What is the difference between "dry rope", "non-dry rope" and "dry core rope"?

There are many phrases that you will find concerning dry treatment of ropes, but they can all be easily related to your three categories:

non-dry rope
This rope has no treatment to repel water. Consequently it absorbs the most water and thus getting heavier. Wet ropes also loose some of their dynamic properties, so falls will get harder. As it is the cheapest variant, it is well suited for indoor climbing and also fine for sports climbing (you usually don't sport climb in heavy rain).

dry rope
The sheath of this ropes has a dry treatment. This means that the individual fibres are treated to repel water. As the sheath is on the outside, this is already a good protection against water. This is a goto rope for any multi-pitch, alpine climbing and mountaineering (except in case of heavy icing, see below).

dry core rope
Both the sheath and the core fibres are dry treated. This is an additional protection against water that may pass the protected sheath. As the core has much more fibres than the sheath, this is more expensive. This rope is for ice-climbing and mountaineering in mixed conditions. In those activities it is pretty much possible for a wet rope to freeze which makes it unusable, so it is vital it stays dry.

posted over 9 years ago

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imsodin‭

41 reputation 26 171 6 0

Wet ropes are heavier and provide less energy absorption, which is a big problem when you can't avoid wet conditions and you rely on your rope to protect you if you take a fall.

Dry ropes have been impregnated with a fluoropolymer-based solution to prevent them from absorbing as much water as possible. Use of dry ropes is essential for alpine and ice climbers, or for glacier travel. Non-dry ropes will suffice in other conditions, although a dry treatment is also useful for reducing wear from abrasion, and it provides better energy absorption.

There are at least two types of dry ropes, those that have a single dry coating, and those that are "double-dry", they've had both their sheath and their cores coated. Single dry ropes typically are only coated on their sheaths, but the coating tends to wear off quickly, so some manufacturers use a single treatment that penetrates to the core.

The terminology doesn't seem to be consistent, some distributers only categorize ropes as dry or non-dry, others add categories like dry-core, dry core and sheath, or 2X dry. But the difference is just how many times the ropes are treated to be water resistant.

^{1 MEC - Choosing a climbing rope
Image: Outdoor Blueprint - Climbing Ropes}

posted over 9 years ago

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ShemSeger‭

1774 reputation 82 481 195 0

This question has already been well answered but I would like to address a slightly different point:

What's the problem with a wet rope anyway?

Dynamic climbing ropes are, to the best of my knowledge, universally manufactured from Nylon 6 or Nylon 6,6. Nylon is a somewhat unusual polymer in that it readily absorbs water, and its properties change significantly when it does. The material is hydrophilic enough that even atmospheric humidity causes significant water absorption. The issue is not simply water between the fibers of the rope, making it heavy, or stiff when frozen, but a fundamental change in the material of the rope itself. The glass transition point drops considerably, causing tensile strength to fall and creep to rise. A wet nylon rope is weaker and less able to recover from stretching in just the same way it would be if heated excessively.

In applications involving water nylon should be avoided when possible and that is exactly what one sees in caving and canyoneering ropes: the use of polyester, which is not significantly affected in this manner. Unfortunately polyester does not have the elongation and energy absorption needed for a dynamic climbing rope so rope manufacturers are left trying to patch an inherent problem, and that patch is hydrophobic treatment as described in the other answers.

posted almost 9 years ago

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Mr.Wizard‭

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What are the differences?

The different ropes basically differ by how they have been treated to handle water: non-dry ropes (although I've never seen that mentioned explicitly) have no special treatment at all, dry ropes have only the sheath, treated with some water-repellant, while dry core ones also have a treatment for the core. In both latter cases, the dry coating does not make the nylon fibres immune to water, it just prevents that they suck up any water immediately.

Why does it matter?

A rope can soak up a significant amount of water that will make it heavier, worsen handling and will strongly reduce the dynamic strength, i.e. the fall energy it can absorb – the figure of 70% loss in strength is around. Besides that it does also not matter much whether it is soaking wet or just damp, as stated here

Tests have shown that just being splashed under a shower had comparable strength reduction to ropes that have been fully soaked; i.e., the amount of strength and performance loss is nearly equal for both a damp rope and a fully soaked rope.

