A series of three photos from an exercise at Lancelin, probably around 1989? A few of us went out in Mogs to practice going up and down sand dunes, which can be more difficult than it looks. You have to choose the right gear for the slope and size of the dune, and consider the "sinkiness" of the sand, then gun it at the dune, roar up the face and then ease off just before the top - just in case the drop off is really severe and you end up tipping the truck end over end as you go over the top.
The dunes at Lancelin are pretty huge, and a lot of vehicles couldn't make it up them. The Lancelin range is open to civilians a lot of the time (they usually close it when fast movers are dropping bombs around the place), and we spent half the two week exercise towing civilians out of bogs. The usual rate of pay for towing someone out was a six pack of beer, but a particularly nasty tow might rate half a carton. We got drunk a lot without spending a cent on alcohol.
One nasty bastard in a Range Rover was towed out, and then welshed on the deal, refusing the pay the beer tariff. So we drove down a narrow, boggy track in front of him, went through the worst part with him right behind us, then the driver jammed on the brakes and forced him to stop in a really deep bog. With no momentum, he had no hope of getting out. We left him in a worse place than what we pulled him out of. Hope that taught him a lesson.
The Unimog is a marvelous beast, with 8 gears forward and reverse. I'm sure one of these photos shows a Mog going backwards up a dune, probably in 5th gear. You simply flicked a switch and the gearbox went from forward mode to reverse mode - there was no "reverse" gear as we normally know it.
We pulled a Landcruiser out of a dune around here - he was in the fanciest model it's possible to buy, loaded with kids and grandparents and the like, and he was bogged halfway up a dune. He was digging the car out with a plastic shovel normally used by kids to build sand castles, with all the family sitting in the car watching him work. I would have walked out and left them there. I bet he took it back to the dealer and asked for his $70,000 back (about what a flash model cost back then - the 'Safari' I think it was).
It's a long, long way down to the bottom of that dune.
I think we had one person break some ribs around this time - they charged at a dune, but misjudged the point of attack, and dug the front end into a dune at 50km/h. That's like driving into a concrete block at that speed. They slammed into the steering wheel, and spent the next few days in hospital. I think the co-driver broke his nose on the console. People kill themselves doing this sort of thing.