Manual for Noncommissioned Officers and Privates of Infantry of the Army of the United States, 1917 / To be used by Engineer companies (dismounted) and Coast Artillery companies for Infantry instruction and training

by United States. War Department

Section 7. Outposts.

Troops not on the march provide for their security by outposts. The general duties of an outpost are reconnoissance, observation, and resistance.

The specific duties are:

1. To protect the main body, so that the troops may rest undisturbed.

2. In case of attack, to check the enemy long enough to enable the main body to make the necessary dispositions.

During an advance the outposts are usually detailed from the advance guard. During the retreat the outpost for the night usually forms the rear guard the next day. If the command remains in bivouac, the new outpost generally goes on duty at daybreak.

The vigilance of outpost troops must be unceasing, but they should avoid bringing on combats or unnecessarily alarming the command. Firing disturbs the rest of troops and, if frequently indulged in, ceases to be a warning.

No trumpet signals except "to arms" or "to horse" are sounded, and all unnecessary noises must be avoided.

As a rule an outpost will not exceed one-sixth the strength of a command. For a single company a few sentinels and patrols will suffice; for a larger command a more elaborate system must be devised. The troops composing the outpost are generally divided into a reserve and several supports.

At a proper distance in front of the camp of the main body a line which offers a good defensive position is selected. This is called the line of resistance, and should he so located that an advancing enemy will be held in check beyond effective rifle range in case of a small force, artillery range in case of a large force, of the main body until the latter can deploy. The reserve is stationed at some point in rear of this line, where it can be moved quickly to reinforce any point as needed. The line of resistance is divided into sections, the limits of each of which are clearly defined. A support is assigned to each section, which are numbered from right to left, and occupies a position on or near the line, having special regard to covering avenues of approach. The position occupied should always be intrenched. The reserve and supports proceed to their respective positions by the shortest routes, providing for their own protection by sending out covering detachments.

Generally speaking, about one-half the Infantry of the advance guard should be in the supports. As each support arrives at its position it sends out observation groups, varying in size from four men to a platoon, to watch the country in the direction of the enemy. These groups are called outguards. For convenience they are classified as pickets, sentry squads, and cossack posts, and should be sufficient in number to cover the front of the section occupied by the support and connect with the neighboring supports.

A picket is a group consisting of two or more squads, ordinarily not exceeding half a company, posted in the line of outposts to cover a given sector. It furnishes patrols and one or more sentinels, sentry squads, or cossack posts for observation. Pickets are placed at the more important points in the line of outguards, such as road forks. The strength of each depends upon the number of small groups required to observe properly its sector.

A sentry squad is a squad (eight men) posted in observation at an indicated point. It posts a double sentinel in observation, the remaining men resting near by and furnishing the reliefs of sentinels. In some cases it may be required to furnish a patrol.

A cossack post consists of four men. It is an observation group similar to a sentry squad, but employs a single sentinel.

As a rule not more than one-third of the support should be on outguard duty. As soon as they are sent out to their postions the support commander selects a defensive position on the line of resistance; gives instruction for intrenching same; establishes a sentinel to watch for and transmit signals from outguards; sends out patrols to reconnoiter the country to the front of his section and, if on the flank of the line, the flank; and then proceeds to make a careful reconnoissance of the section assigned him, rectifying the position of outguards if necessary, seeing that they understand their instructions in case of attack or when strangers approach their posts, and pointing out their lines of retreat in case they are compelled to fall back on the support.

When the outguards are established, the members of the support may stack arms and remove equipment except cartridge belts. No fires will be built or smoking permitted unless specially authorized, or no loud talking or other noise. All patrolling to the front will be done, as a rule, from the support. The support commander should locate the position of the adjacent supports und make arrangements with the commanders for the joint defense of the line of resistance. At nights all roads and trails should be carefully covered and the country to the front and between adjacent outguards well patrolled.

The line occupied by the outguards is called the line of observation. Outguards move to their positions providing for their own protection and so us to conceal the movement from the enemy. These positions are intrenched and are numbered from right to left in each support.

The duties of the outguard are to observe the enemy, to guard the outpost from surprise, and to make a preliminary resistance to the enemy's advance. The strength of the outguard will vary according to its object. When an important road which at night will afford a line of advance, or a bridge is to be covered, or when several posts are established from an outguard it should be of considerable strength, two squads or a platoon. When mere observation and alarm are all that is required four men will suffice. A squall is a good unit to use as an outguard; this will allow one double sentry post of three reliefs and one man in addition to the commander, who may be used for messenger service. The outguard should be carefully concealed.

