One of the main items of recovery gear used in extracting vehicles from bogs is the snatch or recovery strap. These straps should be carried at all times when venturing off-road.
Snatch straps are made of loosely woven nylon and they’re relatively economical to buy. The recommended combination of a strap and two bow shackles should set you back between $90 and $130.
In contrast to winch or tow straps, which are stiff and non-pliable, snatch straps are soft, supple and easy to handle. They have a stretch factor of around 20-30%, which allows energy to be transferred from the towing vehicle to the bogged vehicle. This reduces the load or effort required by the towing vehicle, as well as reducing the impact or load that would be applied to the extracted vehicle if a conventional static strap, such as a tow strap, was used.
The transfer of load when using a snatch strap means that a smaller, lighter and less powerful vehicle is able to extract a much larger and heavier one.
The snatch strap has sewn reinforced eyes at both ends which allows it to be joined and/or connected to the vehicles involved in the recovery. These straps have great potential to cause damage or harm if used incorrectly, so all good snatch straps have overload safety indicators and warning tags attached.
Snatch straps vary in length and strength according to their application. The 8m/8-tonne strap used to be the most common kind, but the trend towards larger vehicles, loads, more extreme locations and towing trailers has seen the 8-tonne strap give way to stronger straps ranging from 10m/10 tonnes to 15m/15 tonnes. Even larger units are available for trucks.
Remember that snatch straps should not be used for general long-distance towing. This will damage the strap and dramatically reduce its elasticity. It can also can cause danger and trauma as the towed vehicle is accelerated forward (and thence back).
A good strap can withstand forces more than four times that required to extract a vehicle under reasonable conditions.
However, while a strap can be rated at 8000lb and actually fail at 8000lb, (most fail at loads up to 40% more than their rating), breaking loads when tested vary greatly. So make sure you check out the ‘tested’ evidence when buying a strap.
I am often asked why more lowly-rated bow shackles can be used with more highly-rated straps. This is because bow shackles are rated at up to six or seven times less than their breaking load, and as such they form the strongest part of the equation.
Use bow shackles, not D shackles, because bow shackles are shaped to minimise wear and tear to the snatch strap. In general, 3.2-tonne shackles are used with 8-tonne straps while 4.75-tonne shackles are used with the larger straps. Check that the shackles are rated and certified as such.
Read up on how to use snatch straps and practise using them. In general, use what is called the 2m rule – leave about 2m of the strap or about 20% of its length loose. This results in a load of approximately 2-3 tonnes being applied, which will not damage the strap, cause failure and/or damage to the vehicle.
Even then, loads of 8-10 tonnes can be applied at peak usage. Leaving too much strap loose multiplies the load, especially if the extracting vehicle accelerates too quickly. This can cause the strap to fail and/or cause vehicle damage. Tow points can separate from the vehicle and become dangerous missiles. I have witnessed the complete separation of the front end of a vehicle, including bull bar and winch, due to incorrect use of a snatch strap.
Make sure the recovery points on your vehicle are able to take these loads, and do not confuse vehicle tie-down or shipping points with recovery points. If your vehicle does not have any recovery points, have them installed by a reputable 4WD accessories outlet.
Lastly, remember that snatch straps are intended for straight-line pulls. Extractions around corners and/or around obstacles such as stumps, trees or rocks require tow straps or a chain.
• Assess the total situation. Is the use of a snatch strap in this situation within safe limits? Is the bog so serious that another method should be used – drag chain, tow strap or winch? Assess all hazards and obstacles that could cause a problem for the recovery.
• Prepare the area. Clear excessive sand or mud away from the wheels and under-body of the bogged vehicle. If necessary, create a ramp for the bogged vehicle and drive the recovery vehicle backwards and forwards if in soft material to create a firm surface. Bog mats could be used to increase traction.
• Check everything. Check the tow points of both vehicles for strength. Check the strap – especially someone else’s – for damage. Do not use a damaged strap. Attach the strap to the hook or to the eye of the tow-point with a shackle. Back the shackle pin off a quarter-turn to avoid having it lock under load.
The pin of a square-section towbar receiver may be used – loop the eye of the strap into the receiver and pass the pin through the eye and secure with the clip. Towbar manufacturers warn against such use for their own legal reasons.
• Position the vehicles. Back the recovery vehicle up to the bogged vehicle using the 2m rule for laying out the strap. Ensure that the strap is not twisted and that it has not knotted.
If the recovery vehicle cannot get near the bogged vehicle without risking being bogged itself, join two snatch straps (thus increasing snatching potential by two) or join the snatch strap to a winch or tow strap (snatching potential remains the same but length is greatly increased). Join the straps using a dowel, stick or rolled-up magazine to separate the straps to avoid the eyes locking during the snatch. Locked eyes are almost impossible to separate.
Safety check. Ensure all passengers are out of the vehicles and that they and all spectators are well clear of the vehicles – 1.5 times the length of the strap away is the general rule. No one should be anywhere near the front, rear or in between the vehicles.
• Communication check. Agree on a method of signalling. Two-way radios are best but, in their absence, the thumbs-up method (thumbs up in the bogged vehicle ready to go, followed by thumbs up in the recovery vehicle to begin) or the use of horns (two horn blasts when ready, followed by one when the snatch is completed and the vehicles should stop).
A single site controller can also be used – this person can use agreed signals to indicate ready/go/stop.
• 4WD mode. Check both vehicles are in 4WD mode – hubs in, centre diff (where applicable) engaged, 4WD engaged, brain in gear (it is important that everyone involved in the recovery is clear about procedures and how the recovery will proceed).
• Select a gear. The recovery vehicle selects second low gear, bogged vehicle the same (or low reverse if the vehicle is being extracted backwards).
• Drive away. With appropriate signals, the recovery vehicle moves off at normal acceleration – about 2000-2500 revs – it’s all about maximising torque, not speed. The strap tightens, the bogged vehicle accelerates simultaneously, and the strap stretches with the recoil ‘jumping’ or moving the bogged vehicle forwards out of the bog.
It may be necessary to repeat this procedure a number of times until the bogged vehicle is clear. Forward movements of 1-2m will eventually see the bogged vehicle free.
• Reassess. If the bogged vehicle remains immovable, alternative recovery techniques will have to be applied – for example, winching or tandem or triple towing using connected tow straps connecting two or more vehicles. Assess the situation carefully and use methods that minimise risk and load.
• Stop. The driver of the recovery vehicle should be aware that depressing the clutch too quickly at the conclusion of the recovery could result in his/her vehicle being pulled backward by the recoil of the strap. You may have to stall the vehicle.
• Keep clear. Ensure that the recovered vehicle does not drive over the snatch strap as this will damage the strap or could result in the strap coiling up around the wheel.
• Tidy up. Detach the strap(s) and shackles and return them to storage. Clean the strap ASAP if it is dirty. Dry the strap if wet. Recovery gear should always be stored in a safe and accessible location. Do not attach snatch straps to the front of a vehicle and then carry the rest on the lap of a passenger or on the front floor. If the strap catches on the wheels a disaster will occur.
All being well, the two vehicles can now proceed on their journey.
The energy stored in an elastic snatch strap is enough to free most vehicles – but there are limitations.
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Use strong dowel, or even a rolled up magazine, to join snatch strap loops so the elastic loops don’t clinch tight around the join.
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NEVER join straps like this, it invites disaster.
Now that’s a test for a snatch strap! Peak loads of up to 10 tonnes can be applied in situations like this so choosing the correct strap rating is essential.Reads: 1067