This blog post is restricted to gear freaks! If SRT bling is not your thing you can skip reading this one.
Treetools is fielding questions regarding the use of the ART Spiderjack and the Rope Wrench on a single rope.
In theory, the doubled rope ART mechanical devices should work on a single rope with the Rope Wrench since the principles remain the same - the mechanical device replaces the friction hitch.
But initial tests conducted by Treetools climbers seem to favor the ART Lockjack over the Spiderjack in this application.
The reason for this is not immediately apparent but it may have something to do with the way the rope runs through the Spiderjack when used in conjunction with the Rope Wrench.
The 'cam release' movement in descent is slightly different on the Lockjack to that of the Spiderjack.
The Lockjack mechanism descends by rotating the device using the distinctive Lockjack 'toggle'.
Rope tension, produced in the climbing line when your weight is applied, and your bridge attachment act as the anchors against which toggle pressure can be controlled.
The release of friction, when the toggle rotates the device to release the cam, allows the climber to descend.
The Spiderjack on the other hand employs a 'release and control' movement for descent with your thumb feathering the wooden block to control friction and therefore speed of descent.
The additional friction produced by the wooden block and the overall direction (rope bend) of the climbing line when used in conjunction with the Rope Wrench does not appear to be optimal for working SRT.
We'd be interested in hearing more comments on this subject.The YouTube clip above shows Ian Flatters using the ART Lockjack in conjunction with the Rope Wrench and it seems to work pretty well.