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Heavy KERR Recoveries
When a Recoverline KERR rope is used to recover a fairly stuck load, this is where the 'kinetic energy' that is stored up in the nylon rope does it's job.
The energy is created by the speed times the weight of the recovery vehicle. As the rope is literally stretched to its maximum being pulled towards the recovery vehicle, much like a powerful elastic band!
Imagine a well stuck vehicle. Always use a bridle made from 3 strand 24mm diameter nylon rope about 2 metres long with soft eye splices at each end. Attach this bridle to the stuck vehicle after rigging it through the protected eye splice of the KERR rope. NEVER EVER rig a shackle directly on to the end of a KERR rope.
If that shackle should break through blowing apart you would have a flying missile which would travel back along the length of rope towards the recovery vehicle and embed itself through its tailgate or rear window which would be exceedingly dangerous.
The same goes if a towing or recovery point fails, please refer to my last chapter on safety issues. I digress, back to attaching the bridle to the front of the stuck vehicle to those strong Jate Rings, 'Bumper D Rings' or Jackmates. Here you can use shackles, as by using one at each end of the bridle you are halving the load and protecting the chassis rather than yanking the stuck vehicle from one side only.
The shackles need to be not less than 20mm (3/4 inch). Some will say that you must only use 'tested' shackles, but in general terms a 20 x 20 mm (pin & body) is good for about 3.25 tonnes SWL (Safe Working Load) times the recognised safety factor of 6 gives you a capacity of nearly 20 tonnes. I've never broken a shackle yet and I have got to admit I've done one or two pretty daft things!
Snake the KERR rope on the ground as shown in the pictures and attach the other end to a good central recovery point. Yes, you could use a bridle that end too, or use a safety rope as shown as well. But in my experience, a good well fitted towing unit on a sound chassis is fine.
My advice is to only have one helper as an assistant plus the two drivers in rigging the KERR rope and bridle. All the bystanders to stand clear during the operation and all the passengers must vacate the two vehicles.
Once the two drivers and the assistant have discussed the recovery techniques the assistant stands well clear on the driver's side to confirm they are both ready and signals to the recovery driver to GO. The towing vehicle accelerates to its maximum permitted speed (see table) and snatches the rope at that speed. If the stuck vehicle is only mildly stuck there is no need to assist recovery by having its wheels turning.
If however the stuck vehicle is really well and truly stuck then that driver should be in gear with the clutch depressed just prior to the recovery commencing. Just as the rope becomes taut, let the clutch out with just a little acceleration. Make sure that you don't stall the engine and definitely don't overrun the rope.
The towing vehicle may be slowed or even halted as the Recoverline approaches maximum elongation. It's at this point that the kinetic energy is converted into the potential energy of the stretched rope. This build up of energy is transferred by the rope to the stuck vehicle.
(c)Goodwinch Limited 2006
