Double ropes, twin ropes, and half ropes?

[Rodchester]

Ok...let me put this one out there.

Last night I was in a gear shop, not REI, and asked a counter-jockey what exactly the difference was between a double rope and a twin rope and a half rope.

He told me there was no such thing as a double rope, just twin and half. He then went into an explanation about how "ice climbers" use one and rock climbers the other. He never could explain the difference between the actual ropes, just whether you clip one or both ropes into your pro. He did say that they ropes are tested differently.

When I told him that the Maxim web site simply called their ropes "double ropes" he seemed to indicate that I didn't know what I was talking about.

(See www.newenglandropes.com)

He informed me that most climbers never talk to the manufacturers, so they don't know about ropes. He however, was an expert because he was trained by manufacturers. (I kept a straight face)

Now this thread is not to slam on counter-jockeys and gear shops at all. I want to know what you think the definition of "double ropes" versus "half-ropes" versus "twin ropes" is and what are the actual physical differences, if any.

Also, are there any good resources on the web that actually discuss and define the differences?

Well go at it and lets please try to keep the crap out.

Start your own thread if you want to cap on counter-jockeys.

------------------

Have a nice day.

[Doug_G]

The way I understand it there is no difference between a double and a half rope. When you use two half ropes together it is a double rope. Twins are another type of double rope system but when most people talk about using double ropes they are usally talking about using 2 half ropes. There are two primary differences. The first is how you use them, alternating gear vs. clipping both ropes into the same piece. The second are the specs. Half ropes usally fall into the mid 8mm range, where twins range from mid 7mm to low 8mm. Half ropes and twins are tested differently, so if your going out to buy new ropes keep that in mind. The specs between half ropes and twins are usually very differnt.

[speed]

This is my understanding:

Double Ropes: Generally in the 8.6-9.0mm range. These are also called half ropes. Designated by a "1/2" on the end of the rope They are used together however, the leader generally alternates clipping each rope (i.e. you don't clip each rope into each piece of pro). The UIAA test for this is 1 strand at 55Kg (versus 1 strand at 80Kg for single ropes). I've used this setup in both rock and ice.

Twin Ropes: Generally a bit smaller in diameter than doubles (low 8's). Designated with an infinity symbol on the end. They are used together as if they were one rope, both ropes are cliped into each piece of pro. The UIAA test is 2 strands at 80Kg (basically the same tests as a single rope, just with both strands). I have never used this setup, I prefer either a 10.5 single or doubles.

Despite the fact the "most climbers never talk to manufacturer's" I would suggest checking out the websites for several of the rope companies. Most of these sites are chock full of information. Plus they have links to e-mail address to send any questions to. I have e-mailed Metolius several times and always received an informative response.

Climb on!

speed

[forrest_m]

There was a pretty good discussion of this topic a few months back, here's the thread:

http://www.cascadeclimbers.com/ubb/Forum9/HTML/000013.html

[Rodchester]

But can anyone tell me why you clip the double or 1/2 ropes seperately and the twin ropes through the same pro? What happens if you clip both through the same pro on a double or 1/2 rope set up?

Is the only difference size? In other words is it decided on by the ropes diameter?

and testing?

[Smoker]

Originally posted by Rodchester:

But can anyone tell me why you clip the double or 1/2 ropes seperately and the twin ropes through the same pro? What happens if you clip both through the same pro on a double or 1/2 rope set up?

 

Basicly when you clip both ropes (double) into the same piece of gear you have increased (doubled I believe) the amount of force on the system in a fall situ. Instead of the single strand stretching and soaking up load, both strands are loading at once and not stretching (elongating) enough to be dynamic.

 

Is the only difference size? In other words is it decided on by the ropes diameter?

 

The difference between single,double and twin lines is in the uiaa/cen drop tests. I am not enough of a gear head to be able to quote the individual tests. Sterling Rope has the test data on their web site.

