Keeping Your Climbing Rope Hydrophobic
If you’ve lugged a sodden rope out of the mountains, or belayed with a frozen rope, then you’ll understand the importance of dry treating ropes. The irony is, dry treating ropes is also important for durability and handling in dry conditions. The real question of dry treatment isn’t one of importance, but rather, is the treatment worth the additional cost.
Ropes are made from hydrophilic – water absorbing – filaments of Nylon. If a rope becomes wet it will be heavy and could freeze into a steel cable-like cord. Another problem with wet ropes is that when core filaments become wet they lose their strength in addition to losing their dynamic elongation properties. Tests by Sterling found that wet ropes may be 70-percent weaker than dry ropes. Although strength and elongation return after the rope dries, having the rope function properly while wet arguably makes dry treatment essential.
Dry treating ropes adds a hydrophobic – water repelling – coating to the filaments of a rope. There are two basic types of dry treatment. The first is sheath treatment, which is better for dry conditions such as cragging, sport climbing or gym climbing. The second type is sheath and core treatment, which is ideal for mountaineering, alpine climbing and ice climbing.
Sheath treatment helps keep water from entering the rope’s core and makes the rope more slippery in dry conditions. A slippery rope is easier to handle and has less friction (drag) that abrades the rope that can make it fuzz-out more quickly. Sheath treating also tightens the sheath, helping to keep out abrasive, silica-based dirt that weakens the rope’s core. Many manufacturers now give all their dynamic ropes a sheath treatment, like Beal does with their standard Dry Cover treatment and Sterling does with their Arid system.
Sheath and core treatment coats the individual filaments of the core to repel water and reduce yarn-on-yarn core abrasion. Another benefit of having the core treated, in addition to the sheath, is to prevent the core from soaking up water if the sheath leaks. Most dry core treatments are done before the braiding process by coating the individual yarns then curing the coating, which creates a chemical bond between the coating and the yarn to improve durability. Examples of sheath and core dry treatments include Sterling’s DryCore, Beal’s Golden Dry, Blue Water's Double-Dry, Petzl’s Duratec Dry, and Maxim Ropes' 2x Endura Dry.
The major problem with dry treatment, in addition to cost, is the treatment wears off, especially sheath treatments. While it isn't an exact science to why the treatment wears off quickly for some and slower for others, don’t be surprised when your expensive dry rope becomes a sodden lump or a frozen cable after one season of use. The limited durability of sheath treatment makes core treatment that much more important – if the sheath leaks then your core will maintain some dryness. If your dry treatment does wear off, then you can reapply the dry treatment with Sterling’s Pro Arid dry treatment or Nikwax’s Rope Proof.
So, should you drop 20 to 50 extra dollars for dry treatment? The short answer is yes. Ropes are arguably the most important piece of climbing equipment. Forgo the expensive freeze-dried meals and eat Ramen, just don’t skip dry treatment, no matter how expensive it might originally seem.