2:1 in DdRT

[TreeSpyder]

SRT is Single Rope Technique;

DRT is Double/2 Rope Technique;

DdRT has been coined as Doubled Rope Technique.

 

The first 2 are usually non-retrieveable rope setups. But the latter/last is the usual arbo, retrieveable rope technique of the rope folded/doubled over the support. Whereby; 1 end is terminated on the saddle; and the other leg slides through a frction hitch; that (the friction hitch) is terminated at the saddle. Like the 2nd setup in the imbedded drawing; where the climber lifts/lowers self; rather than controlled by a ground man (1st setup).

[FJR]

I just spent some time reading all that and it was excellent as always Kenny.