Infantry Drills

FM 3-21.8 – Chapter 8 – Section VII – Fighting and Survivability Positions

Section VII — FIGHTING AND SURVIVABILITY POSITIONS

8-143.  The defensive plan normally requires building fighting positions. Fighting positions protect Soldiers by providing cover from direct and indirect fires and by providing concealment through positioning and proper camouflage. Because the battlefield conditions confronting Infantrymen are never standard, there is no single standard fighting position design that fits all tactical situations.

8-144.  Soldiers prepare fighting positions even when there is little or no time before contact with the enemy is expected (Figure 8-16). They locate them behind whatever cover is available and where they can engage the enemy. The position should give frontal protection from direct fire while allowing fire to the front and oblique. Occupying a position quickly does not mean there is no digging. Soldiers can dig initial positions in only a few minutes. A fighting position just 18 inches deep will provide a significant amount of protection from direct fire and even fragmentation. All positions are built by stages. The initial fighting position construction can be improved over time to a more elaborate position.

Figure 8-16. Initial fighting position.

PRINCIPLES

8-145.  Leaders follow three basic principles to effectively and efficiently prepare fighting positions: site positions to best engage the enemy, prepare positions by stages, and inspect all positions. The leader’s responsibilities include the following:

– Protect troops.

– Plan and select fighting position sites.

– Supervise construction.

– Inspect periodically.

– Depending on assets, request technical advice from engineers as required.

– Improve and maintain unit survivability continuously.

– Determine if there is a need to build the overhead cover up or down.

Site Positions to Best Engage the Enemy

8-146.  The most important aspect of a fighting position is that it must be tactically well positioned. Leaders must be able to look at the terrain and quickly identify the best location for fighting positions. Good positions allow—

– Soldiers to engage the intended enemy element within their assigned sectors of fire.

– Soldiers to fire out to the maximum effective range of their weapons with maximum grazing fire and minimal dead space.

– Grenadiers to be placed in positions to cover dead space.

8-147.  Leaders must ensure fighting positions provide mutually supporting, interlocking fires. This allows them to cover the platoon’s sector from multiple positions. When possible, they site positions behind natural cover and in easily camouflaged locations. The enemy must not be able to identify the position until it is too late and he has been effectively engaged.

Prepare Positions by Stages

8-148.  Leaders must ensure their Soldiers understand when and how to prepare fighting positions based on the situation. Soldiers prepare fighting positions every time the platoon makes an extended halt. Half of the platoon digs in while the other half maintains security. Soldiers prepare positions in stages and a leader inspects the position at each stage before the Soldiers move to the next stage. When expecting an immediate enemy attack, Infantrymen dig stage 1 fighting positions. As time becomes available, these defensive positions are continually improved, enlarged, and strengthened.

Stage 1

8-149.  The platoon leader checks fields of fire from the prone position. For a stage 1 position (Figure
8-17) the Soldiers—

– Emplace sector stakes.

– Stake the primary sector.

– Position grazing fire log or sandbag between the sector stakes.

– Place the aiming stake(s) to allow limited visibility engagement of a specific target.

– Trace the outline of the position on the ground.

– Clear the fields of fire for both the primary and secondary sectors of fire.

– Ensure the leader inspects the position before they move to stage 2.

 

Figure 8-17. Stage 1, preparation of a fighting position.

Stage 2

8-150.  Soldiers prepare retaining walls (Figure 8-18) for the parapets. They ensure that—

– There is a minimum distance (equal to the width of one helmet) from the edge of the hole to the beginning of the front, flank, and rear cover.

– The cover to the front consists of sandbags (or logs), two to three high, and for a two-Soldier position, about the length of two M302 rifles (about 7 feet).

– The cover to the flanks is the same height, but only one M203 rifle length (about 3.5 feet).

– The cover to the rear is one sandbag high and one M203 long (about 3.5 feet).

– If logs are used, they must be held firmly in place with strong stakes.

– The leader inspects the retaining wall before they begin stage 3.

 

Figure 8-18. Stage 2, preparation of a fighting position.

Stage 3

8-151.  Soldiers dig the position and throw dirt forward of the parapet retaining walls and pack it down hard (Figure 8-19). They—

– Dig the position armpit (of the tallest Soldier) deep.

