The best rope? ;-)

[lostgravity]

Hi,

I'm thinking about buying my first caving rope and did some research on what's out there - I would appreciate if you guys could throw in your experience and opinions, I have tried to summarize what I found out so far. There was an earlier thread in this forum that pretty soon ended with "PMI Pit Rope" as the recommendation, but I thought I give it another try and get some more information on other rope as well...

Most of the rope types seem to be available in the "typical" sizes of at least 9 - 11 mm, and it seems to me that the discussion Nylon vs. Polyester can be very briefly summarized in "Polyester, less stretchy and bouncy, needs to be very well rigged and you shouldn't fall into it". That said, here is what I believe to have found out about North American and European static ropes so far, in arbitrary order and with disregard of their availability in the US (will be going to Germany soon, could buy some European stuff there):

<b>PMI PIt Rope:</b> only in 11 mm; durable, less bouncy than Bluewater or Bob & Bob

<b>PMI Maxwear:</b> different diameters available than Pit Rope, but similar properties (?)

<b>Bluewater II+:</b> durable, but bouncy; less stiff than PMI Pit Rope; the only one to withstand the American non-rigging technique ;-)

<b>Bob & Bob caving rope:</b> similar to Bluewater

<b>Cancord Nylon:</b> no idea

<b>Cancord Polyester:</b> more or less the only polyester-only rope that I'm aware of

<b>Roca espeleo:</b> good price/value ratio; semi-static (not sure whether this means it's more bouncy than the ones that call themselves "static"?); good to handle & knot

<b>Millet Spelunca:</b> very robust, very little stretch

<b>Mammut Protec:</b> excellent, but expensive

<b>Edelrid Superstatic:</b> about average, expensive

<b>Petzl Vector:</b> polyester/nylon fusion; 11 mm and larger only

<b>New England:</b> ??

Thanks,
David

[hank moon]

Generally speaking, if you plan to use the rope in the U.S. with other U.S. cavers, it'll probably see a good deal of IRT use, in which case a european style semi-static should probably be avoided. More below ("N/E" =no experience)

<b>PMI PIt Rope:</b> only in 11 mm; durable, less bouncy than Bluewater or Bob & Bob
The standard (white only)

<b>PMI Maxwear:</b> different diameters available than Pit Rope, but similar properties (?)
Same as Pit, but w/colors available

<b>Bluewater II+:</b> durable, but bouncy; less stiff than PMI Pit Rope; the only one to withstand the American non-rigging technique ;-)
Another good choice. Thick sheath for abrasion resistance.

<b>Bob & Bob caving rope:</b> similar to Bluewater
N/E

<b>Cancord Nylon:</b> no idea
N/E

<b>Cancord Polyester:</b> more or less the only polyester-only rope that I'm aware of
Good stuff (thick sheath), but have only used 8 and 9 mm diameters. Not the best rope for a beginner. Heavier than nylon when dry; lighter when wet.

<b>Roca espeleo:</b> good price/value ratio; semi-static (not sure whether this means it's more bouncy than the ones that call themselves "static"?); good to handle & knot
Eu-rope N/E

<b>Millet Spelunca:</b> very robust, very little stretch
Spelunca "reg" or Spelunca Vectran? N/E

<b>Mammut Protec:</b> excellent, but expensive
What is excellent about it? Mammut makes good cord in general, but haven't heard of this particular model. Is it the one with the new braiding technique?

<b>Edelrid Superstatic:</b> about average, expensive
Eu-rope

<b>Petzl Vector:</b> polyester/nylon fusion; 11 mm and larger only
Relatively bouncy, slightly thinner sheath than others (PMI, BW) so not as good for caving.

<b>New England:</b> ??
Excellent quality brand - might check out their KMIII Max (N/E)


http://www.neropes.com/techdata/kmiii_max.htm

[speloman]

I Own a Blue Water II+ 11mm and a New England 11mm and I love them. I also have used PMI ropes and like them too.

[jmo]

Hank - great post.

You might also want to check out the Petzl Vector Line. I've heard a lot of goog things about this rope.

http://store.karstsports.com/ropeve.html

[RescueMan]

<b>Petzl Vector:</b> polyester/nylon fusion; 11 mm and larger only
Relatively bouncy, slightly thinner sheath than others (PMI, BW) so not as good for caving.

