Military

(1) Maintenance . Maintenance, particularly operator maintenance, is of major importance in motor movement in mountainous terrain. Before and during operations in the mountains, the safety devices of all vehicles must be thoroughly checked. On-the-spot adjustments must be made to ensure proper operation. Mechanical failures that might be considered of minor importance in other situations may cause serious accidents on steep grades and sharp curves. Proper inspection of the brake linkage and proper adjustment of brakes are critical. The emergency brake must be able to limit speed when descending steep slopes. The transmission must be properly maintained and in good operating condition.

(2) Planning considerations . Steep grades are prevalent in mountainous terrain. The proper selection of vehicles for an operation will enable continued movement without resorting to winching. Drivers must be extremely careful at all times because of sharp, blind curves and dangerous grades. Either uphill or downhill grades should be taken in a gear ratio that will enable the vehicle to take the entire hill without shifting. When entering a short, steep grade, the driver may build up momentum on the approach so that this added momentum will carry him over; or, he may drop into a lower gear to allow for a long steady pull with maximum traction. Use caution to ensure that the speed of the vehicle does not exceed the speed (listed on the chart in the cab of the vehicle) for that particular gear ratio.

During daylight operations, all vehicles will normally be in open column. Here, guard against bunching on the approaches to grades and curves. This is important because slow movement of columns in mountainous areas makes vehicles extremely vulnerable to enemy attack.

Blackout driving in mountains will often exceed the danger of enemy action. Therefore, driving without lights on narrow, winding mountainous roads should be held to a minimum. Blackout driving should be limited to those stretches of road subject to enemy observation. At these points, post signs and guides to give special instructions to each driver as he approaches. Trucks should be close-column for blackout operations. Descend hills with a combination of braking and engine power; neither should be used alone to bring a vehicle downhill.

(1) Mud and swamps . Swamps, bogs, and mud caused by the nearness of the water table to the top of the ground should be avoided by all traffic, if possible. The surface crust may appear dry and well covered with vegetation, but any breakthrough may result in the vehicle becoming hopelessly stuck. The depth of soft mud below the surface is extremely difficult to determine. The depth may vary in the same swamp from between 1 to 2 feet.

When it is necessary to cross such barriers, make provisions to bridge the surface by suitable reinforcement with mats, brush, or special flotation materials. By increasing flotation in this way and by avoiding concentrated loads, traffic may cross otherwise impassable barriers without undue loss or delay. If support of a tactical operation requires movement over large areas of marsh or swampland, help from engineer personnel and equipment must be available. Vehicles with maximum flotation must be selected.

(2) Ditches and streams . Drainage ditches and canals, gullies and ravines, and streams and rivers present obstacles to motor movement--especially if the obstacle is large and if the movement is open to enemy action. Map study, reconnaissance, and intelligence reports may supply all information necessary to planning personnel.

When there is doubt about the ease of crossing an obstacle, request an engineer reconnaissance. The engineers can determine what must be done to make the crossing. Small ditches, gullies, and streams will not cause serious delays, but, even here, approach and passage at reduced speeds require traffic control to avoid congestion. Canals, ravines, and rivers present serious obstacles to motor movement and require definite means for crossing.

Existing bridges and fords offer profitable targets for enemy artillery, bombing, sabotage, and guerrilla activities. Therefore, no movement should be made without a provision for changes in plans demanded by current intelligence.

Techniques of crossing, capabilities of vehicles, and requirements for the construction of temporary bridges or crossing expedients are covered in appropriate FMs and TMs. In general, the existence of canals, ravines, and rivers that cross a selected route requires added preparation by planners. Planners do this to--

• Avoid congestion in critical areas.
• Arrange for repair or construction at crossing sites.
• Furnish adequate instructions to operating personnel to ensure proper conduct of the operation.

See FM 20-22 for detailed information on vehicle recovery operations.

(1) Driving. . Due to the general absence of established roads in desert areas, desert driving calls for experience, individual skill, and physical endurance of the vehicle operator. Driver training should include as much off-road operation and night operation as possible. Driver training should be carried out under a variety of conditions similar to those found in a desert. This training should include orientation on land forms, soil, and climate using photographs, films, and discussions.

Driving in sand requires judgment in selecting proper gear ratios, determining suitable speeds, and choosing the best ground. The driver must recognize the limitations of his equipment, particularly the tendency of wheeled vehicles to dig in when forward momentum is lost. He must be able to employ proper recovery expedients immediately. Provisions should be made for added equipment on the vehicles or within a column. Added equipment will be needed for the rapid recovery of stuck vehicles.

Unit SOPs should be modified for desert operations. The SOP should include procedures necessary to keep the column moving without unnecessary congestion around a disabled or immobilized vehicle.

