I was cleaning a route the other day and how the rope ran through the chains was twisting my rope up right after the knot. There was probably a good 2 feet of rope all twisted up into a big clump. Does this make the rope weaker if I were to take a fall with some slack in the rope? I assume it does but not enough to worry about but I'd like to hear what other people know. Thanks
i have a friend (very experienced climber) who was TR'ing a route and the kink in the rope unclipped the rope from one of the anchor draws. i have also personally arrived at the anchor (several times) with a kink that was positioned to where it could potentially open the gate. for this reason i (my friend also) always set it up with at least one locker (often 2 lockers) if somebody is going to TR the route. i always recommend this to others as well, although they often kind of scoff at it.
the main cause of this usually seems to be if the TR isn't pretty much directly vertical at the anchor - if one of the ropes is coming in at an angle, due to a traverse, it tends to introduce a twist in the rope.
I have never heard of an accident but I think a twisted rope as it comes into the belayer's device while belaying a leader could kind of pop out of the belayers hand or at least cause them to remove the brake hand to untwist the rope. The same danger might happen on rappel if the rope is twisting below the device as you descend.
Even if you took a hard lead fall on a kinked rope, I doubt a person would be capable of generating enough force on a good rope for a kink to make any signficant difference in strength. It seems more likely that falling on severe kinking could promote hard or soft areas in the rope, and that affects the lifetime of the rope. Unless my car takes a lead fall, ropes almost always break because they get cut on rock or burned with friction (such as nylon-on-nylon).
Slim: Good call on kinks opening gates. That is a valid concern.
...always set it up with at least one locker (often 2 lockers) if somebody is going to TR the route. i always recommend this to others as well, although they often kind of scoff at it.
It's one of those official rules of climbing that most of us probably don't follow but should. Many accidents could probably be avoided by following these kinds of rules. However, it might also have something to do with choice of TR route, belay technique, and rope management. I've never experienced extreme twists (and have never at the anchor) except when I don't flake out the rope very well --- or at least, that's what I always attribute the twists I see to. Sometimes whatever twist is there can be 'compressed' (from along the whole rope, to a short section) by climbing on it.