Dow Williams wrote: Don't know if it is an English translation problem regarding what was written above or what....but none of us will use both the double rope and twin rope technique in the same pitch of climbing. I consider this quite unsafe when analyzing what forces could be in effect during a fall.
the old mammut manual said it could be used as doubles and twins in a single pitch ... ive asked mammut a few times and each time the response has been the same ... keep in mind they are a reputable company and these exchanges are a matter of record through email
id personally take mammuts word on it
there was some discussion as to how much extra force using doubles as twins ...beal indicates that an 8kn double used as twins generates ~13 kn (for 80 kg i assume) ... when you consider that the single/twin rope limit is <12 kn ... and that even a beefy mammut genesis is rated at 6kn (at 55 kg) ... its no surprise IMO that mammut says its perfectly fine to use any mammut half rope as twins keeping the forces in mind, and that they are tested as such
i suspect itll be also be fine with any double rope in the 6 kn range, keeping in mind that you will get more force on the past piece just like a single or twin ... i suspect that they simply have a more realistic view than their competitors ... or dont play the marketing game as rating a rope as everything under the sun
the solution of course is to get a rope rated as double/twins ... or a mammut double