Rope Choice

[ratagonia]

Tom did a water absorption test last year showing that a dynamic climbing rope absorbed over 20% more water than a polyester canyon rope.

Singing rock has an article showing even more water absorption, up to 59% of the original rope weight.
http://www.singingrock.com/article.a...&nLanguageID=2

Elongation on most canyon ropes is 1% - 2%, not 3.8%, making the 7.2% a much bigger difference. Also nylon gets significantly more stretchy when wet, I don't have stats on that just personal experience.

"Static Ropes" is a general class, and elongation will vary substantially between brands and models. I just checked the test data, and Imlay ropes (Polyester/Polyester) stretch between 1% and 2% at 400 lbs, or likely between 1/2% and 1% at 200 lbs.

I think it makes a big difference, and prefer ropes that are very static, especially when rappelling in water or when the rope is wet. But then again, I have gotten very used to using truly static ropes.

Tom

[ratagonia]

I think that most of the water weight is water that clings to the rope due to surface tension rather than actually being from the saturation of the material. Dynamic climbing ropes tend to be made loose, giving them lots of space inside to keep water. Canyon ropes and some other static ropes tend to have a tighter weave that doesn't leave much space for water.

Most of my ropes are nylon: 9mm PMI max-wear. It is very hard and stiff and I've never even noticed any weight difference when wet. My older 11mm Bluewater static (now retired) did gain enough weight to notice.

Yes. There is absorption (internal) and adsorption (external). Nylon does both, as the nylon molecule hydrates by forming weak bonds with some water molecules; thus some absorption takes place, which also changed the physical properties of nylon (=weaker, less tough, longer, self-lubricating). Polyester and nylon both adsorb water, but the details depend on a lot of variables. There is no reason to think that these two different chemicals would have the same effective surface tension and therefore the same amount of water clinging to their exterior.

The weave of the rope might also make a difference in both of these. I can see a tightly woven rope resisting penetration of the water for an hour, whereas a loosely woven rope might not.

Please notice in the testing protocol that after soaking for an hour, the ropes were hung up to drip for 10 minutes before being weighed.

Bluewater makes quite a few different models of static rope; some are tightly woven and some are not. PMI makes several different models, the max-wear being very, VERY tightly woven. An unusual rope.

Tom

[ratagonia]

Its kinda funny, though, that the only folks who complain about dynamic climbing ropes being stretchy or bouncy on rappels are canyoneers. Climbers just don't give it much of a thought. Its pretty rare to see a thread on any climbing forum about climbing ropes being "bouncy" on rappel (not sure I can recall one).

You mean, people who have only ever rappelled on dynamic climbing ropes have little to no awareness that actual static ropes have significantly different properties?

Tom

[ratagonia]

As far as nylon getting more stretchy when wet? Not sure about that.

Sterling says: “Another problem with wet ropes is that when core filaments become wet they lose their strength in addition to losing their dynamic elongation properties.”

Singing Rock: “After soaking in water a rope becomes 4-5% longer, which can be correlated to the 5-10% increase of the impact force at the first fall on the Dodero machine.” "It has also been noted that the impact force at the first fall with the wet rope is significantly larger (5-10%), as if the rope had become more rigid than the dry one. This could be due to increased fibre-fibre friction as well as to the increased length of the rope. A rope that is already stretched is indeed more resistant to strain, more "rigid". The stretching - average 3-5% - measured on wet ropes just after removal from water is not negligible compared to the strain that occurs in the Dodero test (30-35%)."

To me, that implies that a wet nylon climbing rope actually increases in length, and, loses its stretch, which is why the impact force is so much higher. Dunno for sure, though. Hank?

Uh, let's not lose track of an important parameter here. A dynamic climbing rope is not just a rope made of nylon. After being made, it is (usually) electrostatically treated to achieve the desired dynamic properties. My (feeble) understanding is that the treatment causes the nylon molecules to crinkle, and the overall length of the rope decreases. The addition of weakly bonded water molecules may un-crinkle some of the crinks (that's a technical term) so the rope loses dynamic properties and gets a little longer.

