A snatch strap stores kinetic energy to ‘fling’ or ‘snatch’ a vehicle from a bogged situation. The energy is put into the strap by the towing vehicle driving away and stretching the strap. When the energy stored in the strap reaches a level graeater than the resistance created by the bogged vehicle, the vehicle is pulled from the bog. This is a more gradual method as the strap stretches to avoid instant delivery of the force or “Shock Loading”. Many people believe that the stretch component of the strap is gentle on vehicle recovery points and therefore is safe to use. This is not necessarily the case because the load placed on the strap from a moving vehicle can be extreme and well beyond the loads of the designed fixing points on both vehicles. It is common for straps that have a breaking strain of 8000 kilograms, to snap.

Click to view a Snatch Recovery

The main reasons for high risk associated with snatch strap recovery relate to:

·         Two vehicles are required for snatch strap recovery. Air Jacks and MaxTrax allow for a single vehicle/single operator recovery with reduced risks – therefore a better option and one that is deemed to be best practice.

·         Approved and engineered fixing points to both vehicles for snatch strap recovery use are required. Note that the original vehicle hooks are generally not rated for snatch strap use, they are for rolling resistance towing and tie down points only. Tow bars may be rated at 3000kg but again this is for a rolling mass of 3000kg, not a bogged vehicle that can be 3 times its normal mass (ie 9000kg).

·         Roo bars are for impact forces and not generally as a fixing point for towing of any kind. There may be an exception to this if an electric winch is fitted but again, the best winch is only rated at less than 5000kg. It is not uncommon for the entire tow bar or roo bar to come flying back at the operators resulting in death or serious injury.

·         It is generally accepted that if a fixing point breaks during a snatch strap recovery that the item will be travelling in excess of 300km/h towards one of the vehicles and their occupants.

·         The maintenance and quality of the strap is difficult to maintain at the highest standard. Who cleans it after use, dries it, checks it for damage, stores it out of UV light, etc?

·         How does an organisation ensure that all vehicles involved in the recovery will have approved recovery points? Usually the recovery is arranged with any vehicle found to be available.

·         Ensuring that other safety precautions are always conducted is difficult and almost impossible. We advocate that two fixing points be used on both vehicles. Then a 10000kg bridle strap be attached to both points on each vehicle to share the load and act as a brake should one fixing point break, and that at least 3.25tonne WLL shackles are used and a dampening device be used on the strap to keep it low in case it breaks.

·         The likelihood of something going wrong is extremely high and the consequences are fatalistic. The Mines Act or any State based Occupational Safety and Health Act requires the organisation employing staff in an environment, where they may use recovery equipment, to take measures that would eliminate or reduce this risk – thus the banning of snatch strap use in many workplaces where safety is paramount.

·         All staff using a snatch strap for recovery need to be trained in its use and maintenance.

·         Snatch straps are not for high momentum use. They should only be used with enough momentum to recover the bogged vehicle. Unfortunately most users simply overload all their equipment by recovering at high momentum and therefore high risk.

How does an employer control this within the workplace?

It takes the “average” human approximately .66 of a second to visualise something and make a three dimensional interpretation of that visualisation. At 60Km/h a vehicle and its passengers are travelling at 16 metres per second, this means you can receive enough accurate information from your eyes, to make one decision for every 10.5 metres of travel at 60 Km/h.

If immediately after that 10.5 seconds you determine that you need to perform an emergency stop, it will take you about 1.8 seconds to react, which means you will take 1.8 seconds to see the object, recognise it as a danger, remove your foot from the accelerator and place it on the brake, and then you can commence your braking procedure. That means you have travelled another 28 metres before you start to brake, and that’s only at 60Km/h. An average 4 lane intersection is 28 metres across, or half of an Olympic size swimming pool.

We can manage this risk by looking well ahead and getting a big picture of our surroundings. At Shawsett Training we teach participants this technique so that they have time to assess and anticipate any hazards that may have an impact on their wellbeing.

Unfortunately, with the trend of driving too close, many drivers only see the back of th car in front of them, and do not observe all the other potential dangers and risks around them. Research conducted by Leonard Evans and published in “Traffic Safety and the Driver” demonstrates clearly that excellent forward vision and a high level of risk perception are associated with safer driving techniques.

For more information on Eye Characteristics in Driving or Risk Perception, please contact us at admin@shawsett.com.au .

A new tyre with the maximum tread depth can pump out somewhere between 8 to 12 litres of water per second per tyre. This depends on the tread design and compound of the tyre. The better the tyre, the better the performance. When the tyre is half worn its ability to pump away water is reduced to 4 to 6 litres per second per tyre and when it is at its minimum tread depth, expect about 1 litre of water per tyre. This is important information because it determines how well your vehicle will brake and steer in the wet. Emergency Services change their tyres at 3mm tread depth to maintain a level of safety.