– Fill the parapets in order of front, flanks, and rear.

– Camouflage the parapets and the entire position.

– Dig grenade sumps and slope the floor toward them.

– Dig storage areas for two rucksacks into the rear wall if needed.

– Ensure the leader inspects the work.

 

Figure 8-19. Stage 3, preparation of a fighting position.

Stage 4

8-152.  In stage 4, Soldiers prepare the overhead cover (Figure 8-20). At times, the terrain will accommodate the construction of a position with overhead cover that protects Soldiers from indirect fire fragmentation while allowing them to return fire. Sometimes, especially on open terrain, this is not possible, and the entire position must be built below ground level. Although this type of position offers excellent protection and concealment to Soldiers, it limits their ability to return fire from within a protected area. To prepare overhead cover, Soldiers—

– Always provide solid lateral support. They build the support with 4- to 6-inch logs on top of each other running the full length of the front and rear cover.

– Place five or six logs 4 to 6 inches in diameter and two M203s long (about 7 feet) over the center of the position, resting them on the overhead cover support, not on the sandbags.

– Place waterproofing (plastic bags, ponchos) on top of these logs.

– Put a minimum of 18 inches of packed dirt or sandbags on top of the logs.

– Camouflage the overhead cover and the bottom of the position.

– Ensure the leader inspects the position.

 

Figure 8-20. Stage 4, preparation of a fighting position.

Inspect All Positions

8-153.  Leaders must ensure their Soldiers build fighting positions that are both effective and safe. An improperly sited position cannot be used and an improperly constructed position is a danger to its occupants. Leaders should inspect the progress of the fighting position at each stage in its preparation.

Fighting Position Materials

8-154.  Sometimes Soldiers must construct fighting positions using only the basic tools and materials they can carry or find in the local area such as entrenching tools, sandbags, and locally cut timber. At other times, significant amounts of Class IV construction materials and heavier digging tools may be available (Table 8-1).

Table 8-1. Examples of field-expedient fighting position materials.

Wall Revetment

·      Sheet metal

·      Corrugated sheet metal

·      Plastic sheeting

·      Plywood

·      Air mat panels

·      Air Force air load pallets

Stand Alone Positions

·      Prefabricated concrete catch basins

·      Military vans

·      Shipping containers

·      Large diameter pipe/culvert

·      Steel water tanks

·      Vehicle hulks

Overhead Cover Stringers

·      Single pickets

·      Double pickets

·      Railroad rails

·      “I” beams

·      2-inch diameter pipe

·      Timbers (2″x 4″, 4″x 4″, and larger)

·      Reinforced concrete beams

·      55-gallon drums cut in half

·      Culverts cut in half

·      Pre-cast concrete panels 6-8 inches thick

·      Airfield panels

Wall Construction (Building Up)

·      55-gallon drums filled with sand

·      Shipping boxes/packing material

·      Expended artillery shells filled with sand

·      Prefabricated concrete panels

·      Prefabricated concrete traffic barriers

·      Sand grid material

Aiming Stakes

·      2-foot pickets

·      Wooden tent poles

Limiting Stakes

·      2-foot pickets

·      Wooden tent poles

·      Filled sandbags

 

NOTE:  Regardless of the position design, the type of construction materials, the tools available, or the terrain, all fighting positions must incorporate sound engineering construction principles. Unless it is constructed properly, a fighting position can easily collapse and crush or bury the Soldiers within. FM 5-103, Survivability, and FM 5-34, Engineer Field Data, provide excellent information on these principles. Additionally, GTA 05-08-001, Survivability Positions, and GTA 07-06-001, Fighting Position Construction–Infantry Leader’s Reference Card, contain detailed information in easy-to-use formats.

TYPES OF FIGHTING POSITIONS

8-155.  There are many different types of fighting positions. The number of occupants; types of weapons; tools, materials, and time available; and terrain dictate the type of position.

8-156.  The do’s and don’ts of fighting position construction are listed in Table 8-2.

Table 8-2. Do’s and don’ts of fighting position construction.

DO…

DON’T…

·      Construct to standard.

·      Ensure adequate material is available.

·      Dig down as much as possible.

·      Maintain, repair, and improve positions continuously.