Smoker

[This message has been edited by Smoker (edited 03-23-2001).]

[Rodchester]

Smoker,

What is the address for Sterling's web site?

[forrest_m]

The difference is *not* just the diameter of the ropes. Of course that's part of it, and twins are usually thinner than even the thinnest half ropes, but not by that much. The way I understand it, twin ropes are formulated (through different types of nylon? weaving? relationship of core and sheath? only your rope engineer knows for sure) to be much stretchier than an apparently similar half rope, even if they have similar diameters. That way the impact force of both twins together (totalling about 16mm in total diameter) is still within acceptable limits while giving greater resistance to being chopped.

In contrast, the half ropes are each individually designed to essentially function as a single lead line, with the other as a "backup." Thus, clipping them both (i.e. twin technique) can lead to unacceptably high impact forces.

The thing to remember in wading through all this stuff is that the big danger is impact force - none of these ropes is likely to *break* under a fall, but mixing and matching technique (i.e. using half ropes for twin technique) may boost the forces outside the range that the rest of your climbing gear (harnesses, carabiners, your body) is designed to deal with.

[Guest]

go to www.google.com, type: double rope technique and look through the result set. The answers to some of the questions are quite good. I couldn't find a single site to contain "all you need to know" info. Also try: twin rope.

I have the same understanding as what Forrest posted. That's why manuals say that only clip doubles together on a bolt.

[This message has been edited by rafael (edited 03-23-2001).]

[Rodchester]

My understanding has always been that if both double ropes are clipped they will create a greater forfce on the pro and could either pull the pro, the biner, or the draw.

Where with "twin" ropes are designed to work in unison and will not create the impact force on the pro.

I think forrest_m is close in saying that it is the way "twin ropes are formulated (through different types of nylon? weaving? relationship of core and sheath? only your rope engineer knows for sure) to be much stretchier than an apparently similar half rope, even if they have similar diameters."

I really would like to hear from an engineer on this, or at least a rope rep. I sent an e-mail to a few companies, we will see if they respond.

Thanks for all of the beta and opinions. Keep them coming.

[tomrogers]

The UIAA standard requires that even if a double rope(old school)is used in a twin configuration that the impact forces still be less then or equal to the minimum requirements of a single (full rope). If you pro is good enough for a single rope then it should still be good enough for a doubled double rope. They say you should still clip with different biner though as to not burn the sheath. But this is another arguement.

cheers.

[Guest]

 

Here's some web addresses and data I culled.

Sterling's got the lightest, and the ICE FLOSS is a twin rope not a double rope. Sterling has a very happy maximum impact force but Blue Water is the worst.

Blue Water http://www.bluewater-climbing.com/

8.0mm twin ICE FLOSS (37m, 60m)

40.8g/m

10.1kN

13 falls

7.8%

8.6mm half EXCELLENCE (50m, 60m)

47.7g/m

6.3kN

9 falls

7.6%

 

Maxim http://www.neropes.com/maxim_climbing/default.htm

8.5mm half

48.2g/m

6.02kN

8 falls

7.6%

 

Sterling http://www.sterlingrope.com/2000/climbing/index.htm

7.6mm twin ICE THONG (37m, 50m, 55m, 60m, 100m)

34.1g/m

7.4kN

12 falls

8.8%

8.8mm half HALF ROPE (37m, 50m, 55m, 60m, 100m)

55.9g/m

6.5kN

12 falls

8.9%

 

Pigeon Mountain Industriees - PMI http://www.pmirope.com/sport/Default.htm

8.1mm half ,may be used as a twin VERGLAS (60m only)

40.9g/m

8.4kN twin, 5.8kN half

12 falls twin, 8 falls half

8% twin, 10% half

8.6mm half FUSION (60m only)

48.4g/m

5.9kN

17 falls

9%

 