Every tyre has ‘tread wear indicators’. Have a close look at the side wall of your tyres. You will notice that at even intervals around the tyre there will be small triangles, or the letters ‘twi’, or the manufacturers symbol. Across the tread face in line with these markings will be a raised section of rubber within the tread. This raised section is 1.5mm above the base of the tread. Once a section of these bars touches the road the tyre is now illegal. It is best to replace tyres before this time.

Do not take chances with your tyres. It may have an impact on your wellbeing or your vehicle insurance may be at risk.

So what is the correct TYRE PRESSURE for your vehicle?

A vehicle manufacturer has to provide a placard in each vehicle with their recommended tyre pressures. This placard is generally located in the driver’s door area, glove box lid, or fuel filler cap. The manual will definitely have information on tyre pressures.

When you find the placard it may have different tyre sizes with light and heavy loads for the front and rear tyres. Check the side wall of a tyre to see what size it is, it should have something similar to – 195/65R17. Reference your tyre size to the placard to find out the
recommended tyre pressure for a light load, generally 3 people or less and city driving, or a heavy load, more than three people with luggage or highway driving. This pressure may be in Psi, Kpa or Bar. Read the placard carefully to get the right pressure.

The pressure given on the placard is called ‘COLD’ pressure, that is, before the tyre is warmed up through the act of driving. An underinflated tyre driven for 5Km to a service
station could increase in pressure by up 10Psi. Effectively you may be driving on underinflated tyres if you drive to the service station to check the pressures. Example: your tyre pressures are at 26 when you leave home, drive 5Km to the service station and at the air bay the pressure reads 36, but the placard states 32, so you let 4Psi out meaning that next morning when the tyre has cooled, your tyre pressure is at 22, when it should be at 32.

How do you overcome this? Buy a tyre gauge at an auto outlet, get a good one, it will last and be more accurate. Check your pressures in the morning before you drive, say once on a
weekend, and you will know how much you need to increase your tyre pressure by.

Now you will get better tyre life, better fuel economy and more importantly, better stopping and steering ability. A small effort for a huge gain in your wellbeing and safety.

Check your tyres at least monthly, preferably weekly.

Some organisations working with Shawsett for effective truck recovery have banned the use of truck snatch straps in their workplace and now use a combination of decreased tyre pressure and MaxTrax as an engineering method of reducing the risk associated with truck recovery.

Truck tyre testing conducted by Shawsett has revealed that different tyre brands have dramatic differences in traction and side wall flex. This has a direct impact on braking, steering and off road ability. It is therefore imperative that truck owners select tyres that are suitable for the intended purpose and perform as required.

If the tyre pressure is lowered to increase the tyre to road contact surface area in off road situations, the  speed must be reduced accordingly to prevent tyre damage, keep effective steering control and maintain safety standards. If you require further information on the causal and contributing effects of tyre pressure please contact us at admin@shawsett.com.au

A badly bogged 4WD can require up to 3 times the mass of the vehicle to free it. In other words a 3 tonne vehicle could require a force of up to 9 tonnes to successfully recover it.
Shawsett testing has indicated that a load of 4 tonne is exerted on a 2 tonne 4WD bogged to the chassis rails in dry sand during a snatch strap recovery.

These forces are extreme and there is a high risk of personal injury or property damage. DO NOT attempt to use equipment that you are not trained to use or damaged equipment.

Recovery methods involve lightening the load (equipment and people), ramping the wheels (digging and removing obstacles), lowering tyre pressure, towing with a tow strap, using a snatch strap, lifting the vehicle and improving the ground under the tyres for traction, using MaxTrax, Exhaust Jacks, Hi lift Jacks, hand and electric winches.

Sometimes the people involved in the recovery are agitated, become fatigued and dehydrated. Monitor these conditions carefully and take your time to ensure your safety and that of other people in the vicinity.

Shawsett Training does not recommend the use of snatch straps as a first option, due to the high risks involved and the necessity for another vehicle to assist. We believe the use of
single operator equipment such as exhaust jack, MaxTrax, and shovel are sufficient for a single operator to recover a seriously bogged 4WD in a relatively safe manner.

Shawsett has training courses and Working Procedures for the use of recovery equipment. For more information please email us at admin@shawsett.com.au

The Recovery Strap then allows a vehicle to use a “run up” and develop more energy to pull a vehicle from a bog.

