UKH

Can/should a bachmann hitch be used on double ropes?

Is there any reason to carry mechanical ascenders when using double ropes?

In reply to Osiris:

I've used a normal prusiks to ascend a double stranded rope before (rope jammed on a pull down abseil so had to go back up).

Isn't the Bachmann the one where you use a carabiner as a handle?

In reply to petegunn:

That's correct.

In reply to Osiris:

If you're carrying a guide plate, they work extremely well for the 'body' 'prusik'. I was able to ascend maybe 2x (estimating) as quick as opposed to two prusik knots. Should be similarly good for half ropes. Another interesting prusiking variation taught over here is to attach the foot loop above the body prusik, which in my single test - seemed to be a good idea.
If you're talking only of climbing in the UK, I don't think you'll find anything long enough that speed of ascending the rope is a factor significant enough to carry the extra weight.

In reply to SenzuBean:

Right, I suppose we don't have many big routes here. I wondered if it is even possible in any way to use mechanical ascenders on double ropes or if it must be a single for that application. 

I agree with the guide mode ascent style - with a redirect of the rope above the device onto a prussic/sling placed above it is very easy to ascend.

In reply to Osiris:

Obviously two strands of rope won't fit in most (any?) ascender. You could use them with double ropes - by ascending on a single strand.

I don't personally see a problem with this if the rope diameter is compatible with the device, doesn't run over any sharp edges, etc. Exactly the same precautions as if you were jugging up a single, in other words.

In reply to tehmarks:

Except a Shunt

In reply to scott titt:

I'd argue that a Shunt isn't really an Ascender though...

In reply to tehmarks:

The shunt design is a double rope and safer version of a Heibler? clamp. This was a 60s device , there might be some photos of it in the Eiger Direct book.