·      Inspect and test position safety daily, after heavy rain, and after receiving direct and indirect fire.

·      Revet walls in unstable and sandy soil.

·      Interlock sandbags for double wall construction and corners.

·      Check stabilization of wall bases.

·      Fill sandbags about 75% full.

·      Use common sense.

·      Use soil to fill sandbags, fill in any cavities in overhead cover, or spread to blend with surroundings.

·      Fail to supervise.

·      Use sandbags for structural support.

·      Put Soldiers in marginally safe positions.

·      Take short cuts.

·      Build above ground unless absolutely necessary.

·      Forget lateral bracing on stringers.

·      Forget to camouflage.

·      Drive vehicles within 6 feet of a fighting position.

8-157.  Infantry fighting positions are normally are constructed to hold one, two, or three Soldiers. There are special designs adapted for use by machine gun (M240B) and antiarmor (Javelin) teams.

One-Soldier Fighting Position

8-158.  Positions that contain a single Soldier are the least desirable, but they are useful in some situations. One-Soldier positions may be required to cover exceptionally wide frontages. They should never be positioned out of sight of adjacent positions. The one-Soldier fighting position (Figure 8-21) should allow the Soldier to fire to the front or to the oblique from behind frontal cover. Advantages and disadvantages to consider when choosing a one-Soldier fighting position include:

– The one-Soldier position allows choices in the use of cover.

– The hole only needs to be large enough for one Soldier and his gear.

– It does not have the security of a two-Soldier position.

 

Figure 8-21. One-soldier fighting position.

Two-Soldier Fighting Position

8-159.  A two-Soldier fighting position (Figure 8-22) is normally more effective than a one-Soldier fighting position. It can be used to provide mutual support to adjacent positions on both flanks and to cover dead space immediately in front of the position. One or both ends of the hole may extend around the sides of the frontal cover. Modifying a position in this way allows both Soldiers to have better observation and  greater fields of fire to the front. Also, during rest or eating periods, one Soldier can watch the entire sector while the other sleeps or eats. If they receive fire from their front, they can move back to gain the protection of the frontal cover. By moving about one meter, the Soldiers can continue to find and hit targets to the front during lulls in enemy fire. This type of position—

– Requires more digging.

– Is more difficult to camouflage.

– Provides a better target for enemy hand grenades.

 

Figure 8-22. Two-soldier fighting position.

Three-Soldier Fighting Position

8-160.  A three-Soldier position has several advantages. A leader can be in each position, making command and control easier. It supports continuous security operations better than other positions. One Soldier can provide security; one can do priority work; and one can rest, eat, or perform maintenance. This allows the priority of work to be completed more quickly than in a one- or two-Soldier position. This position allows the platoon to maintain combat power and security without shifting personnel or leaving positions unmanned. It provides 360-degree observation and fire, and is more difficult for the enemy to destroy because he must kill or suppress three Soldiers.

8-161.  When using three-Soldier positions, the leader must consider several things. Either the distance between positions must be increased, or the size of the squad’s sector must be reduced. The choice depends mainly on visibility and fields of fire. Because the squad leader is in a fighting position that will most likely be engaged during the battle, he cannot exert personal control over the other two positions. The squad leader controls the battle by—

– Communicating his plans and intent to his squad, including control measures and fire plans.

– Using prearranged signals like flares, whistles, or tracers.

– Positioning key weapons in his fighting position.

– Placing his fighting position so it covers key or decisive terrain.

– Placing his fighting position where his team might be able to act as a reserve.

8-162.  The three-Soldier emplacement is a T-position (Figure 8-23). This basic design can be changed by adding or deleting berms, changing the orientation of the T, or shifting the position of the third Soldier to form an L instead of a T. The layout of the position can be oriented to fire on expected enemy avenues of approach from any direction. Berms must not block observation or fire into assigned primary or alternate sectors. Care must be taken to properly support the overhead cover.

Figure 8-23. Three-soldier T-position.

Machine Gun Position

8-163.  The primary sector of fire is usually to the oblique so a machine gun can fire across the platoon’s front. The tripod is used on the side covering the primary sector of fire. The bipod legs are used on the side covering the secondary sector of fire. When changing from primary to secondary sectors, the gunner moves only the machine gun. Occasionally a sector of fire that allows firing directly to the front is assigned, but this can reduce the frontal cover for the crew when firing to the oblique (Figure 8-24). For a detailed discussion on the employment of the M240B, refer to Appendix A.

