There are two approaches to this and which you take depends partially on the size of the vehicle, and partially on your approach to life.

Unbogging a small vehicle like a Suzuki Sierra is rarely a drama. Given a hi-lift jack and a few boards, and you should be up and away with ease. But it’s a different matter with an OKA, let alone the multiple tonnes of a big Hino or MAN 4WD motorhome.

The other consideration is whether you wish to use 4WD etc routinely to go places where you could not otherwise realistically travel – or to use such aids to get yourself out of strife before you need to seek outside assistance (if any is obtainable). Consider this one seriously as some of the more macho Hemingway types see a thorough bogging as a sort of bull-fight with less risk of being gored.

Based on rather more experience of these situations that I probably need, I recommend the inexperienced to start with the cautious approach, and then to use experience-based discretion to know when, for example to engage 4WD to explore places that one cannot reach otherwise.

It is also necessary to acquire some feel for the stresses on the transmission when attempting to get out of (say) deep sand. This is particularly true of big 4WD trucks as these have huge torque multiplication in low-range first gear. Big trucks may seem unbreakable. They aren’t!

Despite the above however, if you intend to go off-road in isolated areas I seriously suggest a minor trial bogging or two somewhere where help is available if needed. Or ideally with an experienced 4WD owner and his vehicle to assist if necessary. Another suggestion is to complete an accredited 4WD driving course.

How Bogging Occurs

Bogging happens when the surface is unable to support the weight of the vehicle sufficiently for it to be driven forwards or backwards by the road wheels. This readily happens in soft sand and, unless tackled correctly, the wheels may then be spun deeply into the sand until either the engine is unable able to turn them any more, and/or the vehicle sinks to chassis level.

Mud tends to result in a combination of sinking and lack of grip. Each situation requires its own and different technique, both to avoid and to remedy.

In both of the above, a major problem with road vehicles is the so-called differential. When a vehicle corners, the outside wheels traverse a larger radius than the inner wheels. To do this they must turn more. This is not a problem for un-driven wheels – each spins on its own axle. But driven wheels need some device to enable one to turn faster than the other whilst still transmitting drive.

The above is the role of the differential, a mechanism in the drive axle/s that enables the outer wheel to turn faster than the inner wheel whilst sharing the drive force between both. On normal roads, all works fine. If however either of the two normally driven wheels looses grip, then all drive to the opposite wheel is also lost.

This can be partially overcome with vehicles that have handbrakes operating on the rear wheels) by applying the handbrake (NOT the foot brake) just sufficiently to brake the spinning wheel but not so hard that it prevents the other wheel from turning. This enables drive to be shared once again by both wheels. This may seem crude but it’s exactly how the latest electronic ‘traction aids’ work!   

Sand

The odd few metres of sand or bulldust can usually be overcome by the vehicle’s momentum. Tackle it at about 25 km/h and you should get through. If longer, walk through it first to check that it does not become softer further along. Do not drive faster than 25 km/h or if you are in soft sand or you will have further to reverse out if you do get stuck.

If close by water, check to see if the water table might extend under the sand (as last month’s The Wanderer correspondent “Budget” Barry Powell, T43838 found out the hard way). This is better established by digging a deepish hole (and filling it afterwards!) – rather than having a road wheel inadvertently serve that purpose.

I’m personally opposed to vehicles driving on beaches but if you really must do the following.

1. Drop tyre pressures to about 30 psi and use 4WD, (with the hubs locked where applicable).

2. Avoid driving on beaches at extremes of tides – and never on an incoming tide. (Be aware that Kimberley tides can exceed 10 metres).

3. To turn around on a beach climbs slowly away from the water and make your turn toward the sea – never away from it. That way you are not attempting to climb steep sand whilst close to the water.

4. Make very wide radius turns (a vehicle can be bogged by turning tightly).

5. Be wary of towing a trailer on the beach. If you do, drop its tyre pressures as well.  

Where there is only occasional sand, keep tyre pressures normal or about 20% less. Use 4WD drive if necessary (but do not engage the diff locks). Drop down to first gear high range or second gear low range if necessary but do not let the engine labour. If the engine does begin to labour, and you really have to proceed forward, drop tyre pressures to about 30 psi.

If you get bogged, stop the engine the instant it happens. Do not let the wheels spin even slightly. If the car is bogged spinning the wheels always makes matters worse.

Take your time over the following.

With the long handled shovel you have remembered to pack (!) remove all sand in front of, behind and the path in between the tyres. Cut that path to the same level for about ten metres behind the vehicle. Ensure all parts of the vehicle’s underside are well clear of the sand (particularly under the differential housings).

Drop the tyre pressures to 25 psi.