It is generally accepted that a 4WD bogged to the chassis rails requires approximately 3 times the mass of the vehicle to free it. It therefore follows that a 3 tonne vehicle could
require a force of up to 9 tonnes to successfully recover it.

Shawsett testing has indicated that a load of 4 tonne is exerted on a 2 tonne 4WD bogged to the chassis rails in dry sand during a snatch strap recovery. In wet mud the
suction effect would dramatically increase the loads on the equipment.

Shawsett Training recommends that you should be trained in the use of snatch strap recovery principles if you are to be involved in the recovery of a bogged 4WD using this method.

Never use a tow ball, roo bar, tow hooks or suspension components to attach a snatch strap to a vehicle as they are not designed for these loads. There are many recorded deaths resulting from such actions. It has been calculated that a tow ball can travel at speeds
in excess of 160Km/H if broken during a snatch strap recovery. Imagine being hit by that!

 

At all our training sessions we use rated recovery points that are fixed to both layers of a chassis rail with at least 2 x M12 8.8 high tensile bolts to each recovery/fixing point.

Minimum two points to the rear and two at the front.

If required, 3.25 tonne WLL rated shackles are used at the recovery points to attach a 10 tonne rated bridle strap that will share the load between the recovery points. If one recovery point fails the bridle strap will be restrained by the second fixing and thereby prevent a potential missile.

For further information or a sample Work Procedure for the use of a Recovery Strap, please email us with your details at admin@shawsett.com.au

Australian research shows that ESC reduces the risk of:

• Single car crashes by 25%
• Single 4WD crashes by 51%
• Single car crashes in which the driver was injured by 28%
• Single 4WD crashes in which the driver was injured by 66%*

In Australia, single vehicle crashes accounted for 399 fatalities in 2003 (44 per cent of total fatalities), more than the number of fatalities from multiple vehicle crashes.

The US based Insurance Institute of Highway Safety (IIHS) studied the effectiveness of stability control as a road safety measure. The study released in October 2004, showed that based on all police-reported crashes in seven states over two years, ESC was effective in reducing fatal crashes by 34 per cent.

The study also found that ESC benefits are most prevalent in single vehicle crashes. Examples of single vehicle crashes include roll-overs and impacts with rigid objects such as trees.

How It Works

ESC works by using sensors that detect the difference between the direction that the driver wants a car to go (steering wheel sensor) and the actual direction of the car in response. This is done by comparing the speed of all the wheels.

ESC uses the ABS brakes and traction control components already installed into a vehicle. Wheel speed sensors communicate data to a central computer and respond to signals by applying differing brake pressure to individual wheels.

Steering angle and vehicle direction sensors monitor the intended vehicle direction, and communicate to the ABS when differing brake pressures are required to assist the vehicle to track to the internded path. Engine power reduction is also applied to reduce speed. It is important to note that the advantage of differing brake application is only achievable with ESC, otherwise a driver can only apply even pressure to all wheels.

Some ESC systems will intervene sooner than others, and some vehicles are fitted with switches so the driver can switch the system off. This is valuable in the case of Four Wheel Drives in off road conditions.

ESC is of assistance to the driver in:

• correcting impending over-steering or under-steering;
• stabilising the car during sudden evasive manoeuvres;
• enhancing handling on gravel patches, such as road shoulders; and
• improving traction on slippery or muddy roads.

Not all ESC systems are identical. The hardware is similar, but there are
variations in how ESC systems are programmed to respond once loss of control is detected. Naturally, the degree of effectiveness of ESC is dependent upon the amount of traction between the road and the car tyres. Therefore on a car with old, worn or inappropriate tyres, ESC will be less effective than on a car with new tyres or tyres specific to a road environmental condition.

Source referenced: howsafeisyourcar.com.au

Side Impact crashes are particularly severe as there is little protection offered by the side of the car, especially when compared to the protection offered by the front of a car in a head on crash. The front of a car (or rear) provides a much greater crumple area which allows for impact absorption.

In 2009 in the U.S. 27% of driver fatalities were caused by side impact crashes. Some studies have suggested that if side airbags were fitted to all vehicles, it would result in approximately 1000 less fatalities and 1000 less severe injuries.

The American society of Epidemiology comments that Side Impact Bags can reduce fatality rates by 30% for side impact crashes.

In Australia, 2005 Road Safety Figures showed the cost of a fatal crash to the community to be in excess of $3 million.

A side impact airbag deploys within a twentieth of a second, to provide a cushioned protection from the head and chest striking the “B” Pillar and door of the car.

We utilise the side impact bags as a control mechanism for our exposure to crash related risks, but only as a lower order control.

Our risk control measures for driving have always had observation and avoidance as the major control measure influencing the likelihood of a crash occurrence.