UKC

I'm looking at getting some semi-static rope for rigging bottom ropes. It will probably be used the most in the Peak District and on Southern Sandstone.

What length should I go for? I already have a 60 m dynamic rope, so I don't want to carry a lot more.

Also, I've seen some recommendations to climb on semi-static, not dynamic, on sandstone, to avoid damage to the rock. If I use rock protectors and make sure that the rigging rope hangs over the lip of the crag, can I climb on my dynamic rope?

Thanks

(semi) static ropes are perfect for anchor building, rigging and rappel ropes.

for climbing, the normal dynamic rope is still useful.

albeit (semi) static ropes can be used for top-roping, and often are as they wear less than dynamic ones (clubs, walls etc.). for normal peeps, makes no sense though, so simply use your dynamic one.

for lenght, I'd guess 30 to 40m (and about the same for dynamic one)... but those local should give you more idea than my brief few day stint on grit.

I use lengths of about 12 to 15m. Usually works well for most belays in the Peak.

I am using my dynamic for top roping (belaying from above)

But, as neither me or my usual climbing partner are leading yet, I need to be able to rig a bottom rope so we can belay from the bottom of the crag, just like you'd do in an indoor wall. My understanding is that semi-static should be used to rig the anchor at the top of the crag, and then run your dynamic rope from that anchor through the screwgate carabiner that the anchor is equalised on.

It is the length of this anchor-rigging rope that I'm interested in - I don't intend to climb on semi-static rope.

I use lengths a little longer than Jimbo i.e. more like 20m. You'll generally need less for natural gear but I find some stakes I use to be quite far apart. A few medium to long slings can help here too. 

17m when bought - soak in the bath and you get 15m...

I find 10m is enough for s/sandstone.

Long slings could be carried just in case you come up short, less weight and bulk than loads of rope. 

<Ever so slightly off-topic but bear with me...>

You really don't you know.  Need to, that is, though I can see why you might want to. 

Just because you're not leading, that doesn't mean you can't belay from the top.  (Instead of climbing just like you do at an indoor wall, climbing just like you do if at least one of you is leading the routes.)

Rig the belay, one of you heads down to the bottom.  Climb, swap places, repeat. 

For just the two of you, climbing as peers, it might often make more sense to do so, as it means you would ordinarily top out rather than lowering off and finish the climb with you both at the top.  If you intend to start leading at some point, the experience gained might be more valuable too.

Most of the time 'bottom roping' on gritstone is only really necessary if you're there with a group of kids or somesuch.

Edit to add:
Back on topic - I'd echo the above.  12-15m should be ample, 10m is plenty most of the time.  But you may as well keep it short and belay from the top if you need more, using your lead rope (which at 60m is way, *way* more than you need for the grit) to rig as required.

There's a few reasons I don't want to keep belaying from the top, although I know how to and would probably be useful for when I (hopefully) start leading:

1. Living in London, the closest/easiest to get to crags are sandstone, so I would have to belay from the bottom anyway

2. I find it more awkward and harder to belay from the top - I want to go climbing, not constantly have a shoulder workout

3. Most people I'm likely to climb with at this stage will already know how to belay from the bottom, so I won't have to teach them a different way of belaying and then constantly worry about whether they've got me or not

4. I don't want to constantly run my dynamic rope over the lip of the crag lowering people, especially on grit - yes, we could just walk down and swap places, but that's just a lot of faff

1: Yep, fair enough.  I'm local to the Peak, so am primarily talking about that.  As I said, I can see why you might want to "bottom rope", but in the post I was replying to you mentioned that you need to.  On the grit you don't need to.

2: I think you must be doing it wrong.  There is no 'shoulder workout' required.

3: I took it from the above that you were climbing with a regular partner as peers.  If you're taking beginners climbing that is different.

4: Again, I think you must be doing it wrong.  It is no more faff than bottom roping: you rig the belay together, one walks down and climbs, tops out, second walks down, climbs, tops out.  Re-rig the belay on the next route together, rinse and repeat.  The vast majority of single pitch grit routes have a quick and convenient descent route close by. Routinely lowering off and/or spending ages 'working' a route that is too hard for you are poor form really.  Bordering on the ethically questionable on the grit, just plain unacceptable on Southern sandstone. 

Please note that on the Southern sandstone you should most definitely be topping out not lowering off, even whilst belaying from the bottom.  There's a code of practice for SS you can download here: https://www.thebmc.co.uk/access-launch-updated-version-of-the-sandstone-cod...

30m is what I carry as a rigging rope in The Peak District.

When a semi-static rope is made it is treated with numerous chemicals to protect the rope during the manufacturing process. With most semi static ropes it is best to soak/wash them first before use, this removes these chemicals and forces the outer part of the rope (mantle) to contract and tightening it around the core (Kern) of the rope when it dries. This will reduce sheath slippage in the future and make for a better abseil rope. This contraction, however, will cause the rope to shrink by anything up to 10% so be wary of this if you buy a 50m rope for a 50m abseil.

Semi Static Ropes are graded into two types. Type A and Type B. Type A are tested with a higher load (100kg) than Type B (80kg) ropes. I only ever buy Type A ropes.

Interesting. I've been looking at semi-static ropes online, and this is the first time I'm hearing about the two different gradings. Could you please give an example of Type A rope?

It looks like the consensus is that 12-15 metres of rigging rope should be enough to start with. I'm gonna go for 20 metres just to have a little bit extra.

Thanks all for chipping in, it's much appreciated

Type A is anything you are likely to buy.

Type B is a lower spec, less durable than type A and intended primarily for use in commercial/industrial rescue kits, emergency evacuation kits, stuff like that.  In these situations it's essentially single-use, either it will sit in a fluorescent bag until it reaches it's 'sell by' date and gets retired or it will be used in an emergency and retired immediately afterwards.

Semi Static ropes will always be marked Type A or Type B.

Example of a Type A

https://www.alpinetrek.co.uk/tendon-pro-work-105-static-rope/  £69.95 for 40m

Example of a Type B

https://www.decathlon.co.uk/canyoning-rope-9-mm-x-40-m-id_8394058.html  £52.95 for 40m