Infantry Drill Regulations, United States Army, 1911 Part 31

Artillery on the march or in action is ordinarily so placed as to be amply protected by the infantry. Infantry always protects artillery in its neighborhood.

580. The detail of a support is not necessary except when the artillery is separated from the main body or occupies a position in which its flanks are not protected.

The detail of a special support will be avoided whenever possible.

581. The formation of an artillery support depends upon circ.u.mstances.

On the march it may often be necessary to provide advance, flank, and rear protection. The country must be thoroughly reconnoitered by patrols within long rifle range.

582. In action, the formation and location of the support must be such as to gain and give timely information of the enemy's approach and to offer actual resistance to the enemy beyond effective rifle range of the artillery's flanks. It should not be close enough to the artillery to suffer from fire directed at the artillery. In most cases a position somewhat to the flank and rear best fulfills these conditions.

583. The support commander is charged only with the protection of the artillery. The tactical employment of each arm rests with its commander. The two should cooperate.

_INTRENCHMENTS._

(Plate V.)

584. Ordinarily, infantry intrenches itself whenever it is compelled to halt for a considerable time in the presence of the enemy.

Infantry charged with a resisting mission should intrench whenever there is any likelihood that the cover constructed will be of use.

585. Except in permanent fortifications or in fortifications prepared long in advance, the infantry plans and constructs the field works that it will occupy.

When performing their duties in this connection officers should bear in mind that profile and construction are simple matters compared with location and correct tactical use.

586. Intrenchments enable the commander to hold a position with the least possible number of men and to prolong his line or increase his reserve.

They are constructed with a view to giving cover which will diminish losses, but they must not be so built or placed as to interfere with the free use of the rifle. Fire effect is the first consideration.

587. The trace of a fire trench or of a system of fire trenches depends upon the ground and the proposed density of the entire firing line. The trenches are laid out in company lengths, if possible.

Adjoining trenches should afford each other mutual support. The flanks and important gaps in the line should be protected by fire trenches echeloned in rear. (Fig. 6).

588. To locate the trace, lie on the ground at intervals and select the best field of fire consistent with the requirements of the situation.

A profile should be selected which will permit the fire to sweep the foreground, require the minimum of labor and time, and permit the best concealment. No fixed type can be prescribed. The type must be selected with due regard to the terrain, the enemy, time, tools, materials, soil, etc.

589. _Hasty cover._ With the intrenching tool, troops can quickly throw up a low parapet about 3 feet thick which will furnish considerable cover against rifle fire, but scarcely any against shrapnel. Such cover is frequently of value to an attack that is temporarily unable to continue. In time, and particularly at night, it may be developed into a deep fire or cover trench.

590. _Fire trenches_ should be placed and constructed so as to give a good field of fire and to give the troops protection behind a vertical wall, preferably with some head or overhead cover. They should be concealed or inconspicuous in order to avoid artillery fire or to decrease its accuracy. They should have natural or artificial communication with their supports, but in establishing the trace this is a secondary consideration.

The simplest form of fire trench is deep and narrow and has a flat, concealed parapet. (Fig. 1.) In ordinary soil, and on a basis of two reliefs and tasks of 5 feet, it can be constructed in about two hours with intrenching tools.

This trench affords fair cover for troops subjected to fire, but not actually firing. When it is probable that time will permit elaboration, the simple trench should be planned with a view to developing it ultimately into a more complete form. (Figs. 2 and 3.) Devices should be added to increase the security of the trench and the comfort of the men.

Where the excavated earth is easily removed, a fire trench without parapet may be the one best suited to the soil and other conditions affecting the choice of profile. (Fig. 4.) The enemy's infantry, as well as his artillery, will generally have great difficulty in seeing this type of trench.

In very difficult soil, if the time is short, it may be necessary to dig a wider, shallower trench with a higher parapet.

[Ill.u.s.tration: Plate V.]

Head cover, notches, and loop holes are of value to troops when firing, but many forms weaken and disclose the location of the parapet. Filled sandbags kept in the trench when the men are not firing may be thrown on the parapet to form notches or loopholes when the troops in the trench open fire and concealment of the trench is no longer necessary or possible.

By the use of observation stations the maximum rest and security is afforded the troops. Stations are best located in the angles of traverses or at the end of the trench.

591. Where the nature of the position makes it advisable to construct traverses at regular intervals it is generally best to construct a section of trench for each squad, with traverses between squads. (Fig.

5.)

592. _Cover trenches_ are placed as closely as practicable to their respective fire trenches. Where natural cover is not available, each fire trench should have artificial cover in rear for its support--either a cover trench of its own or one in common with an adjoining fire trench.

The cover trench is simple and rectangular in profile. Concealment is indispensable. It is generally concealed by the contour of the ground or by natural features, but to guard against hostile searching fire overhead cover is frequently advisable.

Cover trenches should be made as comfortable as possible. It will often be advisable to make them extensive enough to provide cooking and resting facilities for the garrisons of the corresponding fire trenches.

593. _Communicating trenches_ are frequently necessary in order to connect fire trenches with their corresponding cover trenches where natural, covered communication is impracticable. They are generally rectangular in profile, deep, and narrow. They are traversed or zigzagged to escape enfilade.

Returns or pockets should be provided for use as latrines, storerooms, dressing stations, pa.s.sing points for troops, etc.

Cover from observation while pa.s.sing through the trench may insure against loss as effectively as material cover from the enemy's fire.

_Communicating ways_, naturally or artificially screened from the enemy's view, sometimes provide sufficient cover for the pa.s.sage of troops.

594. _Dummy trenches_ frequently draw the enemy's attention and fire and thus protect the true fire trench.

Any type is suitable which presents to the enemy the appearance of a true trench imperfectly concealed.

595. When it is uncertain whether time will permit the completion of all the work planned, work should proceed with due regard to the order of importance of the several operations. Ordinarily the order of importance will be:

1. Clearing foreground to improve the field of fire and construction of fire trench.

2. Head or overhead cover; concealment.

3. Placing obstacles and recording ranges.

4. Cover trenches for supports and local reserves.

5. Communicating trenches.

6. Widening and deepening of trenches; interior conveniences.

See paragraph 568.

_MINOR WARFARE._

596. Minor warfare embraces both regular and irregular operations.

Regular operations consist of minor actions involving small bodies of trained and organized troops on both sides.