Pulley Efficiency

Recently, we were asked for input by Rope & Rescue for their blog post about Pulley Efficiency. After reading their post a few comments came to mind:

Ropes twisting is mentioned briefly and the resulting efficiency loss can be dramatic.  Not many climbers realize that the gain of a 4:1 mechanical advantage can be fully lost due to some very minor operator errors.

In our tower climber training courses we also suggest always making “main line or pickoff connections” in a rescue scenario before removing the patient’s current attachments while hoisting them with a 4:1 haul device such as this one.  Although it is rated as a life safety connection, the rescuer must still ensure proper technique to not let go of the control line in the “free wheel” mode of the raising device.  This minor error could cause a slight unintended descent of the patient and further complicate the situation, possibly causing further injury.

With proper techniques, we see 4:1 devices such as this one essential tools in a rescue kit for today’s tower technician.  Having a raising system pre-rigged can be a critical life saving device in a given scenario.

Prepare and prevent, don’t repair and repent!