So basically everything more than some single rain drops may be too much. But it should also be mentioned that these issues are temporary, so once you have dried the rope it does behave as before. The only exception is the case, where the rope has taken a lead fall while wet, in that case it may have been significantly weakened and it is better to discharge it:

Any fall on a wet rope causes more damage, so its future performance (even when dried) is compromised. (source)

Which treatment for which use case?

Concerning the question which rope to use for which activity: I would say for 90% of climbing activities you are fine with a non-dry one and a rope with dry treatment is just wasted money since the treatment will wear down as you se the rope.

So as long as you use your rope for activities where you don't expect to have it exposed to water or snow for prolonged times, a non-dry rope is enough. This covers basically indoor and outdoor sports climbing since normally you are only performing those activities in fairly good weather and even if some unexpected rain shows up it's no problem to rappel down one pitch on a rope that got a bit wet from the rain.

For multi-pitch rock climbing, it is somewhat debatable if a dry coated one is just nice to have or essential. It depends a bit on what type of climbing you are doing there. If you are just doing some multi-pitches in a developed climbing area where you just rappel down some pitches, get to your car and rush home if it starts to rain, you won't need a dry rope. You can do all this also on a wet rope – the handling will be a bit uncomfortable but it works. If you are climbing in some alpine area where there is a chance that you have to rappel some ten pitches in a heavy rain storm on a soaking wet rope with cold water running down the rope as the rappel device squeezes it out of the rope and the whole rappel taking twice as long since friction has increased dramatically and then you have to hike out another one or two hours while carrying your soaking wet rope that is more than twice as heavy as in dry condition, you will condemn yourself that you wanted to safe those bucks on a dry coating. If you plan to climb on the last few pitches to the top instead, you should make sure you have a rope with dry coating, since a not coated one might break under a lead fall (source).

Where a dry coating is quite inevitable is everything where it is clear a priori that the rope will come in contact with water and/or snow, i.e. ice climbing and glacier hiking.

In short

Rappelling on a wet rope is ugly but still OK – having a lead fall into a wet or even damp rope may be critical. So whenever there's a chance that you will have to climb on (and not just rappel down to go home) even after your rope has been in contact with water, you should invest the additional money for a dry coating. On the other hand, it's wasted money for the most widespread cases (sports climbing) where you just stop as it starts to rain.

posted over 9 years ago

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Benedikt Bauer‭

181 reputation 4 67 21 0

Dry ropes and dry-core ropes are very similar. Basically they've been treated so they repel water (this does not make them water proof). "Wet" ropes have no treatment.

What do these terms mean, and what are the conditions or types of climbing in which you would prefer one or the other?

If you live anywhere where it rains and you plan to climb (dynamic loads), I'd get a dry treated rope. Almost everyone in the UK has some kind of dry treatment on their ropes.

So why do this?

Basically a wet rope is not a good thing.

Rope companies do not recommend falling on a wet rope, which may have its dynamic performance reduced by up to 70 percent when wet. Modern dry-treated ropes are a bit better, with dynamic performance reductions of about 40 percent, depending on the type of dry treatment. Any fall on a wet rope causes more damage, so its future performance (even when dried) is compromised.

So how wet does a rope need to get for it to be compromised?

Tests have shown that just being splashed under a shower had comparable strength reduction to ropes that have been fully soaked; i.e., the amount of strength and performance loss is nearly equal for both a damp rope and a fully soaked rope.

This is where the dry treatment comes in. A dry treated rope will likely pass the "shower test" where a wet rope won't. But if you submerge either into a pool for any length of time and they could be compromised.

So I shouldn't get my rope wet?

No, getting it wet isn't a problem, getting it wet and then using it is. It's actually a very good idea to clean your rope once in a while.

If there were any long-term effects of soaking and then drying ropes, rope manufacturers would not recommend washing them at all. However, the rope has more elongation and is more susceptible to abrasion when wet, which can reduce the cord's ability to absorb future impacts

Sources

TL;DR

The important thing to remember is that a wet rope is a compromised rope. Dry treatment will help prevent it getting wet but if it get's wet, don't use it for anything dynamic.

If you do fall on a wet rope then you should retire it immediately:

So if it underwent any major trauma when wet, retiring the rope is recommended.

A note on gorge scrambling.

It's common (in the UK at least) to use ropes while gorge scrambling. This is fine as they are typically confidence ropes and will be under static load (as opposed to dynamic falling loads)

posted over 9 years ago

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System‭

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