Speaking of thinner sheaths. What do you, Hank, and others think about Sterling's claim that their very supple (and thin) 48-carrier sheath is actually MORE durable because each individual fiber is exposed less on the surface?

And, while we're at it, what do y'all think about their claim that their proprietary DryCore is more resistant to saturation than other ropes?

http://www.sterlingrope.com/2005/rescue_products_group.asp?pg_id=1

SuperStaticâ„¢

"Developed in 1993, this nylon static rope is still without equal. Two important and unique technical components are a 48-carrier sheath construction and DryCore™. This is what makes SuperStatic ropes incredibly durable and moisture resistant... There is no doubt that Sterling’s SuperStatic will outlast and outperform all other static ropes on the market.

This unique construction is what makes the rope easy to handle and deploy quickly and efficiently. Its smooth, firm sheath provides not only a quiet rappel and minimizes excess dirt build-up, but also allows the rope to pass through gear and equipment without vibration.

Perhaps the most important difference between Sterling’s SuperStatic and all other ropes is DryCore™. Only Sterling ropes have DryCore™, cores that are dry. This is an important safety feature. A wet rope is a compromised rope. "


- Robert

[Scott McCrea]

Speaking of thinner sheaths. What do you, Hank, and others think about Sterling's claim that their very supple (and thin) 48-carrier sheath is actually MORE durable because each individual fiber is exposed less on the surface?

And, while we're at it, what do y'all think about their claim that their proprietary DryCore is more resistant to saturation than other ropes?

I have no experience with the DryCore, so I can't be of any help there. But I do have an opinion the sheath.

At Bridge Day in 2000, Wm Shrewsbury rigged up some racks with temperature sensors and had rappellers use them at various speeds and styles. I don't know if he ever published his results, but he did give a presentation at the 2001 NSS Convention. The rope with the highest temp readings (significantly higher) was the Sterling HTP Static (polyester core) with the 48 carrier sheath. I don't remember what Shrewsbury's conclusion was, but mine is because of the smoother (less bumpy) sheath, there is more surface contact with the rack bars creating more friction/heat. It caused bluing/browning on one set of stainless bars. He also had the bottom 30' or so of this rope. It was very crusty and blue strips had melted and turned the rope blue.

In my testing with cutting loaded ropes, everything basically boiled down to 'thicker is tougher'. The thicker the rope, the harder it was to cut. The thicker the sheath, the harder it was to cut.

I think Sterling's claim of greater abrasion resistance is partly marketing hype. On some surfaces (like an abrasion wheel, round with rough surface), a smooth sheath may perform a little better. But if there is anything sharp, like an edge, I predict is will cut easier than a thicker sheath.

[hunter]

but mine is because of the smoother (less bumpy) sheath, there is more surface contact with the rack bars creating more friction/heat

Scott and all,
I've never used the rope in question but I'm a bit curious about this statement. Maybe I'm missing something but I don't think basic Physics allows this to work because as you rappel a certain distance, say 100ft, you will always dissipate the same amount of energy (assuming you don't hit really hard or change weight). What really changes is how the energy (heat) is dissipated.

It seems to me that more heat means you are either 1. going faster so it has less time to dissipate or 2. you are changing the dissipation.
I think scenario 1 would be likely if you have a slicker rope and scenario 2. would pop up the rest of the time.

hunter

[David_Campen]

I don't think basic Physics allows this to work because as you rappel a certain distance, say 100ft, you will always dissipate the same amount of energy (assuming you don't hit really hard or change weight). What really changes is how the energy (heat) is dissipated.

Exactly, if a 150 lb person rappels 500 ft and does not crater into the ground then a specific amount of energy has to be converted to heat. This does not vary according to rope or descender.

[lostgravity]

I don't think basic Physics allows this to work because as you rappel a certain distance, say 100ft, you will always dissipate the same amount of energy (assuming you don't hit really hard or change weight). What really changes is how the energy (heat) is dissipated.

Exactly, if a 150 lb person rappels 500 ft and does not crater into the ground then a specific amount of energy has to be converted to heat. This does not vary according to rope or descender.