Ensure the front wheels are pointing absolutely fore and aft. If the vehicle moves keep going in a straight line – if you turn even slightly you are likely to dig yourself in again.

Select reverse gear low range 4WD and with extreme care see if the vehicle will move. Do not allow the wheels to spin even momentarily. The vehicle will either be drivable out or it will not. If safely possible, see if you can actually see the driver’s side rear wheel. Even the slightest inching of that wheel without vehicle movement makes matters much worse. If you have a helper, have them watch all driven wheels. If any spin, and you have a diff locks, then engage it/them now.

If the vehicle still does not move, drop pressures to 20 psi and try again. Given the above track preparation, almost any vehicle can be driven out of sand using tyre pressures between 20 psi and 16 psi (the tyres act much as caterpillar tracks at such pressure).

If the vehicle will still not budge you are either not preparing the track sufficiently or you have got into exceptionally soft sand.

At a last resort do all of the above, but also jack up each wheel and pack what ever you can find that is at least firmer than the sand under the tyres. If you can find a couple of really thick logs, placing these between each tyre of a twin rear-wheeled vehicle works very well. But you need big logs as small ones may wedge between the tyres.

Never rush any of the above. Like cooking, success depends substantially on good preparation.

Once clear, reinflate the tyres if feasible. Otherwise keep the speed under 30 km/h, and avoid any sharp turns, until you can restore normal pressures.

Mud

Whilst sand is never that much of a concern to an experienced off-road driver, mud is a different matter altogether.

Often, much depends on your tyres. As a general rule, narrow large diameter tyres are more effective than wide tyres. The former tend to dig down to an often firm surface a few centimetres down, the latter tend to semi-float and lack traction.

More so than with sand, it’s usually better to avoid getting bogged in the first place. Never (for example) ignore a notice advising a road is closed by flooding. Getting fined $500 per axle may then be the least of your concerns.

Be very cautious on dirt roads that are flooded in their middle. More often that than not there will be a firm bottom under that water. Take time out and walk it through. Be careful about going off to the side – that’s how most get bogged. I know – I’ve done it!

Driving on muddy tracks needs to be tempered by whether or not you have a winch and whether or not there any trees or heavy enough vehicles that can be used as an anchor.
Even if you have a winch, it tends to be more useful for assisting others more than oneself – unless it’s at the rear of the vehicle, or you have a winch at either end or a portable unit.

The most useful device to have is a Hi-Lift jack. These can lift one corner or the whole side of a campervan (but not a heavy motorhome) by close to a metre. You’ll need a large and solid base plate to stop it driving itself into the mud – but once in place the jack will lift the vehicle high enough to insert rocks or logs under the tyres.

Here again, thorough preparation is the key. Take half a day if necessary, but get that vehicle onto a firm made-up surface, extend that surface well behind the vehicle and then drive it out in reverse. Dropping tyre pressures usually helps, but not the extent that it does in sand.

A second essential is a snatch strap. Many 4WD and truck drivers will be willing to assist but are rarely enthused about immersing their $100 plus strap in a swamp. Having your own also shows that although have become bogged, you are not a total off-road nong.

Snatch Straps

Snatch straps are a great invention but also extremely dangerous to be around.

They work like this. If you try to unbog a heavy vehicle by towing, the pull is limited either by the towing vehicle’s power or its grip on the road. Either way, it stresses that vehicle’s transmission.

A snatch strap overcomes these limitations. It is an elastic material that can stretch to close to twice its length, but has a breaking strength of a typical five or six tonne. Its used by attaching it to suitably rugged attachments on both vehicles (never tow balls) with about one of its length slack on the ground. The pulling vehicle then drives forward at a steady 10-15 km/h. The pulling vehicle’s momentum stretches the strap and plucks the bogged vehicle out of the mire. In effect a snatch strap increases the effective force (over a short distance) many times.

Dangers to Avoid

Debogging a vehicle is potentially dangerous: jacks may sink or move sideways, cable breakage can kill. Unless well secured, a recovered vehicle may roll forward onto its rescuers.
 
As when winching, keep bystanders well away. Huge forces are generated and can wreak massive damage if anything breaks loose. Towballs are particularly dangerous. The forces are quite high enough to snap their base. If that happens they become cannon balls and can do at least as much damage. Damaging forces can be usefully dissipated (via air resistance and inertia) by hanging a blanket over the winch cable or snatch strap.

Drink plenty of water, the combination of possible heat plus heavy digging introduces a very real risk of dehydration. Above all, preparation is the key.

A great deal more of information on matters like this is included in Collyn’s The Campervan & Motorhome Book available directly from CMCA headquarters.