorta figured that the rope would move more but hadn't taken into consideration the effect on wear.

I'd be using a protector anyway and had already intended on double-runs back to my anchors (call me paranoid). Now I see why that would be a good idea anyway.

Thanks.

In reply to mp3ferret:

You know, I didn't think of using a prussic in the system. That sounds like a great idea! Thanks, Marc. I think i will experiment with that one.

And as for the ropes, I own a pair of 11MM ropes (one 30M the other 50M) and not a pair of 7 or 8mm half ropes. Having recently used a kind souls half ropes at a local crag, I know what you mean!

In reply to dl_wraith: raher than pre-tension the rope which sounds a bit of a faff just run more lengths back to your anchors. This will spread the load over more strands meaning less stretch in each. Should keep your knot from moving around and grinding to bits.

In reply to dl_wraith:

Also, where do you plan to do this?

If it is on soft southern sandstone, then rock wear is more of an issue. If it is on tough granite, then it really won't matter.

Most of the time, stingy climbers only buy dynamic ropes, and use these for everything, moving ropes from being climbing ropes to being ab ropes as they get older. Most climbers use their climbing rope to extend their belays. It's generally only leaders who take groups in a professional capacity who bother to buy static rope to use to set up top rope belays. Unless you are creating anchors that are very very far back, you really won't notice the stretch.

Have fun!

In reply to tlm: Gritstone quarries and crags around Chew Valley, the Wilton area and similar mainly. being Manchester based and the only driver in my group travelling too far can be a bit on an issue.

In fact, the first place I'll take them is Hobson Moor Quarry - good belay anchors, easy access to the top of the crag, some good beginners routes and not too far from my group or the roadway