Moving on Sand - Dune Worlds: How Windblown Sand Shapes Planetary Landscapes - page 250

Fig. 22.6 Military dune buggies. These are Desert Patrol Vehicles
(DPVs) operated by the US Navy Seals, that permit high speed driving
in desert terrain for special operations. Note the low center of gravity,

the accessible spare tires, and communications. U.S. Navy photo
020413-N-5362A-013 by Photographer's Mate 1st Class Arlo Abra-
hamson Camp Doha, Kuwait (Feb. 13, 2002)

across the Sahara by Andre Citroen in December 1922. This
first motorized crossing took 21 days, using Citroen half
tracks ('autochenilles') to follow the camel tracks across the
Sahara desert from Algeria to Timbuktu on the banks of the
River Niger. This opened up a land connection between
North Africa and the isolated Sudan—the history of this
adventure, written by Ariane Audoin-Debreuil (the daughter
of a key member of the expedition) was recently translated
into English (Audoin-Debreuil and MacGill 2007).
The compromise design of a rear track to minimize the
ground loading and provide strong traction, with separate
steering at the front, is also found—for essentially the same
reasons—in the snow mobile or snow machine (Fig. 22.4 ).
These usually have only a single track for mechanical
simplicity, and of course skis rather than wheels at the front.
On hard icy terrain, the handling is much like a bike with
rather limited steering authority, but on deep, soft sand the

rear sinks down and the skis bite, and the feel becomes
almost like that of a speedboat.
As for wheeled vehicles, large tires to minimize ground
loading are the most obvious general modification. For
military operations, the British Long Range Desert Group
(LRDG, led by Bagnold in World War II) used conventional
trucks (Fig. 22.5 ): the main innovations were in the pro-
cedures and logistics such as the amount of water carried
and the use of sand channels. One addition was the use of a
sun compass to permit directional fixes to be made without
stopping (the ferrous metal content of the truck required one
to walk some distance away to make a reliable magnetic
direction determination).
Vehicles for recreational driving—thus usually more
energetic than Bagnold's trucks—on dunes are often called
'Dune Buggies' or 'Sand Rails'. The term 'buggy' derives
from the nickname of the Volkswagen Beetle or 'Bug', as