特殊环境驾驶技巧之沙地驾驶
It is nice, in the morning, to have your standard SSS (shave, shower and shit), but when you wake up in a desert environment, you may have to add another S, for Sand Removal from anything like your air cleaner up to your underpants, to be polite. So, if I am asked a personal opinion, my advice is: stay out of deserts unless you have to work there or have a very twisted sense of having fun. This having been said, some people still feel the uncontrollable urge of desert-suicide-attempt-by-sand, usually implemented by a wrong choice of tires, badly prepared vehicles, breaking vehicle parts, travelling with one single vehicle only, excess speed or just plain getting lost. Ok, it is your life, not mine and I don‘t give a damn.
Tires:
I think that in the whole history of motor vehicles, good sand tires have been produced only once and that was during the last war, when German Kübelwagen of the Afrika Korps were equipped with low-pressure balloon“ tires that had no thread at all. Some other armies may have had them too, but I am not aware of it. These tires performed extremely well.
Nowadays, except for the Michelin xzs, there is nothing much worth talking about on the market, for most other tires are a sorry compromise between road, rock and sand use. Please note that the Michelin performs best in sand when 75% worn and run on about 0.3 bar for a 750/16 in the soft stuff. So if you plan a long trip through sand, try at least to get some tires with a worn thread. Why ? Simply because you want to stay ON TOP of any sand and you DO NOT want to dig in. This is sometimes called flotation“. (I don‘t like to use this word a lot for it being mostly a tavern counter buzzword used by Johnnies wearing their baseball caps backwards).
So what is this flotation“ ? It looks as if it was derived from floating“, much in the way that the lighter floats on top of the heavier. And since Series III density is less than that of sand, this may even apply. Driver density may be the other way round, of course, but that is not the point right now.
So we want to stay on top of the sand, right ? This will not allways work, depending on the type of sand you are attempting to drive over, but at least we can try. The idea is to obtain the largest possible footprint“ with our tires. If your tires are inflated at their nominal pressure, you will have, say, a footprint of x“ cm½. If you lower your tire pressure by half, this surface may become something like 20% larger and if you go for the real good“ footprint, i.e. running at something like 0.3 / 0.5 bar on an appropriate tire, surface “x“ may even double, reducing the ground pressure of your vehicle by half and that is where you want to be. Only tracked vehicles can do better than that. This means that now, with much less ground pressure, you reduce your chance of getting stuck in sand by roughly 50%. Please note that an underinflated tire will run much hotter by the excessive flexing of the rubber (internal friction) and may get damaged by the heat only. So check this whenever you can. Also, some tire sidewalls are not designed for a lot of flexing and may fail by mechanical influence of the flexing alone.
So after that you have the flotation“ issue sorted out and it looks as if your vehicle will not cut its way down to the axles in soft sand within the first few seconds after driving off, it may be a good idea to get going. So load up your gear, cat, kitchen sink and travel companion in your 2a litre and aim for Bahlam-el-Salami or any other sandy destination in Kangarooland.
So now the time has come to leave the tarmacadam, engage your front axle and hit da sand.
Driving in da sand.
Looks nice and feels good, elbow out of side window, 2a litre engine purring away like an Egyptian desert cat, Ray-Ban on face, looking through your split windscreen at just a track leading to far away horizons and your imagination switches to the tales of 1001 nights, Ali-Baba and the 40 unemployed, the great adventure, camel caravanes, Berber tribes, kangaroos and the like. 20 Kms of dreaming later you get stuck because you thought it to be a good idea to leave the track and you hit a patch of fesh-fesh, the almost invisible powdery substance with the granulometry of cement -found in most desert areas of the world-, in which you cannot even walk. (in Australia, the stuff is called bulldust) Heheh. Had to happen. Stay ON the track, dammit.
Also, your first lesson in sand recovery. Where for mud driving, it is a good idea to have your winch in the front of your vehicle (you DO have a winch, don‘t you?) and to pull yourself through that boghole, the contrary is true for the desert, since you dont have all that long a winch cable on the drum and having to dig in (and out) a ground anchor several several times is not exactly my idea of having fun, I think it is better practice to have your winch in the back for desert crap because when you get stuck it usually dont take you very far into a bad spot and winching out backwards may be much quicker and then you can try to drive around the obstacle.
Ok, now you got back on the track and you go on having fun in scorching heat (Yes, even the air temperature is 40° C +) until you find the next soft spot or have been stupid enough to go Dune Bugging. Recovery in standard“ sand is much the same than in the soft stuff. Winching is your best option, followed by shoveling and the use of PMP (perforated metal plates), the things they build emergency airstrips from, but use them upside down for more grip. Step aside when a wheel finds grip on a pmp, for I have seen some being shot from under a vehicle like 20 yards away and you don‘t want that to hit your shins, do you ? For practice, go to the seaside in your own country, find some soft sand dunes, bog your S III in it and then go to play with those pmp. Now imagine the same exercise in 45°C in the shadow, in a place where there is NO shadow. That will give you a good idea of the fun.
