Ropes

As guides and instructors we are constantly on the look out for ways of reducing our load while maintaining adequate margins of safety for our clients and ourselves. Almost nowhere is the balancing act more evident than in our choice of ropes.

We have all looked at the new skinny ropes and wondered just how skinny can they get? Well the jury is still out on the durability and life expectancy. But if you are smitten and looking for the smallest lightest package remember weight per metre is a better gauge of rope size than rope diameter after all can we really tell the difference between 9.4 and 9.7 mm.

Glacier Travel
The UIAA has recently accepted the single twin rope as satisfactory for glacier travel. Initially this sounds like great news and some of us are already feeling the reduced stain on or backs. However like all equipment decisions the choice may not be quite so simple. Is it ever? Just to add fuel to the fire, the UIAA does not control the manufacturing standards for ropes and currently we can find no manufacturer who approves of their twin ropes to being used singly.

Some further considerations:

• Is the rope sitting in the pack while you travel the glacier to be used only in the case of an unexpected emergency? In this case the single twin may be a good choice and although heavier than 5.5 Spectra cord it is far more functional, durable and much easier to handle.
  
• Is this a more hazardous glacier where the rope will be worn while travelling? A slightly thicker rope, such as a ½ rope, may be more appropriate. It will be more durable, less likely to be terminally cut by crampons or skis and easier to manage in the case of a rescue. Generally fatter ropes will stretch less under body weight an important consideration when rappelling, ascending and raising.
  
• Is the glacier just part of an approach to a more technical route? Although ropes rarely break under load alone they do break when cut/abraded over an edge. When climbing on routes where the forces may be higher and the chance of the rope being cut over an edge greater, consider using a designated single rope.
  
• Speaking of cutting the great advantage of the twin rope system is its resistance to ultimate failure. It is highly unlikely that both ropes will be cut over an edge. When climbing shorter pitches doubling a single twin for the technical sections and using it single while crossing a tame glacier may be a reasonable choice. Just keep in mind the increased rope handing problems incurred using twin ropes.

Climbing
Our choices when climbing technical terrain have also increased with the growing number of skinny single ropes and the expanded role of ½ ropes. Like glacier travel the nature of the forces and the type of abrasion that the rope are subjected to varies and therefore our choices. Manufactures are understandably cautious when it comes to recommending how their ropes should be used when it comes to ½ and twin ropes.
Some further considerations:

• When choosing a single rope consider its primary application.
  • Is it going to be used for instruction in which case the fatter, 10.5-11 mm ropes, last considerable longer than their skinnier brethren.
  • Will the rope be used in alpine rock terrain where it could be subjected to rock fall, edges or used for lowering etc. Again fatter ropes are more durable and have a greater safety margin.
  • It is interesting to note that not all rope manufactures have jumped on the supper skinny single rope bandwagon. Some manufactures question whether these ropes really meet the single rope criteria. Just because something meets certain defined criteria does not mean it is safe in practice.
  • Alpine ice routes and hard red points may be the perfect applications for the 9.4-10 mm ropes
• So what about leading on two ½ ropes?
  • When climbing with one other person the ½ rope combo is great for wandering routes were each rope can be managed separately to reduce rope drag.
  • This set-up is functional on waterfalls where rapping is the preferred descent method since you can rap a full rope length.
• So what about leading on two ½ ropes and then belaying two clients on individual ½ ropes?
  • Recently manufactures have suggested that in certain situations this may be acceptable. The emphasis here is certain situations. Note: Some manufactures recommend against this practice.
    • One of the most common applications is waterfall guiding where there is little chance of the rope(s) coming in contact with sharp edges.
    • Slab routes also minimize the chance of serious abrasion and second falls generate minimal force.
  • On the other hand belaying a second on a half rope may not be a wise choice on rock routes where the rope could lie over sharp edges or pendulum falls could occur which greatly increase impact force and rope abrasion.
  • Consider to the extra stretch under body weight and low forces experienced with ½ ropes. This could cause problems if a client falls on a difficult move just off the deck or ledge and craters because of stretch. Rappelling raising and ascending are more difficult on ½ ropes.
• So does the twin have a place in the guides quiver?
  • Twin ropes are designed to be used in pairs. They have great resistance to being cut over edges (when paired) and are a lighter alternative to ½ ropes when you don’t need the advantage of placing the ropes in separate pieces of pro but do need the extra length for descending.
  • So what about belaying a client on a single twin rope. Consider this very carefully. We can find no evidence of this being recommended by a manufacture and twin ropes have never been design for this purpose. This is a very skinny piece of cord to hang someone’s life on. There is always potential for higher forces than expected in a second fall. We build in safety margins in to all we do, is the weight saving worth taking a piece of equipment so close to its tolerances. Let your conscience be the guide, there are certainly situations in which forces and abrasion can be controlled and a single twin may be up to the task, just don’t become seduced buy the weight figures.

Keep in mind in whatever rope choice you make, if there is an accident you will have to defend your choice and it is much more difficult to explain practices that are not well recognized by the industry, standard setting bodies, or the experts.