Driving in other desert land forms requires the application of a variety of driving principles. Driving in deserts demands sound judgment and experience on the part of both vehicle operators and command personnel. No simple formula or means of testing to determine soil trafficability in the desert has been developed. Therefore, each new situation must be evaluated in light of experience. In most desert areas, sand is the common obstacle.

(2) Maintenance. . Vehicular maintenance presents a major problem in all desert operations. Under the best conditions, movement of vehicles over desert terrain creates a great volume of dust. The dust factor alone demands constant unit-level maintenance to prevent abnormal wear and inoperable vehicles. Drivers must daily check and clean air filters (more often under extremely dusty conditions), check oil filters, and inspect steering knuckle boots for damage. Vehicle instruments should be sealed (using tape or sealing compound) to keep out dust. When servicing vehicles, care must be taken to ensure that no sand gets into fuel tanks and crankcases. Even with the best maintenance possible, wear will be greater in desert operations than in normal operations.

Excessive heat also creates maintenance problems. Overheating of vehicles, through long periods of operation in low gear and the rapid evaporation of coolants, requires more frequent rest periods to prevent or reduce engine damage. During these rest periods, vehicles should be faced into the wind to cool. During stops, be sure to inspect regularly the following--

• Fan belts, replacing immediately when excessive wear is noted.
• Radiators, to ensure free circulation of air and coolant.
• Batteries (daily), to maintain the proper level of electrolyte (water).

The combination of heat, sand, and rough ground in desert areas causes excessive wear to tires. The following guidelines will help drivers to maximize tire mileage:

• Maintain proper tire pressure to guard against rim slippage and broken tire fabric.
• With dual-wheeled vehicles, frequently inspect for stones wedged between the tires and remove them before damage is done to the side walls.
• When halted overnight or for any extended period, the rears of vehicles should be parked into the wind.
• Conduct night operations when possible to prolong tire life.

(3) March techniques. Motor movement operational techniques must be modified for desert operations. The desert usually has no well-defined roads or trails. Therefore, normal methods of assigning routes, direction by signs and guides, and movement control do not work. Movement from place to place is usually made using navigational methods and equipment. Take care to maintain sufficient dispersion to prevent presenting favorable targets to the enemy. Deserts generally offer little or no natural concealment from aerial observation. However, unevenness in terrain may afford cover and concealment from direct ground observation. Camouflage nets and shadows in broken ground areas must be used to give some measure of security.

(4) Planning considerations. Movement planning for desert operations involves looking at the influence of climate and terrain on movement. Planning personnel at all levels must be familiar with the capabilities and limitations of both personnel and equipment. Make necessary changes to the organization, training, and equipment as early as possible. Select vehicles most suitable for the local climate and terrain. This will ensure maximum mobility and will lessen excessive supply and evacuation requirements of the vehicles themselves. Selecting and/or training operational personnel is a major factor in planning. The physical and psychological effects of climate reduce personnel efficiency; at the same time, operational and maintenance demands are at peak levels. Selection of personnel should include only those best qualified physically and mentally to endure hardship.

Motor movement in desert areas is also made difficult by terrain and the tactical situation. Dispersion is increased to achieve some degree of tactical security. This increases the time length of convoys. Also, the experience with time and space schedules developed in other terrains will not be very helpful. Routing must be general rather than specific. This is because point-to-point distances may be materially increased by local nontrafficability. Column control is another problem. Column control will normally be exercised from within the column by radio or visual signals. Supply and evacuation movements in the desert usually involve greater distances. This is because of the dispersion of installations and the greater volume of supplies/support required in desert operations.

Training should stress leadership, physical conditioning, operation of vehicles in desert environment, and principles of land navigation. See FM 21-305 for details on desert driving.

(1) Driving. March control must be modified for jungle or forest operations. March units should usually move as compactly as possible to ease control, improve security measures, and aid rapid movement. Close column formations permit easier following of trail; however, in tactical situations, such formations increase the danger of ambush. Open columns and infiltration moves lessen the danger of a general ambush. However, the possibility for a small element or single vehicle being separated and ambushed is increased.

Base the desired formation on a careful evaluation of existing conditions. Always maintain close liaison between elements of the march. Avoid complete dependence on radio communication. Normal radio operating ranges are greatly reduced by dense vegetation and adverse operating conditions. In preparing movement orders or SOPs, be sure to arrange for alternate means of communication.

Reconnaissance must be provided both in advance of and during the movement. This is done to ensure adequate information on the selected route, provision of alternate routes, and timely warning of possible enemy interference. Reconnaissance units operating in these areas must be particularly well trained and alert. Maintain march discipline at all times and furnish adequate security at halts.