Beal http://www.bealropes.com/english.dir/gear.html

7.9mm twin TANDEM

41.0g/m

7.5 kN

14 falls

8.3mm half LEGEND II

45.0g/m

4.9 kN

10 falls

8.6mm half COBRA II

48.0g/m

4.8 kN

17 falls

 

Edelrid http://www.edelrid.de/e-index-eiskl.htm

7.8mm twin DYNALOC (any length)

39.0g/m

21 falls

 

 

[highclimb]

twin ropes:

better for pure ice climbing or routes in the mountains that contain a fair amount of near vertical ice.

this i sbecause there are two ropes that are cliped into the peice so there is almost no chance of a total system failure and it provideds more protection from falling ice and or rock. if one rope cuts you still have one. your not stuck out on a ledge on the north buttress of Mt. hunter with night creeping closer(knock on wood).

Half ropes:

can be used for anytype of climbing whether its alpine ice/rock, trad rock, sport rock. they reduce rope drag, put less force on your pro when you take a whipper and they are light

the PMI fusion or verglas would be my choice they combine awsome strength and durability and they are light and have no sheath slippage.

 

Aidan

[This message has been edited by highclimb (edited 03-24-2001).]

[Alpine_Tom]

This topic has been worked over fairly completely, but as the son of a reference librarian, I can't help quoting from an authority -- (it's in print, so it must be true!)

This is from Duane Raleigh's "Knot's & Ropes for Climbers"

"Single ropes are those designated by the UIAA as safe for single-strand use...Single ropes come in diameters from 9.8 to 11 mm. Sport climbers, to whom every ounce is the enemy, typically use 9.8-10mm ropes...

Double Ropes are those that you must use in pairs, although you don't need to clip every rope through every point of protection. Rather you can alternate clipping the ropes, an appreciated feature that reduces rope on winding and traversing routes. You'll find double ropes in the 8 to 9mm range. Double ropes are ideal for ice, alpine, and mountaineering, where you typically need two ropes to rappel the route and carrying two heavy single ropes doesn't make sense... All double ropes have the number 1/2, surrounded by a circle, on the rope's whipped ends.

Twin ropes are the most dysfunctional of the lot, and I've never been able to rationalize a place for them. These 7 to 9mm lines are used in pairs like double ropes but differ drastically, as both strands must be clipped to every point of protecion. In my eyes, cliping both ropes robs them of the great advantage of double ropes - that of alternating clips to minimize rope drag. Also these small-diameter ropes are snag and tangle prone, and I can never seem to keep them orderly. Still, twin ropes provide the highest safety margin of all ropes and are the lightest combination possible, making them appealing to a few extreme alpinists...

Twin ropes have the number 2 surrounded by a circle, on the rope's whipping. Don't confuse twin ropes with double ropes; they are similar but not interchangeable."

 

[Guest]

I have used all 3 systems and they all have their place. The best of all would probably be a double but in this world of Grigris it can be hard to find belayers who are capable of correctly belaying a single. There is almost twice the amount of work belaying a double system( half ropes), feed one rope while holding the second, it helps if you belay directly off the anchor and this is what the German guys I climbed with did. They also weigh quite a bit ( 13 to 15) pounds. Twin ropes are much easier to belay and weigh only a little more than say a 10.5 of the same length. Yeah they tangle more but thats life. They worked pretty well on stuff like the Regular route on Fairveiw in Tuolume or Snake Dike. Later.

[Rodchester]

Good info everyone,

But what seems to be missing is the properties of the ropes...is there a difference? Many of you (forrest_m) have alluded to differences, but no one has stated any clearly.

I am seeking a more diffinitive answer, less about the technique, pros and cons, and more about the actual rope.

I sent e-mails to many of the manufacturers, we will see if any respond.

Thabks for all of the input!!!

------------------

Have a nice day.