Also, wetness tends to increase sheath slippage, either by making the sheath bigger or by lubricating the interface. When we rappel, we rappel on the sheath - the core is just there to keep the sheath spread out. Many of the problems I have seen rappelling on wet rope is due to the sheath slippage, rather than to other factors.

Tom

[Brian in SLC]

You mean, people who have only ever rappelled on dynamic climbing ropes have little to no awareness that actual static ropes have significantly different properties?

Nope. I give climbers more credit than that.

Static ropes, as a catagory, are significantly different unto themselves.

Dynamic ropes, for me, and, as a general rule, seem to have better "hand" and are more pleasant for me to rappel on. Can't recall when I've had as rough a rope as a canyon specific static line which felt like it was going to take a chunk out of my hand. Canyon Pro DS for one. Some are quire "bitey". Geez, I can almost see why folks use gloves to rappel with (ha ha!). If a canyon rope is thin and light, they tend to be fast (old BW Canyon Pro's seemed quite slick).

Might be a mindset difference too. Dynamic climbing ropes are used for going both up, and, down. For canyoning, most all of the rope use is for rappelling. So, holding a fall, carefully paying out rope to a lead climber, swapping leads, etc, all slightly different when it comes to time spent with a rope. Could account for some of the differences in "feel" folks have about their ropes.

Kind of an environment thing, too, I'd guess. Canyons and especially slots in Utah have a specific geometry to them that you descend, which, is sometimes different than your average sport climbing cliff, or, even a more traditional area with long time located standard belay/rappel perches. Maybe as the sport matures, this will change a bit over time? Anyhoo, seems like a lot of the canyon rappels down watercourses always have a bit of funky geometry to them which can tend to eat ropes over time. Ditto climbing in the Utah desert too, which, can also be hard on ropes.

Hey, looking on Sterling's site, I see a rap device called the F4. Anyone seen/used that rig? Interesting...

[dougr]

Thanks for the advice all. We will see how it goes. My next investment will be an 8.3mm Canyon Fire. Its what I learned on.

Spring for a technora sheathed rope if you can. Monster toughness. Sterling C-IV for 0.87/ft here. This is an unbeatable price for the single best rope for canyoneering IMO. Great hand, tough sheath, 3.2 lbs/100' light, hydrophobic, and as cheap as the low cost polyester ropes available elsewhere.

[hank moon]

Spring for a technora sheathed rope if you can. Monster toughness. Sterling C-IV for 0.87/ft here. This is an unbeatable price for the single best rope for canyoneering IMO. Great hand, tough sheath, 3.2 lbs/100' light, hydrophobic, and as cheap as the low cost polyester ropes available elsewhere.

Hmmm. I'm a bit leery of polypropylene for rope core. Wet canyons only?

[dougr]

I understand the polypro core hesitance and cannot fault eschewing such. I have technora sheath, nylon core ropes as well. But in practice, canyon ropes die their early deaths from the wear on the sheaths. Cores are secondary imo and I go nothing but full technora now. Polypro for wet and nylon for dry is an admirable compromise if you want sets of rope. The soft core yields such a great hand.

edit: I was thinking about your leeriness more Hank. I was the same way before I bought the C-IV. In fact I didn't buy the C-IV for a while, getting the technora/nylon variants from BW and Sterling. With an MBS of only 4650, vs. 5k or even 6700 in the case of the 9mm BW CanyonLine I use, I thought I was giving up too much margin. But when you consider the 1" nylon webbing we all use and love, me included, is MBS 4k when dry, then reduced by a ring bend, then reduced when wet, and in the case of a technora/nylon having some reduction when wet, well, it all seems plenty strong. I trust my gear more now. I have faith in my knots, faith in my anchor setting, and faith in reducing sheath wear using techniques, all the while having the toughest sheath possible. Good combo that makes a paltry 4650 MBS OK in my book. Plus it's knottability is the bomb. A shame it's not more popular. I hope it's not discontinued.

edit2: Story. In a canyon some time ago I passed a group of two going slow. I went down their amazing rope. Just so silky. The guy was a well equipped vet of mostly dry canyons. I asked what it was, C-IV it turned out, and was interested after that. For those who haven't used it, it's remarkable. I don't know what else to say. Kind of like a dynamic or a valdy in feel. Very much unlike the typical feel of a tight weave poly. After finally getting one, easily my favorite. I expect wear to be outstanding as have all my technora ropes been. Never had a dual sheath, so can't comment on how much better than that.