Aerial observation of ground movement is seriously restricted by overhead cover. By careful use of this overhead screen, large groups of vehicles may move or bivouac without danger of detection or attack from the air. Prescribed distances should be maintained at the cost of reduced speed.

(2) Maintenance . Motor maintenance is increased in jungles because of the added strains of operating on unimproved roads, long periods of operation in lower gears, and rust and corrosion caused by high humidity. Human efficiency drops sharply in tropical areas of high humidity, and efficient maintenance becomes extremely difficult.

(3) Planning considerations . Planning for movements in jungle or heavily forested areas requires early consideration of climate and terrain. Anticipate the need for added personnel and equipment to give timely support to movements. Distances involved may be comparatively short, but road speeds will usually be reduced. Allowances must also be made for route construction and maintenance. Supply and evacuation in jungle operations should be closely coordinated. The key is to make maximum use of trucks and to reduce traffic. Tropical conditions require increased protection for supplies against the effects of rain, high humidity, and heat from sunshine.

(1) Maintenance . In cold climates and during the winter months, motor maintenance becomes increasingly important and more difficult. Automotive equipment must be maintained in top mechanical condition to run efficiently in subzero weather. The conditions under which this maintenance must be performed are usually unfavorable. Seasonable preparation for cold weather is the most effective means of preventive maintenance. Inspect and winterize all vehicles before freezing temperatures are expected. Winterization includes--

• Lubrication. Lubricate vehicles thoroughly, using proper oil and grease for the expected temperatures as indicated in lubrication orders.
• Ignition. Clean spark plugs and adjust gaps. Check coil, generator, starter, voltage regulator, and distributor.
• Battery. Test cells, check electrolyte, clean terminals, and tighten cables and clamps. Battery efficiency drops in extreme cold when the heaviest output loads are required.
• Cooling system. Carefully inspect the cooling system for leaks, tighten connections, and replace worn hoses. Check the water pump, thermostat, and fan belt for proper operation. Drain and thoroughly flush the system and refill with the indicated solution of antifreeze.
• Fuel system. Check for fuel leaks and replace parts if necessary. Adjust the carburetor for cold weather operation. Check intakes and manifold gaskets. When extreme cold is expected, drain fuel tank sump to remove any water that may have accumulated and refill. Add 1 pint of Grade III denatured alcohol to every 10 gallons of gas to prevent freezing of fuel lines.
• Brakes. Check brake adjustment, fluid, linings, and connections.
• Exhaust. Check exhaust system for leaks. Carbon monoxide from a leaky exhaust system is deadly in a closed cab.
• Vision. Check lights, windshield wipers, mirrors, and defrosters.
• Tire chains. Make sure that tire chains are present, are the proper size, and are in good repair.

Driver duties and responsibilities in preventive maintenance are increased during cold weather operations. Each driver must be told that his comfort, safety, and perhaps his life, depend on preventive maintenance. Besides the normal before-, during-, and after-operation preventive maintenance, the driver must be careful to warm up his engine gradually before loading. He must be sure that the winterization of his vehicle is adequate and that it stays that way. He must know and apply the measures necessary to give him adequate vision in all kinds of winter weather. He must also be able to recognize the early symptoms of ignition failure or battery failure and take appropriate corrective action. Command supervision of maintenance activities in all categories is particularly important when heated facilities are inadequate or not available. Many times, only those items considered most important will receive attention from personnel whose discomfort is their major concern.

(2) Planning considerations . The successful planning and conduct of winter motor movements in the North Temperate Zone is based on thorough familiarity with local weather and terrain. Movement plans must take into account maximum severity of weather for the season and be flexible to allow for sudden changes. A sudden rise in temperature accompanied by a warm rain will turn trafficable snow into mud and slush. Temperatures, while above freezing, will cause great discomfort to personnel. Midwinter thaws are followed just as suddenly by subzero temperatures, causing the freezing of deep ruts and dangerous ice. The accumulation of frozen slush on running gears and the undercarriage of a vehicle may cause failure of components. Accumulation may also become of such a size as to bind moving parts and/or wheels and lead to accidents. Sudden changes in weather will often have a bad effect on motor transport operations. Advance planning and preparation must include--

• Winterizing vehicles to meet the most severe weather.
• Instructing operating personnel in winter hygiene and first aid.
• Issuing suitable cold weather clothing and equipment.
• Requesting engineer personnel and equipment as indicated to expedite movement.

Route selection should be based on data resulting from a route and area reconnaissance. Alternate routes should be used to take advantage of changes in trafficability due to weather. In spite of reduced speeds, column formations will normally be open due to the intervals required for increased stopping distances. During periods of low visibility, columns will close up to maintain control. Schedule frequent halts to allow drivers to rest and personnel to move about to improve circulation.