Right, so now you got out of that dune foot too and you are back on the track, glad that you made it. It will be evening by now, so go find a place to set up camp, have some food and try to get some sleep. If you can, sleep IN your vehicle (Annette tells me that sleeping on top of your roofrack is a good idea and that makes sense to me - but watch your step when getting out of bed for a midnight pee). Avoid lying/sleeping on the ground outside at all times. People have died from bites of whatsit creatures that populate these areas and some even froze to death. Yea I know, you have heard and/or read all these tales of how nice it is to sleep in the open in the middle of nowhere, looking at the stars and more of that romantic bullshit. Famous last words: Don‘t worry, there are positively NO dangerous creatures in this area, I know it, I have slept outside here tens of times“. The definition of area“ is as precise as yonder“ or over there“. They were just lucky. Period.
The sand itself.
They say that the Inuit have like thirty or more words for different kinds of snow - and so must desert inhabitants have for sand. There are many kinds of this stuff, as you will find out for yourself when driving of digging in it. The driving itself is nothing special as long as you avoid speed in the first place. Looking at sand for a couple of hours may have much the same effect to you as what is sometimes called road hypnosis“, encountered on any civilized“ world freeway. At any given time you may find that your eyes are going out of focus and you don‘t see all that well anymore. This means that it is time to stop and take some rest or change drivers. Sand -and sand tracks for that matter- can be very treacherous, so good concentration is absolutely necessary because you want to see nucances of sand color on a sand color background. Compare this with a painting in white paint on a white canvas. This, combined with speed, can be suicidal / murderous.
Also, avoid roofracks at any time. Your Landy was not designed for carrying anything on its head. Leave that to the inhabitants of Oogaboogaland and moronic tourists.. A top-heavy Landy, driven on an inherently unstable surface like sand / sand tracks, may only need a light swerve to make it land on its side, faster than you can say Oh Sheeet“. By the way, like me writing this or not, the load limit - in height- of a Landy (or any other vehicle) is the top of the pick-up bed side boards. This will give you maximum stability. Loading a Landy, inside up to the roof, is as stupid as loading a roofrack. If you want more loading capacity than your pick-up bed, tow a (light !) trailer. The trailers that perform best are the military-type a ton trailers on 750/16 tires and do not load them higher than the sideboards !
Speed:
a short word about this. You got this nice“, straight-looking and even-surfaced sand track leading 2,000 miles through a desert, and you are alone on the track (traveling this sort of roads with one vehicle only is allready sheer stupidity in itself), so you get bored stiff after an hour or so and, automatically, you may put the hammer down a little bit more to make the ride a little less boring. This can easily lead you to near to 90 Kph, which is way too fast for sand with a usually overladen Series III and a yapping travel companion, who is getting as bored as you have been for the past 300 miles. If you are not driving with the needed concentration, the abovementioned slight swerve may occur quite suddenly and it does not take a lot to lay your Landy on its side in the sand, even at relatively slow speeds like 70-90 Kph. Just be aware of this.
NEVER drink and drive, you may spill some.
Of course, you may see something off the road that you deem worth of more dedicated attention, such as leaving the track and going to have a look at it from close. Doing so is basically ok, as long as you stick to a simple basic rule: just don‘t drive off the track (I said that before) and try getting there. If there is no road or track leading there, stop and recon on foot first for sand crust and soil stability in general. Do it bit by bit if needed: walk, come back, drive, and so on. This is much better than just leaving the track and getting stuck or hitting something. I know, I know, walking a mile on foot in scorching heat, dragging your feet through sand is not fun either, but I did not tell you to go there, did I ? Sand driving is also one of the easiest and fastest ways of getting in an abominable mood, especially when your travel companion needs constant entertainment or is putting you off your concentration by silly chit-chat and drawing your attention to beautiful“ landmarks while you are trying to keep your truck on the road. (Remember that ANYTHING can be hidden under the sand, track or off-road). This actually happened to me once, so I told him to stick to position and directions information - at gunpoint. It worked. thinking of long-stretch desert driving as work and your boss will keep you accountable for damage. The idea is to get there and to deliver your cargo with no or minimal damage. If you think of it as fun, go wrestle an alligator in Louisiana.
Sand recovery:
ground anchor & winch. Invariably, you will get stuck at least once and preferably in the most deserted, tree-less spot on your route and, of course, you are traveling with one vehicle only, so you are in for some lone winching exercise. DO NOT rely on luck for finding a suitable ground anchor, carry one. Having to bury your spare wheel for an anchor will only get your mood even worse and you may well bend the rim, pull the tire off and get nasty blisters on your hands while digging. So what ground anchor do you want ? Short of fabricating one yourself, purchase one that looks like a lightweight marine anchor with swiveling spades“, that will dig in itself. No point in trying to hammer a piece of firewood or a length of old steel pipe into the ground in the same heat that makes camels fall off their socks. These anchors will dig themselves in and, when you winch yourself close enough to the anchor, your winch will be able to pull it out of the sand in all but extreme cases of bad luck so no digging is required.