Figure 8-24. Machine gun position.

8-164.  After the platoon leader positions the machine gun, he marks the position of the tripod legs and the limits of his sectors of fire. The crew then traces the outline of the hole and the frontal cover (if it must be improved).

8-165.  The crew digs firing platforms first to lessen their exposure in case they must fire before completing the position. The platforms must not be so low that the gun cannot be traversed across its entire sector of fire, reducing the profile of the gunner when firing and reducing the frontal cover height.

8-166.  After digging the firing platforms, the crew digs the hole. They first place the dirt where frontal cover is needed, digging the hole deep enough (usually armpit deep) to protect them while allowing the gunner to fire with comfort. When the frontal cover is high enough and thick enough, the crew uses the rest of the dirt to build flank and rear cover. Trench-shaped grenade sumps are dug at various points so either Soldier can kick a grenade into one if needed. Overhead cover for a machine gun position is constructed following the steps of stage 4, preparation of a fighting position (see paragraph 8-152f and Figure 8-20).

 

NOTE:  In some positions, a machine gun might not have a secondary sector of fire. In this case, dig only half the position.

8-167.  For a three-Soldier crew for a machine gun, the ammunition bearer digs a one-Soldier fighting position to the flank that is connected with the gun position by a crawl trench. From this position, the ammunition bearer can see and fire to the front and to the oblique. Usually the ammunition bearer is on the same side as the FPL or PDF. This allows him to see and fire his rifle into the machine gun’s secondary sector and to see the gunner and assistant gunner.

Javelin Position

8-168.  The Javelin can be employed from initial or completed positions (Figure 8-25). However, some changes are required. For a detailed discussion on the employment of the Javelin, refer to Appendix B.

 

Figure 8-25. Javelin position.

8-169.  The gunner must keep the weapon at least 6 inches above the ground to allow room for the stabilizing fins to unfold. The hole is only waist deep to allow the gunner to move while tracking to acquire a target. Because the Javelin gunner must be above ground level, the frontal cover should be high enough to hide his head, and, if possible, the backblast of the Javelin. A hole is dug in front of the position for the bipod legs.

8-170.  When the Javelin can be fired in one direction only, the position is adjusted to provide cover and concealment from all other directions, and the Javelin should be fired to the oblique. This protects the position from frontal fire and allows engagement of the target from the flank. Both ends of the launcher must extend out over the edges of the hole.

8-171.  Overhead cover must be built on the flanks. Cover must be large enough for the gunner, the tracker, and the missiles. Overhead cover that allows fire from underneath can be built if the backblast area is clear. Overhead cover must be well camouflaged.

8-172.  The Javelin is an important weapon and is easy to detect. Therefore, selection and preparation of alternate positions have high priority. When preparing an alternate position, the gunner should select and improve a covered route to it so he can move to the position under fire.

SLM Position

8-173.  The AT4 can be fired from Infantry fighting positions. If the AT4 is to be fired from a two-Soldier position, the gunner must ensure the other Soldier is not in the backblast area. Assume the basic standing position, but instead of stepping forward, lean against the back wall of the fighting position. Ensure that the rear of the weapon extends beyond the rear of the fighting position.

 

NOTE:  Leaders must ensure that light antiarmor weapons are positioned so the backblast misses other fighting positions.

TRENCHES

8-174.  When there is time and help available, trenches should be dug to connect fighting positions so Soldiers can move by covered routes. The depth of a trench depends on the type of help and equipment available. Without engineer help, platoons dig crawl trenches (about 3 feet deep by 2 feet wide) (Figure 8-26). With engineer help, they dig standard trenches. The trench should zigzag so the enemy cannot fire down a long section. Platoons normally dig crawl trenches because engineer assets are usually limited. Platoons use crawl trenches to conceal their movement into and within positions. Spoil is placed on parapets, normally on each side of the trench. If the trench runs across a forward slope, all the spoil is placed on the enemy side to make the forward parapet higher. All spoil needs careful concealment from enemy direct observation.

Figure 8-26. Crawl trenches.


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