Technology adapted for jungle warfare; jungle theatres provide some of the most challenging conditions for military operations anywhere on earth. Unlike the wide-open spaces of the hot deserts or the Arctic tundra, which offer their own challenges of extreme climatic conditions, the confines of the jungle hinder navigation and movement, forcing the soldier closer to nature than any other type of operation. (Ground Warfare).

Man can survive in the jungle by adapting to his surroundings, but without highly specialist equipment he cannot wage war, unless he turns to the blowpipe or bow and arrow of the few native human inhabitants of these regions. Logistics, navigation, weaponry and even the need to find pure water present problems for the modern jungle combatant.

Transporting the Troops

Rapid movement of military personnel in jungle regions is severely limited by both the dense foliage and the uneven terrain, with even helicopters being only of limited use. Suitable natural gaps in the canopy are scarce and it will almost certainly be necessary to clear a landing site by hand if aircraft are to land. Even assuming that an infantry patrol carries sufficient explosives to fell trees it may take several hours to level an area of sufficient size to allow even the smallest of transport helicopters to land safely. If only basic hand tools and manual labour are to be used for the clearance operation, the time needed can extend to a day or more.

Helicopter availability should never be taken for granted, even for peacetime casualty evacuation, as both rainstorms and visibility problems can almost be guaranteed to ground rotary wing aircraft when they are most needed. In wartime, it is unlikely that there will be sufficient helicopters available for all tasks requiring them, so ammunition resupply, mortar or artillery repositioning and casualty evacuation will take precedence over routine logistic resupply duties.

Where jungle roads exist, they will frequently be little more than narrow, badly rutted tracks in dry periods and near impassable quagmires in the rainy season. Only the most nimble of cargo trucks will be able to cope with the conditions and even light utility vehicles in the Land Rover/Cruiser class may fare badly.

The ubiquitous Unimog, from Mercedes-Benz, is one of the few dedicated military light cargo trucks that can cope with poor condition jungle tracks. Due to their high power-to-weight ratio, compact semi-forward control design, reputation for high reliability in all operating conditions and class-leading ground clearance, courtesy of a portal axle design, the Unimog medium-duty range (U1400/1600) can frequently transport cargo to locations that few vehicles in the 7.5-tonne class could possibly hope to reach. One of the greatest assets of the Unimog family, a feature which is especially useful in jungle driving conditions, is the synchromesh 8-speed manual gearbox that includes an integral transfer case which allows speeds down to 0.1 km/hr to be achieved, in either direction, yet gives a highway speed of 80 km/hr.

A smaller cargo truck which has also proven itself to be well-suited for use in jungle environments is the Austrian Pinzgauer, originally manufactured by Steyr-Puch but now totally constructed by Automotive Technik in England. Designed as a super-compact light/ medium utility vehicle for Alpine use, the high mobility Pinzgauer has an unusual torsion resistant central tube chassis that incorporates the transfer case and axle drives. Like the Unimog, the Pinzgauer has portal axles, though in this case they are of swing half-axle as opposed to the more conventional beam design. This near unique drive train configuration and the use of relatively large 8.25R16 tyres gives a ground clearance of 360 mm, which is about 50 per cent greater than most light or medium utility 4 x 4 vehicles.

In 4 x 4 soft top 716M form, the heliportable Pinzgauer has a gross vehicle weight (GVW) of just 3850 kg, but it can carry a payload of 1400 kg. The 6 x 6 version, which has a GVW of 4650 kg and permissible payload of 2000 kg, is in some ways even more capable for jungle use than the 4 x 4. With differentials locked on all axles and low range gearing selected, the six-cylinder inter-cooled, turbo-powered Pinzgauer can muscle its way through some of the toughest and muddiest terrain. Reliability of this compact military work-horse, which is only 1800 mm wide, is second to none.

The Swiss Army has replaced the Pinzgauer with the Bucher-Guyer Duro. Perhaps less charismatic than its predecessor, it has nevertheless recently been tested in Malaysia where a fair part of the countryside is constituted by jungle. The Duro is offered in both 4 x 4 and 6 x 6 guises.

