Ideally, avoid becoming bogged! This requires a lot of hard experience however, and it is almost inevitable that when you initially drive off made-up roads, sooner or later you will become so. Sand and mud require different approaches but the ideal is to only use low range 4WD and lower tyre pressures to enable the rig to move more easily, never as a last ditch way of getting out of trouble. Travel, at least initially, with another 4WD that can assist extract you if necessary.
Engage 4WD and lock the front hubs (manually if required) the moment you encounter more than a few metres stretch of soft sand. Stay initially in high range. If the tow vehicle begins to labour in third gear (or needs a lot of throttle in the case of an automatic), stop and lower tyre pressures to 175 kPa (about 25 psi). If all feels well, continue in high range.
If the above happens again in second gear, drop pressures to 140 kPa (20 psi) and keep going only whilst the rig seems to be moving easily. If it begins to labour in second gear that’s the time to be cautious, particularly if travelling alone. It is also the time to stop and check the track ahead. Unless it seems firmer, try and find an area where you can make a very wide radius turn. If all seems well, turn and go back the way you came – driving in the ruts you have just made. If a turn is not feasible, carefully reverse out in the ruts until a 1800 turn can be made safely.
More experienced drivers may consider continuing further in low range. If the vehicle begins to labour in low range second it is time to think hard about going any further as major stresses are being imposed on both engine and transmission – with real risk of breakage, not just bogging, in low range first. The rig will have more flotation with the tyres dropped to 115 kPa (about 16 psi) but it is best to keep that (and low-range first), for vehicle extraction. After that there are no more options.
If bogged, do not allow a tyre to slip, let alone spin, even for a fraction of a turn. It is never possible to debog a vehicle by spinning the tyres. They always dig it in deeper. Instead, form a trench in front and between all wheels, taking it down at least the lowest point of the tyres. Make 100% sure the front wheels point straight ahead.
If possible have someone watch the tyres, and attempt to ease out backwards with minimum throttle. Stop instantly any wheel begins to slip. You may then need to jack up the wheels and place the carpets, or anything you can find that provide grips, under the tyres.
At last resort, drop pressures to about 85 kPa (12 psi). Make only ultra slow, wide radius turns as there is a very real risk of rolling a tyre off the rim. Reinflate to a pressure of at least 140 kPa (20 psi) as soon the vehicle is back on reasonably firm ground. As in sand, narrow but large diameter tyres are generally preferred – see pages 25/26 as to why.
It is often better to stay on a soft muddy road rather than attempting to go around it. It is more likely to have firmer underlayers. If in the least doubt, get out and test – that’s far better than trying to get the rig out of a bog – because if seriously so, you may have to await assistance.
Debogging from soft mud is a filthy and often lengthy job. It can only be done by using whatever you can find to support the jack – and lifting each tyre off the ground, digging the mud away to about 150 mm down and packing in as much firm material you can locate. Then preparing a firm path that enables you to hopefully reverse out.
ARB recovery strap. Pic: ARB
Earlier ways of de-bogging a seriously stuck vehicle, involved winching, or pulling by another vehicle, but were limited by the power of the winch or the power and tyre grip of the tow vehicle. So-called snatching out, is now a more or less routine way of recovering bogged vehicles. It is extremely effective, but an inherently dangerous technique. It necessitates knowledge and actual experience that needs acquiring by completing an authorised off-road driving course. It is included here, not as a guide of how to do it, but to emphasise and reinforce the considerable risks involved.
A snatch strap acts like a catapult. The elasticity of the special strap used stores the kinetic energy of the accelerating recovery vehicle. This enables it to exert a force many times greater than a direct pull. It works much as did giant catapults in olden times that could hurl half tonne rocks over 100 metres.
The danger, and it is only too real, is that if whatever that snatch strap is attached to were to break, the massive pent up forces in the tightly stretched strap can (and do) catapult broken bits of heavy metal at the bogged vehicle with almost unbelievable force.
Snatch straps usually make an otherwise difficult recovery relatively easy, even in deep mud; but if misused, are literally as lethal as medieval cannons.
Take this ultra-seriously – people have literally been killed doing this because they do not realise the huge forces and energy levels involved.
Using a snatch strap
Warn snatch strap and towing hook. Pic: Warn Industries.
A snatch strap’s semi-elastic webbing has a typical breaking strength of 12 tonne. It must be attached to the rescue vehicle and the bogged vehicle via shackles that are officially rated at twice that strap’s tensile strength.
Do not even think of using the non-rated shackles sold by hardware stores. They can literally kill if they break, and (sadly) have.
Shackle – rated to AS 2741. Pic: ARB.
The shackle must be attached to either vehicle by equally strong engineered eye bolts, or by a method that can be totally relied upon to be very much stronger than that strap and shackle.
Ideally have a certified engineer design and arrange to fit suitable attaching points for the snatch straps on the front and rear of your tow vehicle and also to the front and rear of the trailer.
The snatch strap must be attached to the two vehicles as outlined above.
Never, attach that strap to the towball. The forces involved can and have torn tow balls out of their mounting and hurled them like cannon-balls for over half a kilometre – sometimes via the windscreen and rear window of the bogged vehicle.
The safety sequence
There are two main risks, one is to anyone standing near or behind the bogged vehicle, the other is to the driver of the bogged vehicle. Firstly dig away any banked up sand, or do what you can to ease movement of the bogged vehicle. Then:
1. Place responsible someone in total charge with absolute priority to keep bystanders at least ten metres to the side, and children at least 50 metres away and carefully watched. Ensure no-one is behind the bogged vehicle – for at least 500 metres.
2. Connect the two vehicles together in a totally straight line, and such that a two metre length of snatch strap is left loosely lying in an S shape about half a metre to a metre across, on the ground.
3. Place a heavy blanket, or one of the devices made for this purpose, folded over so as to enclose the centre of the strap. This assists to reduce some of the force should the snatch strap break.
4. Start the engines of both vehicles. Select the bogged vehicle’s first gear with clutch depressed (or select Drive if it is an automatic).
5. Release the hand brake of the bogged vehicle.
6. Drive recovery vehicle away and up to a brisk walking pace, in first gear and in a straight line.
The moment the bogged vehicle begins to move, release the clutch and accelerate gently.
If the above fails, do what you can to free up the bogged vehicle (see page 85) – and try again. Do not allow the recovery vehicle to exceed a fast walking pace, of about 5-6 km/h, or there is a probability, not just possibility, of breaking the snatch strap.
Renew the snatch strap after ten uses.
The author again stresses the very real need for safety and expertise in every aspect of using these effective but potentially extremely dangerous straps.
By far the best way is to enrol in one of the accredited off-road training courses run by TAFE and some 4WD clubs. Ensure they are accredited.
(The above describes only part of the safety precautions required, It is thus intended only as a description – it is not a guide.)