Well, but isn't the question how the heat that gets generated is distributed? Despite the fact that Sterling doesn't make claims about heat resistance, but about durability:

Since there are more carriers in their sheath (or threads, or whatever the correct terminology is), one could think that they could distribute the heat more evenly to more carriers, and each of them gets less hot. But obviously, at the mentioned tests seem to indicate, since there is less material per carrier they tend to absorb the heat not as well as thicker, but fewer carriers in other ropes.

Albeit, that's all just speculation, since I've never been good in physics... ;) It would be interesting to hear a physicist's opinion on the matter of abrasion resistance. But then again, even if it's more abrasion resistant, I wouldn't be too fond of a rope that gets too hot too easily... Maybe we need to conduct some more tests?

Cheers,
David

[cob]

One thing that has yet to be discussed is the relation between type of rope and ascender system. If you use a frog system I would suggest staying away from anything as stretchy as blue water for anything longer than 200'.

I bring this up because I was once stuck at the bottom of Fantastic Pit for 14 of the most miserable hrs of my life, while first 2 (tandem), than 1 caver, tried to climb the 600 ft of BW with frogs. The top one got sick from all the bounce when only 30 ft off the ground. The lower one was only 20 ft off the ground, when I heard their pleas for help. Neither knew how to down climb, and even with the weight of 2 cavers on rope, there was still enuf stretch in the rope that I was able to pull the lower gal down to me without my feet leaving the floor, show her how to do it, then get out of the way. I had to repeat this for the upper gal as well, tho this time my feet actually did leave the floor.

Even if one's stomach can deal with the bounce, a whole lot of your climbing energy is going into that bounce. I have heard from several who do use frogs (I use a ropewalker) that they would never climb more than 200' of BW.

tom

[David_Campen]

Even if one's stomach can deal with the bounce, a whole lot of your climbing energy is going into that bounce. I have heard from several who do use frogs (I use a ropewalker) that they would never climb more than 200' of BW.

I climb with a frog system and Bluewater and I have climbed out of 300 ft free hanging pits on 11.6 mm Bluewater. A 600 ft pit would not be a problem either. Seems that people with very poor frog technique are blaming the rope.

I bring this up because I was once stuck at the bottom of Fantastic Pit for 14 of the most miserable hrs of my life, while first 2 (tandem), than 1 caver, tried to climb the 600 ft of BW with frogs. The top one got sick from all the bounce when only 30 ft off the ground. The lower one was only 20 ft off the ground, when I heard their pleas for help. Neither knew how to down climb,

Definitely sounds like a problem of lack of experience not equipment.

[Scott McCrea]

Exactly, if a 150 lb person rappels 500 ft and does not crater into the ground then a specific amount of energy has to be converted to heat. This does not vary according to rope or descender.

I ain't no expert either. But I don't think it's that simple. How about this...

Say you go down a hill on a bicycle (only coasting, no pedaling) with slick tires in 2 minutes. Put knobby tires on the same bike and it will take longer to get down. If you pedal to go faster so the times are equal, more energy (heat) has been expended with the knobby tires--more friction.

But heck, I don't know. I got a D in high school physics.

[David_Campen]

David_Campen wrote:
Exactly, if a 150 lb person rappels 500 ft and does not crater into the ground then a specific amount of energy has to be converted to heat. This does not vary according to rope or descender.

I ain't no expert either. But I don't think it's that simple. How about this...

Well, since I don't have a degree in Physics I guess that I can't claim to be an expert but I do have a degree in Engineering and got As in college physics so perhaps I can play an expert on TV and, yes, it is that simple.

[cob]

Definitely sounds like a problem of lack of experience not equipment.

Well Dave,

they definitely had no business being on rope of any kind, in a cave of any kind.

As to technique, like I said, I have always used a RW, so my "recommendation" is based on what others who (I hope) know more than I. As to the "bounce=lost energy" equation, it makes sense to me, tho like Scott I didn't do so well in HS Physics.

tom

[David_Campen]

A more interesting physics related question is:

If someone is climbing on a practice rope with a pulley/descender system such that the rope is let out in synchronization with the climber stepping up so that they never gain any height; will the climber expend as much energy as they would climbing when the rope is not being let out?