Using 2 singles of different lengths as doubles for Multipitch

hey guys,

I made the poor decision to buy a 80m 9.5mm rope and my mate is thinking of getting a 60m of the same diameter. 

we were wondering if this would be okay to use as doubles for our upcoming multipitch road trip, I don't see any problems other than pulling extra rope on one side at the top of pitches and wonky rappels. we aren't going to rappel anything larger than 55m so a 60 and an 80 would do fine. I didn't do enough research and sort of jumped the gun buying an 80, so I might cut 20m off and use it as a gym rope, (my gym walls are only 7.5m high) then use the 60m left paired with a fresh 60 for double rope multipitch.

any thoughts, should I not bother cutting the rope?

I assume its fine to use 2 single ropes (9.5mm) as doubles as I hear allot of guides do this for groups of 3?

what is your thoughts and any advice on double rope setups is appreciated :)

Out of curiosity, have you tried using your belay device with 2 9.5mm thick ropes? As far as a double rope system, that's pretty thick and I can imagine it being a heck of a time paying out slack and taking in rope with ropes of that size 

Do not cut your 80m. There's no problem with rapping on cords of different lengths. Put the knot on the side of the longer rope, that way the shorter rope feeds through the anchor (less pulling overall). An 80m is useful for many climbing areas, for example Indian Creek and or Namaste wall at Zion. It'll be an important part of your "quiver" of ropes when you need it. 

Many multipitch climbs can be rappelled with a single rope, a 70m often allows you not to haul up a second rope, this is even more true with an 80m. 

The 80m will kind of suck for short pitches because it's a lot more like to pull in (and manage) before belaying up your second. 

Don't use these ropes as "doubles" for ascending. Twin and half ropes have elongation and impact force profiles specifically for that use. Just use one rope and keep the other in the follower's backpack. 

Ross Todd wrote: any thoughts, should I not bother cutting the rope?

Not unsafe, just annoying. On rock guide courses they constantly say to bring a 60m and that a 70m would make it annoying for the person guiding. Just use your rope as-is and pull more up.

I assume its fine to use 2 single ropes (9.5mm) as doubles as I hear allot of guides do this for groups of 3?

When guides do this, they only get a belay on one strand. If you get a belay on both then you'll get less stretch than if you were using just a single rope. Stretch helps absorb force so your body doesn't get wrecked when you whip. Consider tagging the long rope and not clipping it. 

what is your thoughts and any advice on double rope setups is appreciated :)

Know the difference between half and twin rope systems. They're both double rope systems. Be clear with your language and know the benefits and limitations of each. 

There’s no wrong answer here.  But…..

 In general, you have an Albatross— a rope that’s too fat and too long for most of your applications.   Personally I’d do what you suggest, chop off 20m and have 2 more “useful-to-you-now” ropes.  Sure you might have use for an 80 at some point, but I guess I’ve learned over the years that for maximum satisfaction, it’s typically best to only bring the bare minimum of what’s best for the climb at hand, not the possible climb in the future.

Adam Fleming wrote:

Not unsafe, just annoying. On rock guide courses they constantly say to bring a 60m and that a 70m would make it annoying for the person guiding. Just use your rope as-is and pull more up.

When guides do this, they only get a belay on one stand. If you get a belay on both then you'll get less stretch than if you were using just a single rope. Stretch helps absorb force so your body doesn't get wrecked when you whip. Consider tagging the long rope and not clipping it. 

Know the difference between half and twin rope systems. They're both double rope systems. Be clear with your language and know the benefits and limitations of each. 

just for clarity, its a sport multipitch (bolted protection) on a double (or half) rope system. so ill be clipping each rope individually into protection in an alternating fashion. If I whip I'm only going to be caught by the rope that's clipped to the nearest protection. since ill only fall on one rope I assume the forces will be the same as in sport climbing on a single? really the double rope system is just there for the long 50m+ rappels that you get in France and I cant be arsed lugging another 60m in a backpack. I don't trust the idea of using a pull chord either as if it gets stuck after the other end is away your basically screwed.

you don't think I should just cut the 80m to have a nice gym rope and a neat 2 60s?

Why don't you just belay on one rope? (the other one doesn't go through the belay device) And only clip to the one rope. It will be easier for your belayer. Have the leader trail the second, unused rope or the follower carries it in a pack.

Mark Pilate wrote:

There’s no wrong answer here.  But…..

 In general, you have an Albatross— a rope that’s too fat and too long for most of your applications.   Personally I’d do what you suggest, chop off 20m and have 2 more “useful-to-you-now” ropes.  Sure you might have use for an 80 at some point, but I guess I’ve learned over the years that for maximum satisfaction, it’s typically best to only bring the bare minimum of what’s best for the climb at hand, not the possible climb in the future.

yeah I think I might just give it the chop. In Europe it seems though the use use of double (or half) ropes is sort of needed to make the large rappels and 60m doubles are reaching the maximum of what you need, I think the 80m wouldn't be useful for much and more of an annoyance. The thicker diameter sort of makes me feel safer as well with rock abrasion and what not but yeah it might be hard to belay, ill have to test it out.

Tie into the middle of the 80 if you can make 40M pitches and raps. 

Ross Todd wrote:

just for clarity, its a sport multipitch (bolted protection) on a double (or half) rope system. so ill be clipping each rope individually into protection in an alternating fashion. If I whip I'm only going to be caught by the rope that's clipped to the nearest protection. since ill only fall on one rope I assume the forces will be the same as in sport climbing on a single? really the double rope system is just there for the long 50m+ rappels that you get in France and I cant be arsed lugging another 60m in a backpack. I don't trust the idea of using a pull chord either as if it gets stuck after the other end is away your basically screwed.

you don't think I should just cut the 80m to have a nice gym rope and a neat 2 60s?

Assuming you only fall less than one bolt length, yes, what you said is correct. But how often does that happen in practice? Once you go below a second bolt, then you're being held by two ropes with increased force. It's feasible on gear-protected routes, but I still don't endorse using a rope only rated as a single rope as a half-rope (nor do I endorse using one rope rated only as a half and or twin for belaying a follower).

Why bother having to think about which rope to clip and make the belaying significantly harder? Just tag the second line. You're making this more complicated than it has to be. Like others said 9.5mm is not typically a diameter people climb with double rope systems. Just because you can, doesn't mean you should.

I don't think you should cut the rope, but it sounds like you do! An 80m is significantly more valuable to me than a 60m and a 20m, but your situation sounds different. I would just buy another 60m or use a tag line (rig the raps so you're pulling the dynamic line, not the tag line).