UKC

Figure 8 vs ATC belay - which has more breaking power?

I would say ATC but I don't have any evidence to back that up other than personal experience of using both devices. 

It is spelt " braking".

Up to around 9,5-10mm ropes the fig-8 has more braking power than the ATC-XP, the actual ATC is worse.

It depends what you are hitting with them.   I find a figure of 8 much better at breaking bottles than the ATC.

 

Thats interesting and unintuitive. Surely the ATC puts tighter bends into the rope? I've never used a fig 8 as a belay device, only for lowering things.

Agree it's interesting. I do remember a book on rope technique (1970s) by Bill March which recommended, presumably for better braking, using just the smaller hole of an 8 in a similar manner to the slot on a a Sticht plate (no ATCs then of course). That would lead one to think the normal method of use was thought inferior for belaying. Of course there have been many different 8 devices which must each have different properties. I've seen various people using 8s to belay.....IIRC last time at Dancing Ledge where a group of kids was being supervised top roping (I think a second person was belaying the "inactive" rope after the first for safety).

I imagine paying out slack etc is easier with an ATC. Quite often people used to routinely carry an 8 for abseiling but took a tube device for belaying...I asked one and they said they felt abseiling with it was safer.

There's a lot more bending going on though, the first one is particularly effective.

The small hole was used as one would a Sticht plate, it feeds better and doesn't twist the rope if you are inattentive. The other solution to make feeding (and taking in) easier was the so-called " fast-eight" where the rope doesn't go around the spine of the 8 but instead is clipped into the karabiner, I know someone who still uses this with gym ropes.