[ Top | Version B | Return to L.C. Ascenders ]
The Petzl Shunt is truly a unique ascender. It and its copies are the only type 2 lever cam ascenders in my collection.
The shunt uses a stamped aluminum frame that wraps around one or two ropes. A lever is mounted in the center of the frame, and can be pulled through the back of the frame to allow rigging the rope. The lever is spring loaded so it will automatically return to the operating position. A 10 mm round pin passes through the lever. In use, it presses the rope into a slight detent in the frame. There is a small hole in the back of the lever that one can attach a small cord to to allow remotely releasing the device, but I can't think of any serious reason to use this. Aluminum blocks on each side of the frame provide some support for the frame and the bolt that serves as an axle for the lever.
The shunt can be used on double rope (but only if both ropes are the same size), and with care on single rope, although single rope use puts an asymmetrical torque on the lever. For some curious reason, the Petzl literature recommends ascending with only one ascender (attached to the seat harness), and wrapping the rope around the foot as a substitute for a second ascender. In an emergency this works, but I hardly think is the safest possibility. The shunt can be released under load by pulling down on the shell. This is easily done, and with only one ascender, one could easily get into trouble.
Petzl also recommends using a shunt as a rappel safety on double rope. I don't believe in rappel safeties for a number of reasons, so I can't recommend this either.
Petzl also suggest using the shunt for top rope belays, but I recommend using a good belay device instead.
[ Top | Version A | Return to L.C. Ascenders ]
Version B differs from version A in several small details. The frame is now finished with Petzl's ugly "bird droppings" finish. The lever is a somewhat cruder forging with a few differences in detail. The side pieces are now stamped from steel, and they wrap around the frame, giving it more support. The bolts are now hex-head, and may be slightly larger, but I'd have to disassemble mine to find out for sure.
[ Top | Version A | Version B ]
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©2007, Gary D. Storrick