In denser or more remote jungle environments where movement of personnel or cargo by even the most nimble of high mobility utility vehicles is hampered by a complete lack of easily widened roads or tracks, alternative methods of military transportation can become a logistical nightmare. The few natives of the region will usually limit their overland travel to narrow footpaths between settlements, preferring to use rivers as the main highways. In jungle regions where waterways provide the main lines of communication, those footpath tracks through the jungle which do exist are likely to make for difficult going due to the abundance of surface water, and in the wet season they will become virtually impassable if used by wheeled vehicles.

Amphibians, on the other hand, can provide a means of moving both personnel and cargo over comparatively long distances, albeit at relatively slow speed, by using a combination of water-ways and tracks. Boat-hulled multi-wheel vehicles such as the 6 x 6 Supacat from Alvis or pod-bodied tracked all-terrain vehicles such as the BV 206 from Hagglunds of Sweden and the Singapore Technologies Bronco, all offer a higher degree of jungle mobility than the average all-wheel drive light truck or utility vehicle.

The Supacat relies on low ground pressure tyres and permanent chain-driven six-wheel drive for mobility over soft ground, and being fully amphibious it can cross or navigate inland water-ways that would be a barrier to normal wheeled vehicles. Though it can propel itself through water by its wheels alone, a small outboard engine can increase its performance drastically. The combination of high power-to-weight ratio, good traction and unique hull shape also allows it to muscle its way through undergrowth, forging a path for following foot soldiers. Skid steering gives excellent manoeuvrability in close jungle and it can operate over types of terrain that would defeat most other load vehicles, including primary jungle which has sparse vegetation between tree trunks but is criss-crossed with ground roots.

The Hagglunds BV 206, although designed originally as an over-snow vehicle, has proven itself to be a highly versatile load carrier for jungle operating conditions. Consisting essentially of two tracked pods driven by an engine in the front compartment and linked by a unique universal jointed drive shaft arrangement, the BV206 is fully amphibious. Ground pressure exerted, even when fully laden, is less than half that of the human foot, due to its broad rubber track propulsion system, and it can tackle some of the wettest terrain with little drama.

The BV206 was designed to be amphibious from the outset, and can propel itself through water at four km/hr. Although not able to turn in its own length like the Supacat, as steering is effected by simply varying the angle between tractor and cargo pods, the BV 206 is still a very agile vehicle with superb articulation. The rear half of the vehicle is usually a dual-purpose light cargo or personnel pod, but cargo flatbed and mortar/weapons carrier platform units can be specified.

Sisu (formerly Patria Vehicles) has its version of an articulated tracked vehicle, the NA-series, but this was recently dropped from the Finnish firm's catalogue. This vacancy was recently filled by Singapore Technologies Kinetics with the Bronco, a somewhat larger vehicle. Formerly known as the ATTC, the Bronco has been ordered en masse by the Singaporean Army in various versions such as resupply, flatbed cargo, troop carrier (15, plus driver), ambulance and armoured engineer. It has a load capacity of five tonnes, but a footprint of 60 kpa. Its Caterpillar 350 hp engine enables it to cope with 60 per cent gradients. Amphibious, it relies on its tracks for propulsion at five kilometres per hour.

Finding the Way

Until the comparatively recent widespread availability of hand-held Global Positioning Systems, navigation in jungle areas relied on the traditional compass and regular plotting of the route covered. With terrain landmarks being few and far between, and invariably hidden by the vegetation, jungle movement is tediously slow. In most jungle environments, the use of sun and stars to calculate position is seldom possible due to the density of the canopy and mist overhead generated by the high humidity, so the patrol leader must be an accomplished navigator.

These days most aircraft, ships and main battle tanks are routinely fitted with GPS receivers, but although handheld units such as the PLGR-II family from Rockwell Collins have been in service for a number of years, it is still relatively unusual to find them on issue to infantry down at section or platoon level. Specially ruggedised for military use, with immersion protection and even a helmet-mounted antenna option, the second generation PLGR-II receiver is particularly well-suited for jungle use, though availability seldom matches demand. In a jungle combat theatre, where a company-sized battle group is usually regarded as being a large formation, it is imperative that GPS be available to at least the platoon commander, and possibly even his section leader subordinates, but this seldom happens in practice.