[Colin]

I have recently come across the smallest diameter twin rope that I know of. According to Gripped magazine (Canada's Climbing Magazine), Mammut is now making a rope called the Twilight which is 7.5 mm and holds 19 UIAA twin falls. The high strength and small diameter is the result of teflon-coated fibers, which I assume work by decreasing the friction inside the rope.

[gregm]

Whatever ropes you have and however you decide to use them given a particular situation never mix double and alternate clipping on the same pitch. If you take a fall it will create enourmous friction between the two ropes and can burn through them.

[scott]

.

[This message has been edited by scott (edited 05-23-2001).]

[Thomas]

In response to the question as to why it was bad to clip double (half) ropes to the same biner;

The answer (as I understand it) is that if you start out the pitch clipping separate (double/half) ropes to different pieces of pro, and then clip both ropes to a single piece, there will be different amounts of slack in each rope. If you were to fall at this point, or above for that matter, then the individual ropes would pull through the 'biner at different rates of speed. The friction of the two ropes against each other can damage the ropes significantly.

I have clipped both (half) ropes to the same pieces on runout ice pitches, however I think that you should be consistent in your clipping style, so that the ropes experience similar conditions during a fall if they are clipped to the same piece. But that's just my opinion.....

[Guest]

Rodchester, I'm curious why you're so curious 'cuz maybe I should be more curious myself!? Having worked in various manufacturing industries I would opine that few of the people working at a 'rope' manufacturing plant would be able to accurately describe the technical design differences (if any) between twin, half and single lines. If would be groovy if you could connect directly with a Materials Engineer working in the industry.

Alpine Tom quoted a good referenece, but it's already over 3 years old…. single's are easily available much smaller than 9.8mm, currently a 9.4mm single is available and by the end of this year I expected to read marketing about 9.1mm/9.2mm singles coming soon.

And Don G said a pair of twins weighs a little more than a 10.5mm, maybe in some cases, but not in most. The Sterling ICE THONG twins weigh together less than most manufacturers' 9.8mm singles….. together they weigh 68g/m.

Colin, I could not find a quick internet reference to this new twin rope from Mammut. What I did find was

Mammut

8.0mm twin GEMENI

43.0g/m (42.0g/m)

9.8kN (9.6kN)

16 falls (19 falls)

5.6% (5%)

I found both sets of values online.

 

[Rodchester]

Curious....because I have heard opinions, stated as fac,t from sooo many people that have each varied sooo drastically on the topic, and none have been able to back it up?

I am just not the kid of guy who takes things like this as gospel because someone, everybody, says so.

1/2 ropes are supposed to clip seperately they say...yet Sterling ropes says that their 8.8, which they call a 1/2 rope:

"is designed to be used in pairs and clipped through protection either together or alternately."

Does this mean I can do that with all half ropes? Most say no...but can't show me why.

Sterling ropes says that their "7.6 is designed to used in pairs with both ropes clipped together through each piece of protection." a twin rope, yes, but what if I clipped them seperately?

Just curious...yes.

Surprised that climbers can't answer this one...maybe even concerned.

I agree it would be great to hear from an engineer. I sent out quite a few e-mails seeking info form manufacturers. I will let you know what they say, if they say that is.

Isn't there anyone out there who knows this?

[speed]

I've heard this too (cliping into separate biners on a single piece). In fact John Long's book recommends this for the first few pieces from the belay. His rational is to safegaurd against high impact forces generated when a leader falls with so little rope out. Makes sense to me.

speed

[dan_e]

If twin ropes can be clipped into a single biner, than why can't you do the same with double ropes? The sheath can't be that much different. I use BW Ice Floss for ice climbing (always clipped together) and BW Excellence for rock (clipped together or separate). Does anyone have any hard evidence that this is a bad idea? Something from a rope manufacturer or testing from the UIAA?

[Rodchester]

Dane has hit the head of the nail...does any one have any hard data or beta that is backed up by manufacturers or actua; engineers, tests, etc.?

Clearly there are differences, what exactly are they?