The Singing Tree Rope Wrench is slowly making its presence felt in the New Zealand tree climbing market following extensive promotion out of the United States.
The Kevin Bingham designed device allows for ascending and descending on a stationery single line when used in conjunction with a suitable friction hitch - without the Rope Wrench the hitch would bind up and not work efficiently on a single line.
Retailers of the Rope Wrench typically caution users about SRT and suggest they be suitably qualified in single rope climbing techniques.
One issue though, perhaps not immediately apparent, is at the point of changeover when using a single rope.
A potential problem can occur when a base-anchored, lowerable single line is set through a crotch. If the climber wants to extend the line on reaching the top anchor point there is a tendency to climb up into position before lanyarding in.
Obviously this practice is not ideal and should be discouraged at all times but we are dealing with reality here.
When a climber performs this same maneuver using a doubled-rope configuration the rope is looped completely around one of the stems, securing the climber with one connection point. If the climber was to fall during the changeover, it might be unpleasant but they would not plummet to the ground.
When the same scenario is applied to the single rope set-up (as used with the Rope Wrench) the climbing line is not looped around the branch which means the odds are 50/50 either way.
Loosely translated… if you happen to fall on the wrong side of the branch (before you manage to set your lanyard) its goodnight nurse!
Have a close look at the photograph below and you'll see exactly what we mean.
Perhaps this is another example of the 'gap' in tree climbing knowledge Andy Harrison referred to at the WINTEC Best Practice Guideline
Its not to say there is an inherent problem with the Singing Tree Rope Wrench - you just need to be sure you are suitably qualified and have the right experience to use such equipment - and keep your wits about you during a changeover!Photograph kindly supplied by Drew Bristow, DB Tree Splicing