Over the last two or three years with the growth in the civilian sports and leisure market, the price of the latest generation hand-held GPS units from the major manufacturers has plummeted, and specifications have conversely soared. Today, the civilian user can achieve positional accuracy in three dimensions to as low as three metres (assuming that US DoD Selective Availability is not reactivated) yet price of these units is sufficiently low for most western soldiers to be able to purchase receivers for personal use. Similar in size to all but the smallest of mobile phones, these units are light and compact enough to slip into a combat vest pocket, but provide the infantryman with a navigational tool which, if regularly updated, will not only tell him exactly where he is or where he should be, but will also lead him to his final destination if pre-programmed.

Some say that GPS does not work under the jungle canopy, particularly if it is wet, but this appears to be an urban myth dating from the early days of the system when only a small number of satellites were in orbit. Today the network usually has 24 satellites in operation at any one time, and as many as eight can be `seen' from most points in the Tropics for much of the time. Even under the densest of double canopies, technological advances since the mid-nineties have led to lightweight units that should have little problem in receiving the minimum four signals required, though constant monsoon downpour conditions can cause problems. However, it must be borne in mind that even the hardiest of troops will be seeking shelter in monsoon conditions and would seldom be contemplating movement until the rains stop. According to expedition consultant Roger Crowhurst, who regularly leads parties across Borneo, the latest generation GPS receivers have never yet let him down.

Commercially available current generation hand-held GPS units are usually waterproof to an EC specification which demands immersion protection for thirty minutes at a depth of one metre. Once a unit has acclimated, so long as it is not taken into an air-conditioned vehicle, it should function normally in jungle humidity. It must be noted that some units are not sufficiently rugged for military use, though it is interesting to note just how much care the soldier takes with his privately purchased GPS, compared to the rest of his issued kit!

Thales Navigation of California, who produces the Magellan range of GPS units, now manufactures a range of third generation receivers which retail from under $240. Aimed at outdoor activists and adventure travellers, these units are both robust and state-of-the art. The Magellan Meridian series, which utilises quadrifilar antennas and twelve-channel parallel receivers to ensure excellent satellite tracking and fast position fixes even under heavy cover, is well suited for jungle environments. The unit even has rugged wraparound rubber `armour' for protection. It is also completely waterproof and floats, which are further advantages if used in the jungle.

It has been less than a decade since the GPS evolved from a vehicle-borne system to a mass-produced pocket-sized accessory, but latest advances in technology have now brought sizes down to such an extent that wristwatch-style models are now a reality. The E Trex Summit model from Garmin is currently being advertised as the world's smallest GPS, yet it offers the soldier even more information and uses than the bulky units carried in tanks and command vehicles during the 1991 Gulf War. Weighing only 150 grams, complete with two standard AA-size batteries, the E Trex has a potential battery life of sixteen hours in continuous use, though this can be extended considerably by switching the unit off when not needed.

All but the earliest of GPS receivers can also be used as an accurate navigation compass, and the latest wristwatch type lends itself well to this role in a military environment. In jungle, where the constant gloom makes accurately reading a conventional magnetic compass a difficult task, the backlight GPS screen can be a boon. The precision of the electronic compass is also greater. However, it must always be borne in mind that satellite transmissions could suddenly cease, especially in time of war or heightened tension, and so traditional back-up navigation aids should also be carried.

Seeing to Shoot

The high temperatures and excessive humidity found in equatorial jungle should not adversely affect most modern personal weapons, if the soldier is fastidious in his cleaning and maintenance routine. However, more time than usual may be required to perform these tasks due to the difficulty in keeping parts dry and clean in this environment. Low light levels may also cause problems if the individual is not fully competent at stripping and reassembling the weapon by touch alone.