Da Driving.
I have seen some guys practicing sand driving the French way: le pied dedans, ça passe ou ça casse (Put your foot down, it goes through or it breaks), or the Dutch way: ogen dicht en gas! (Close your eyes and floor it). This invariably leads to trouble unless you are one of the top contestants in the professionals-with-unlimited-budgets sand driving joke called Paris-Dakar or the total-nutcase-race called the Baja California where I blew up my 460 Chevy engine just 6 miles short of the finish some years ago.
I am writing this because I think that I may contribute just a little bit to help beginners to stay alive in the sand farce some call a holiday“. Not that I care, really.
The thing to do first is NOT to listen to so-called experienced“ sand drivers, but to go slow and use just plain, agricultural common sense. I said go slow“ didn‘t I ? Yes, sloooooooow, you got it right. If you are planning a sand/desert trip with a schedule to meet or planning a just-in-time thing to catch a pre-booked plane, my humble advice is to stay at home, rent an adventure“ video and enjoy others acting totally stupid while enjoying your favourite drink.
But I guess you have to do it anyway, huh. Don‘t come to me complaining that I did not warn you.
Go easy with yer foot, wild accelerations don‘t get you anywhere and may just dig yourself in when the conditions are right, also keep your foot stable from unvoluntary movements by seeking some friction with your boot against the bulkhead side panel (RHD) or against the centre bulkhead console (LHD), this eases driving off by keeping your engine revs constant. Also, try to avoid braking and in some cases you just might want to coast to a stop because any braking effort and subsequent amplified friction may cause a sand wheel chock“ to develop just in front of your tires and may well prevent andy subsequent drive-off.
If the going gets rough in sand, i.e. that your engine is really pulling to get you through that soft spot, do not even think of changing gears, you will only lose momentum. Just keep the revs up and keep going, without any accelerator pedal hesitation (!), until you are on better soil again. Building up momentum with your vehicle before hitting da bad spot is as important as traction. Indeed, in many (most) cases, traction only keeps the momentum up instead of pulling“ you through. One of the tricks that will help you through most difficult situation is the correct gear choice - and you don‘t have much choice: it all depends a bit of how well you know your vehicle, but as a rule of thumb, with 750/16 tires, a 2a or diesel Series III wants 2nd low gear and a Stage One likes 3rd low. High gears, even first, usually don‘t work in da soft stuff and first low is totally useless in these situations.
Think momentum and that is what usually makes it work.
Diff locks:
the best I can come up with are Tratech and Detroit Locker automatics. Get a Tratech progressive-positive locking one in front and a Detroit locker in the back axle. Since these are automatic, you can as well forget about them but they will give you all the traction you can get when you need it. Cost is about US $ 1,000.--
Long trips and brakes. I do not know many people who renew their brakes before tackling a long or very long trip, they all assume My brakes are ok right now, so why would they not be ok in a month from now ? Good question, but I have seen some sand plugging exercises where I went through a set of brake shoes in 2 days, that was in Yemen and I was not on a holiday there. What we found is that driving through deep, soft, fine sand had caused substantial ingress of sand into the brake drums and had acted like very efficent sand paper, severely scoring the brake drums and making the linings almost disappear. I was in for a surprise when I got back on a stretch of hard track for a fast pull-out and had to try to stop for an obstacle. Guess what happened.Sand and glass. You all may have seen skilfully decorated glass panes that had some nice motif engraved into the glass by sandblasting. Ever seen a matte windscreen ? No ? Good. That may mean you either have never been in a real sandstorm or that you had your glass surfaces suitably covered at the time that someone switched da Big Fan on. In emergencies, get your can of grease out of your tool box and liberally smear all glass surfaces that you may use to see through. The grease will trap the sand and after it is all over all you need to do is to wipe it off.
Shock absorbers:
corrugated stretches may destroy your vehicle and shake all loose that is not welded, so you may think that your shock absorbers are not important at all, for they may be rattled to pieces like all the rest. So I made an quite coincidental discovery when driving on railway sleepers for 3.000 Km in Sibir: I had broken 6 spring leaves, but my shock absorbers still seemed to be working. Koni, of course. No, I do not own any Koni stock. If you are thinking of attempting anything of the kind, just contact this manufacturer via their website, tell them what vehicle you have and what type of corrugations you plan to use to give your travel companion the shake of his life. They will gladly advise you the appropriate type of shock absorber.
Windshield wipers: these are meant to wipe water of your windscreen, not sand, and when you use your winscreen wash / piss thingy, you may well be mixing that sand into a very effective grinding compound. When your windscreen gets too loaded with fine sand particles for comfortable view, just stop and wipe it off using a very soft brush or use an air jet if you have an on-board compressor.