Man I sound like a paid Sterling shill.

[ratagonia]

I understand the polypro core hesitance and cannot fault eschewing such. I have technora sheath, nylon core ropes as well. But in practice, canyon ropes die their early deaths from the wear on the sheaths. Cores are secondary imo and I go nothing but full technora now. Polypro for wet and nylon for dry is an admirable compromise if you want sets of rope. The soft core yields such a great hand.

edit: I was thinking about your leeriness more Hank. I was the same way before I bought the C-IV. In fact I didn't buy the C-IV for a while, getting the technora/nylon variants from BW and Sterling. With an MBS of only 4650, vs. 5k or even 6700 in the case of the 9mm BW CanyonLine I use, I thought I was giving up too much margin. But when you consider the 1" nylon webbing we all use and love, me included, is MBS 4k when dry, then reduced by a ring bend, then reduced when wet, and in the case of a technora/nylon having some reduction when wet, well, it all seems plenty strong. I trust my gear more now. I have faith in my knots, faith in my anchor setting, and faith in reducing sheath wear using techniques, all the while having the toughest sheath possible. Good combo that makes a paltry 4650 MBS OK in my book. Plus it's knottability is the bomb. A shame it's not more popular. I hope it's not discontinued.

I think you're barking up the wrong tree there dsr70. The issue is not the lowish breaking strength, the issue is the low melting temperature of polypro, or, more technically, the low transition temperature of polypro, transition temp being the temp at which it starts to melt and the strength goes down dramatically.

I think the key here, Hank, is the Technora sheath, which provides both physical and temporal... hmmm, temperaturish protection to the core of the rope. It would not be my first choice for the final rap in Heaps, but the CIV has been around a while, Sterling is a legit company, and I have a trust that it works for general canyoneering.

I used one last summer, and it was good. The surprise was that it rappels pretty much like an 8mm rope, rather than a 9mm. So, first time out, be sure to set it up with enough friction.


Tom

[jwurst]

You cave on dynamic?

No, certainly not. With even the most static of ropes, if you have several hundreds of feet above you then you have a fair amount of stretch.

[hank moon]

I think the key here, Hank, is the Technora sheath, which provides both physical and temporal... hmmm, temperaturish protection to the core of the rope. It would not be my first choice for the final rap in Heaps, but the CIV has been around a while, Sterling is a legit company, and I have a trust that it works for general canyoneering.

Yeah, I should have mentioned earlier that lower melting temp (and critical temp) of polypro was the concern...

Ditto last rap in Heaps. Perhaps I'm overly cautious/paranoid about polypro - would love to see/do some testing. I know some of the earlier Euro polypro ropes were specified to be used only when wet. They didn't have Technora sheaths, though...

[hank moon]

No, certainly not. With even the most static of ropes, if you have several hundreds of feet above you then you have a fair amount of stretch.

yah, Ellison's and Golondrinas come to mind as super-stretch pits

[dougr]

I'm going straight to the horse's mouth. Text of email to Sterling:

-------------------
Matt,

I have bought several Sterling ropes over the past few years, and most recently a C-IV for canyoneering. Great products you have.

The C-IV is my first polypropylene core rope. I want to know if the low melting point of the core might be of concern on certain rappels. A few questions that come to mind:

1. Do long and/or fast and/or heavy person rappels generate enough heat to penetrate a sheath and raise core temps to any appreciable degree?
2. Does the technora sheath of the C-IV specifically offer more insulation than a polyester or nylon sheath?
3. Are there any restrictions on use placed on the C-IV owing to the core?
4a. More technical, in a worst case scenario (hot day, heavy person, dry rope, fast and long rappel, rappel device that imparts maximum heat), what is a core temperature raised to in say a C-IV?
4b. More technical, what is the melting point of the C-IV's core?

Thanks for your time. I saw no technical contact link on the website, and you seemed the best source.

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

Will post their reply.