Poor light under the dense canopy can also cause aiming problems as twilight vision `slows down' the eye. Most jungle engagements take place at very close range, and in these lighting conditions good peripheral vision to spot enemy movement is more useful than concentrated focusing ability. Reliance on iron sights, which allow maximum vision, rather than limited arc optical sights, makes practical sense, even though under firing range conditions the latter are more accurate. Theoretically, most optical sights are sealed units which should not be adversely affected by high humidity, but this does not mean that they cannot cloud over at just the wrong moment, and some users would even say that optics can almost be guaranteed to mist over just when most needed, which is another reason for using iron sights.

One alternative to optical sights which can be even more accurate in the hands of a skilled user, especially in close-quarter engagements like those to be expected in jungle theatres, is the laser aiming device. Not only do these weapon accessories give a faster sight picture in poor lighting, they also let the user fire a rifle accurately from waist level, thus cutting response time in a sudden confrontation.

Laser Devices, manufacturer of the widely used MR-2 aiming laser which can fit any Nato rifle capable of carrying a 1913 rail, not to mention the majority of the AK range of rifles, has recently released a compact visible and infrared spectrum unit which is claimed to be ideal for use in jungle environments. The Dual Beam Aiming Laser (Dbal) is waterproof to a depth of thirty metres, so is unaffected by jungle humidity. Powered by a single 1.5 Volt AA standard battery, it has a continuous activation life of approximately five hours. The Dbal can be used either with the naked eye or by operators wearing night vision devices.

Aimpoint, on the other hand, offers an interesting aiming device that does not allow to fire from the hip, but has the sometimes-useful feature of not emitting any laser beam. Based on diodes and waterproof to 25 metres, the Aimpoint operates on a clever dot alignment principle that allows aiming in the darkest environments.

Basic Survival

No matter how well equipped the jungle soldier is, without an adequate source of clean drinking water he will not remain efficient for very long. The body requires several litres of water per day to ensure it functions correctly, and death can occur in just a few days if one stops drinking in a hot environment. In the jungle, the soldier is nearly always surrounded by ready sources of water, and often he will be partially submerged in it, but very little surface or running water is likely to be pure enough for immediate consumption. Filtration bags and sterilisation tablets, assuming plenty are carried, should allow sufficient drinkable water to be produced, but the resulting liquid will probably not be aesthetically pleasing, will not taste particularly nice, and may well have a strong obnoxious odour. It will save a life, but is unlikely to be drunk in sufficient quantity as it looks, tastes and smells unpalatable.

An alternative to sterilisation tablets is the filter bottle, which the soldier can carry either in place of one of his issue bottles, or in addition to them. One such filter system is the Survivor 4i, produced by Thirstpoint in England. This advanced filter cap was designed to fit the British `58 Pattern water bottle, but can fit both military and civilian bottles with a similar sized neck thread. It uses a cartridge with a matrix of 2-micron holes to filter out waterborne pathogens such as Cryptosporidium and Giarda, plus a disinfection sleeve (Iodinator) to destroy common bacteria, such as E. Coli b, plus viruses like Polio type 1 and Herpes simplex.2.

To obtain clean and palatable water using the Survivor 4i, the soldier needs only to fill his water bottle from a jungle pool, or even a silt-laden stream or river, screw on the filter cap, agitate the bottle to release iodine into the water, and then leave for fifteen minutes. Once the required time has passed, the bottle can be gently squeezed to force clean water through the mouthpiece in the cap. The safe water can either be drunk straight from the bottle or transferred into a second, ordinary bottle for storage. A single filter cap should provide up to 350 litres of potable water before needing replacement. The system has been tested by the London School of Hygiene and Tropical Medicine and is endorsed by the Hospital for Tropical Diseases, London.

The jungle may be the most challenging of environments for the modern soldier, but with the right transport it should be possible to get him to the starting point of his foot patrol. He can be equipped with, or equip himself with, a navigation system suitable for use under the jungle canopy and his weapon can be fitted with a device to improve his aiming in close-quarter engagements in poor light conditions. Lastly, a small addition to his service water bottle in the shape of a filter, should allow him to source his own drinking water for the duration of his jungle patrol.