Rigging the Alpine Up Belay Device to Reliably Auto Lock with Single Rated Ropes

Consistent with what others on have posted on this site (see here and here), I have found that when using the Alpine Up with two 8.5 mm half rated ropes with a simulated leader fall, the device caught and locked every time without my hand touching the brake strands (at least in the tests I have done).  Conducting the same test with a single strand rope (tested both 9.5mm and 10.2mm diameter ropes) indicated that the device generally would not catch without a hand at least lightly on the brake strand.  Whether or not the device locks with no brake hand input, using a single-rated (fatter) rope, seems to depend on where the pile of rope feeding the device is located relative to the device.  If the pile of rope is down and behind the belay device, then the Alpine Up would generally auto catch with no hand on the brake strand.  However, if the pile of rope was directly below or in front of the belay device (more typical), then the device did not auto-catch with a single strand simulated leader fall unless a hand was at least loosely holding the brake strand.

However, I did find a simple way to re-rig how the single strand rope was fed to the device that caused the device to catch every time when tested with 9.5mm and 10.2mm ropes with no hand on the brake strand (the incapacitated belayer situation).  The re-rig is to simply clip a carabiner to the front most harness gear loop on the side of the brake hand, and then just redirect the brake strand through it as shown in the picture below.

In this configuration, you place your brake hand on the loop of rope between the Alpine Up and the redirect carabiner.  I have used this setup in actual outdoor climbing settings and found it really doesn't complicate belaying much at all.  It is a minor annoyance to have to pull rope through the carabiner as you feed out slack to the leader, but you get used to it pretty quickly.  I bought the Alpine Up primarily for use with half ropes, but I also like to use the setup shown above as an added layer of safety when I have my teenage son belay me when we go climbing together.  Hopefully others will find it useful as well.

I have done the same but with a legloop redirect, I was afraid of stepping on the rope and tearing the gear loop off. 

Interesting.  I can see how that would make the device more reliable.  Personally I just keep a hand on the brake line.

Why take your hand off the brake side?

I don't... I didn't notice that as a reason to practice this in his post till you mentioned it... I use it ice climbing and wet rope slips easily through both it and my hand.