The utmost quiet should be observed, and there should be no cooking or smoking. The intervals between outguards will depend upon the situation and the terrain. The line of observation is not necessarily continuous, but all avenues of approach must be carefully guarded. The distance of the outguard from the support likewise is governed by the terrain, but in general may be said to be from 300 to 400 yards. In thick country or at night outguards patrol along the line of observation between posts. Communication between outguards and the support is by signal and messenger, in special cases by wire. Members of the outguard retain possession of their weapons and do not remove their equipment.

Sentinels from the outguard are posted so as to avoid observation, but so that they may have a clear lookout and be able to see, if possible, by day, the sentinels of the adjacent outguards. Double sentinels are always posted near enough to each other to communicate easily in ordinary voice. Sentinels are generally on post two hours out of six. For every sentinel and every patrol there should be three reliefs, and outguards should be of a strength sufficient to allow this. The position of a sentinel should be selected with reference to observation. It may be advantageous to place a sentinel in a tree. Sentinels furnished by cossack posts or sentry squads are kept near their group. Those furnished by their pickets may be kept as far sa 100 yards away.

Reliefs, visiting patrols, and inspecting officers approach sentinels from the rear.

A sentinel on the line of observation should always have the following instructions: The names of villages, streams, and prominent features in sight and where the roads lead. The number (if any) of his post, and the number of his and of the adjoining outguards; the position of the support; the line of retreat to be followed if the outguard is compelled to fall back; the position of advance detachments and whether friendly patrols are operating in front; to watch to the front and flanks without intermission and devote special attention to unusual or suspicious occurrences; if he sees indications of the enemy, to at once notify his immediate superior; in case of imminent danger, or when an attack is made, to give the alarm by firing rapidly; by day to pass in or out officers, noncommissioned officers, and detachments recognized as part of the outposts, and officers known to have authority to do so; to detain all others and notify the outguard commander; at night, when persons approach his post, to come to a ready, halt them, and notify the outguard commander; the latter challenges, ascertains their identity, and acts accordingly. When individuals fail to halt, or otherwise disobey, to fire upon them after a second warning, or sooner if they attempt to attack or escape; to require deserters to lay down their arms, and remain until a patrol is sent out to bring them in; to order deserters pursued by the enemy to drop their arms and to give an alarm; if they fail to obey they are fired upon; to require bearers of flags of truce and their escorts to halt and to face outward; to permit them to hold no conversation and to see that they are then blindfolded and disposed of in accordance with instructions from the support commander; if they fall to obey to fire upon them; at night, to remain practically stationary, moving about for purposes of observation only; not to sit or lie down unless authorized to do so; in the daytime, to make use of natural or artificial cover and assume such positions as to give him the best field of view; to inform passing patrols of what he has seen; to carry his weapon habitually loaded and locked and at will.

Outpost patrols are divided into those which operate beyond the lines and those whose duty lies principally within the lines. The former, called reconnoitering patrols, scout in the direction of the enemy; the latter, called visiting patrols, maintain communication between the parts of the outpost and supervise the performance of duty on the line of observation. Reconnoissance should be continuous. Though scouts and detachments of cavalry remain in contact with the enemy, or at least push forward to a considerable distance, more detailed reconnoissance by infantry patrols in the foreground must not be neglected. Reconnoitering patrols are composed of at least two men and a skillful leader, who, in important cases, would be an officer. They obtain information, ascertain the presence of the enemy, or discover his approach. All patrols, when they cross the line of observation, inform the nearest sentinel of the direction in which they are to advance; on their return they similarly report what they have seen of the enemy; signals are agreed upon so that they can be recognized when returning. Any ground near the line of observation which might afford cover for troops, or for scouts or spies, and the approach to which can not be observed by sentinels, is searched frequently by patrols. Definite information concerning the enemy is reported at once. Patrols fire only in self-defense or to give the alarm. Supports on the flank of an outpost position patrol the country on the exposed flank. Visiting patrols and reliefs should not march in the open, and thereby expose the position of sentinels.

During a march in the vicinity of the enemy when halts are made, special measures for protection are taken. When the halt is for a short period, less than half an hour, the advance party and support remain at ease, the point and flankers move to positions from which they can obtain a good lookout, and additional patrols may be sent out from advance parties and supports. Where the halt is for a period exceeding half an hour a march outpost should be formed. With an advance guard consisting of a battalion, 2 companies in the reserve, 2 in the support, the latter having as advance party one-half a company, a typical march outpost would be formed as follows: The advance party would send one platoon, four or five hundred yards to the right as outguard No. 1, the remaining platoon constituting outguard No. 2. A platoon from the head of the support would be sent a similar distance to the left as outguard No. 3. The balance of the support would constitute the support of the march outpost, the reserve of the advance guard acting as reserve. On signal being given to resume the march, the various units would close in, and as soon as the advance party had assembled the march would be taken up.