Twin Vs. Double Ropes

[shaoleung]

So, are they interchangeable? Can you use ropes rated as Twin ropes as doubles?

[Alpinfox]

You COULD, but you shouldn't.

 

Twin ropes are not rated to take a fall on a single line.

 

 

[shaoleung]

That's what I hear... is there different construction? They're both kern-mantle. I guess what I am wondering is, is this a marketing thing or a real concern?

 

The reason I wonder, is that I'd like to get twin 60m ropes, but I'd like the option to use them as doubles for the not-so-direct routes.

[TrogdortheBurninator]

There are lots of ropes rated dual (Twin - Double/Half) and triple (Twin - Double/Half - Single). Buy those if you want options.

[Alpinfox]

guess what I am wondering is, is this a marketing thing or a real concern?

 

 

I don't think the UIAA really gives a shit about marketing.

 

Twins and doubles are both kernmantle, but twins are thinner and haven't passed the tests for UIAA approval for # of falls, breaking strength, etc on a single line. They will be more prone to cutting over edges as well.

 

I've used a single skinny line for easy stuff, but I'm not going to recommend that to anyone else.

 

I think Trogdor's advice above is very good.

[shaoleung]

Roger that. Thanks for the wisdom... I only found the Beal Joker as having multi-ratings... $200+ each for 9.1mm ropes. That purchase may have to wait.

[TrogdortheBurninator]

ropes arent cheap. i think the metolius ropes are twin/half.

[JosephH]

There was a similar conversation on rc.com recently and the quote below is my post from that thread. Also, Tuesday night I and a friend were working on a [currently] fairly dicey r/x-rated (due to sharp, fragile, and loose rock) FA and doing the reverse of the OP's inquiry - we were climbing on two Metolius 9.8mm single ropes using them as doubles. When a marginal piece blew at our high point I ended up taking a pretty substantial and glancing ride onto the wall below the roof we were attempting to push. Not sure how far a fall it was for sure until I get back up there next time, but it was into the realm of real business and falling on two singles used as doubles was not only completely fine - it was very comforting.

 

The reverse going the other way isn't the same sort of deal - I would never use a double as a single, or a twin as a double.

 

[Edited both here and on rc.com per catbirdseat's comment below - My oversight in the above is whereas using singles as doubles is fine, using them as twins is a bad idea and can introduce some ugly loads on your gear and produce a harder catch for you.]

 

The only three hard and fast rules I have about such matters is:

 

a) Don't use twins as doubles (unless dual rated as doubles)

 

b) Don't use a double as a single (unless dual rated as a single)

 

c) Don't use singles as twins (unless dual rated as twins)

 

Beyond that, over the years I've used and fallen on all manner, kinds, and sizes of single-rated ropes used as doubles and twins from 11's down to 9.8's and even combos such as 9.8/10.2 and 10/11.

 

Is it worth making sure your pro is either solid or screamered? Sometimes. Sometimes I don't care. Sometimes in FA territory where the rock fall potential is very high, or the rock is really sharp, I just want beefier ropes used as doubles or twins and I don't care the fall is going to be harder, or even possibly hurt a bit - oh well, at least I'll stop.

 

Maybe I'll beef or double up a placement under these circumstance, often I won't as my normal placements are usually pretty bomb this many years on. Sometimes I go out the other way and pre-slice screamers on an angle for a more gradual loading profile on really marginal gear that would normally only be considered aid placements. But typically those placements are marginel regardless if the ropes are being used within perfectly within manufacturer's parameters.

 

All in all, I consider discussions like this to be occuring within the margins of gear that's so good these days as to border on 'over engineered' (not that it's really possible to do when talking about some of today's ultralite gear, however). But from an old guys perspective, it's really a nitpicking, 'tempest-in-a-teapot' sort of discussion.

 

And Dingus has been mangled in enough interesting and unique ways on and off rock, and climbed with Brutus long enough, to where when he tells a story I always find it's worth listening too. As another old guy we don't always see eye-to-eye on everything, but I always listen and consider what he (and Brutus) have to say. I often learn something new that way or at least gain a different perspective on the issue. And even if I don't end up agreeing on the particular point under discussion, that new perspective can come in handy down the road in another context altogether.

Edited July 24, 2008 by JosephH

[catbirdseat]

Don't use two singles as a twin unless you want a hard catch. I've seen it.

[John Frieh]

Certification depends only on how the rope fairs in the test... it could be made out anything as long as it meets the following requirements: UIAA Safety Labels Dynamic Ropes

 

And many people climb on a single half rope especially on moderate ice and/or alpine.

[Bogen]

A cheap, reasonable solution would be http://http:/www.mammutusa.com/dyn_prodlist.php?k=88541

The Phoenix looks like great value, I have the genesis and like them.

 

The big problem with using a twin line singly is not the fall it will hold (within reason...), but rather its very low resistance to abrasion and rockfall.

 

The big problem with using any thicker ropes in a "twin" configuration is rope drag/ rope management, maybe a slightly greater safety concern than abrasion really.

 

I often only take a short, static 6mm when scrambling with kids or inexperienced friends. Nothing you would actually climb with, but a light, serviceable option to occasionally rope a nervous partner up. Its all a continuum from there, IMO, and subject to your own assessment of the days requirements.

Edited July 24, 2008 by Bogen

[JosephH]

Cat, you are correct and failing to mention not using singles as twins was an oversight on my part in the post above so I've edited it, thanks...

[jmace]

A single twin folded in half and used as a twin makes a perfect easy alpine setup.