Extremeophile wrote:There are certainly many examples in vertical work of relying on a single point of attachment or single piece of gear (after all, it is called SRT, not DRT). I've heard some talk about rope maneuvers that rely, if only briefly, on one ascender. The difference is that descenders, locking crabs, ropes, trees, some natural anchors, etc are "bombproof". Ascenders have been known to twist off ropes and are only rated to around 4kN. I sometimes trust a single point of attachment, but I don't think I'll adopt trusting a single point if it's an ascender.
Hmmm. I understand the functional differences, but I don't consider the ascender versus everything else issue quite so black and white. I'm curious - do you know of documented examples where modern toothed-cam ascenders (e.g. Petzl) have twisted off a rope in normal SRT use in a frog system? It is my understanding the 4kN MBS is a reflection of the expected failure mode when overloaded - i.e. stripping the sheath off the rope, not having the device itself fail. Hence they are more appropriate for ascending, work positioning and fall prevention rather than true fall protection/arrest.
I am not necessarily advocating the use of single point ascender attachments during changeovers. To each his own, depending on the circumstances. You spend a lot of time on rope, and I'm sure you have an appropriate routine figured out that works for you.