[Bo_Beck]

Maybe not too pertinent to the thread but certainly felt I would mention: According to Kirk Mauthner (past owner of Rigging for Rescue), there are 3 classifications of ropes. Static, Low Stretch and High Stretch "Dynamic". A static rope would be classified as one that has less than 5% elongation. Low stretch ropes fit in at 5% but less than 10% elongation, and high stretch "Dynamic" ropes are classified as greater than 10% elongation. Having rappeled on various types and manufactures of rope certainly has shown me varying differences. Most rope companies classify their rescue ropes as "Static" but I can honestly say that some of their claims seem to fit better into the "Low Stretch" category. In Zion NP we have sort of chosen the NE 7/16 KMIII rope for the last several years which has 5.1% Elongation at 2.7KN. At the critical zone (edge transition) 2.1% at 1KN. Several years ago I rappeled from the top of Angels Landing (South Face) to the ledge below. The distance was somewhere around 900', using a KMIII. I'm not quite 1KN but with gear I was close. When I arrived at the ledge I had to feed 15' or so of rope to detension. If I'd been using a high stretch rope it would have been 90' or so to detension. BIG DIFFERENCE! Same applies to jugging the Great Arch which I've done several times. It takes a while to get airborne! The Great Arch rappel/jug is about 450' I'd hate to jug the arch on a high stretch "dynamic" rope! It'd take forever to get your feet off the ground!

[dougr]

Great stories Bo.

Sent from my ICS'd Vibrant

[spinesnaper]

I think you're barking up the wrong tree there dsr70. The issue is not the lowish breaking strength, the issue is the low melting temperature of polypro, or, more technically, the low transition temperature of polypro, transition temp being the temp at which it starts to melt and the strength goes down dramatically.

I think the key here, Hank, is the Technora sheath, which provides both physical and temporal... hmmm, temperaturish protection to the core of the rope. It would not be my first choice for the final rap in Heaps, but the CIV has been around a while, Sterling is a legit company, and I have a trust that it works for general canyoneering.

I used one last summer, and it was good. The surprise was that it rappels pretty much like an 8mm rope, rather than a 9mm. So, first time out, be sure to set it up with enough friction.


Tom

Tom

That's interesting because I purchased a 300 ft length of C IV precisely for that application. C IV is an expensive sheath of technora with a light filler core. The rope is significantly lighter than 8.3 mm Canyon Fire at a higher price of course. At 300 feet, the C IV is 3 pounds lighter than the Canyon Fire of comparable length. There are some thermal studies out there for this rope. The technora is profoundly heat resistant and as I recall the sheath protects the fragile polypro core. Having said that, there is no question that the fire canyon will most likely out last the C IV and of course the value is unquestioned. My 60 m canyon rope is a Canyon Fire.

Ken

[dougr]

Ken, why do you think the Fire will outlast the C-IV? Sheath is always my problem long term, and I don't see technora being bested. My 3 are beasts compared to the many poly sheaths I've had. What am I missing? My working lengths and 60m are technora, poly are backups now. What, is the Fire's weave so tight it bests a "normal" technora weave?

Doug

[spinesnaper]

Doug

Good question. First there are a lot of people out there who love their sterling canyoneering ropes. What I am saying is that I foresee my 60 m Canyon Fire rope lasting longer at that length than the 300 ft CIV rope lasting as a working 300 ft rope. I just think that paranoia will cause me to retire this rope from this length much sooner than my 60 m rope. Although the technora is very tough, I suspect that psychologically I will be pretty intolerant of even minor sheath damage. I also suspect (and I could be wrong) longer raps are going to be tougher on ropes than shorter raps in terms of sheath abrasion. I would be interested in any insight on this issue. Of course they also say that you can destroy your brand new rope the very first time you use it in the field.

Ken

[Branin]

I was rather unimpressed with my Fire actually. It wore out FAST. Could have just been one of those weeks though... I plan to give the fire another shot someday, in the name of scientific rigor.

(No offense to you Tom, the rope just wore out quickly).

Most of my work-horse ropes are Blue Water, of one type or another. I also have an Edleweiss nylon static line that I really like... As long as the canyon is dry.

[Brian in SLC]

I have the Sterling Canyontech. Would love to wear that thing out. My bet is, I'll probably wear out before that rope does...ha ha.

Burly cord. I've only got a few canyons on mine, but, it still looks new.