So, I've decided to go with a method that someone on here talked about (sorry forgot username) when on glaciers with only 2 people. One A ties into the middle of the rope, then the 2 strands go to the person B. One of those strands has butterfly knots in it but the other strand doesn't. Person B then ties into both strands with ~15-20 meters between persons. Person B then takes coils with the remaining rope.
In the event of a fall, the strand WITH butterfly knots is slightly shorter than the strand without, therefore in a fall the strand with the butterfly knots takes the load and digs into the lip. The other strand is slightly slack. This slack strand without knots can then be used to haul the fallen climber out.
One problem with this is if person B falls in, then person A has no coils with which to create a haul system. My idea is that they have in their rucksack a length of static rope that they can use to create a Z pulley or a Z+C system.
I've attached a link to a drawing I've done...I'd be really grateful if someone could critique it please
https://flic.kr/p/vpjdEV
Potential problems:
-On traditional system only P1 must be bomb proof...in this system P1, P2 and p4 must be bomb proof since the red rope between p1 and p2 will go slack.
-More gear and so weight
-More to potentially go wrong/ make mistakes.
Thanks for any help, I think this system will work but could do with another eye. Cheers
Post edited at 13:43