Chapter VIII: Artillery Tactics (2)

All of these pieces fire both shell and shrapnel, and they will break up most of the field works that are likely to be constructed (it is ordinarily not practicable to construct in field a work which would resist their fire unless considerable time is available for preparation). The 3.8" howitzer having same weight as 3” gun is quite as mobile. The 4.7" howitzer is as mobile as the 3” gun when it has eight horses. With 6 horses it cannot move as rapidly. The 4.7" gun can move over roads and fields, maneuver and take positions exactly like 3” gun, but it cannot move as rapidly.

The organization, tactical uses and methods of fire control of this ordnance are similar to those of the 3" gun. Each battery has 4 pieces, but howitzer battalions have only 2 batteries.

This ordnance is to be regarded as intended for the same uses as the 3” gun and as supplementary thereto. It should not be used for tasks where the 3" gun would do as well, but should be used for targets beyond the range or destructive power of the 3” gun.

These pieces may be needed against troops who have had 24 hours or so to prepare a defensive position, as in this time they can throw up works which would protect them from the 3" gun fire.

These guns use indirect laying as a rule, but may also use direct laying, being in this respect like 3" gun. They should be placed back of the 3” gun and not assigned to living targets which can be reached by the 3" gun. They should generally be concealed, for this purpose they require a flash defilade of 20 ft. Behind a second ridge is a good place. A clearing in the woods is also good, provided an aiming point is available.

The position should afford good lines of approach and retreat and for ammunition supply. The limbers are usually posted farther to the rear than in the case of the 3" gun. There should always be an infantry escort for these pieces, and machine guns may also be so used.

Usually this heavy artillery will take only one position during an action, and it is therefore desirable that this position be carefully selected. Ample time must be allowed for reconnoitering a position and therefore a representative of the heavy artillery should be well forward during the march, for this purpose.

On account of the great ranges at which heavy artillery is usually employed, battalions are split up even less often than in the case of 3" guns.

TRAJECTORIES AND CONES OF DISPERSION FOR SHELL AND SHRAPNEL]

The shell fire of these pieces will destroy the materiel of a battery. The 4.7" gun can destroy battery materiel with great accuracy at ranges up to 5,000 yds. Thus they can often prevent hostile light artillery from coming into action at all.

Whereas a reverse slope of about 15 degrees affords some protection against 3" artillery, only very steep slopes, 50 degrees or more, afford complete protection against the shrapnel of the field howitzer. (Fig V.)

If at the opening of the attack the howitzers cannot find the hostile artillery they may fire at the infantry. Later in the attack if the defender runs his artillery forward for direct fire, he may then be subject to the fire of the attacker’s heavy artillery.

Auxiliary observing stations from which target can be seen are of great importance, and as little can be seen from a range of 8,000 yds., it is necessary to have an observing station well to the front. Usually the artillery (bn.) commander himself will occupy a station from which the target can be seen. These stations are connected with the battery by the telephone equipment, which is ample. Sweeping fire is not used with these pieces, as it is too wasteful of the ammunition which is heavy and expensive. Fire only at what can be seen, or otherwise accurately located.

In defense these pieces are very useful in compelling the attacker to deploy early, or to make a very long detour to get out of their range if he turns the position.

_On the March._ As the 3.8“ howitzer and the 4.7” howitzer when provided with 8 horses, are very mobile there is no serious objection to having them well up at the head of the column except for the road space they occupy. Therefore if the tactical situation is such as to make it desirable to have these pieces well to the front they may be placed there. They would seldom, however, be attached to the advance guard. The 6" howitzer and 4.7” gun (and usually also the 3.8“ and 4.7” howitzers) should be placed immediately in rear of the last infantry organization in the main body (just ahead of the artillery combat trains). The possible necessity of having to strengthen the bridges for this heavy ordnance is an argument in favor of leaving them in the rear, as this necessity would delay the march of the infantry if the guns were in front. Ordinarily there is not as much speed required in placing this ordnance in action as is usual with the lighter pieces. Positions are selected with more deliberation.

Motor cars are extensively used for the transportation of field and siege artillery of all types from the lightest to the heaviest. Machine guns and some of the lighter types of rapid fire guns, including anti-aircraft guns, are often mounted directly upon the truck. The heavier pieces are hauled as trailers by the motor trucks, which serve also to carry ammunition and supplies. The mobility of the automobile motive power is greater than that of animals and the machine is less vulnerable to fire. The possibilities of motor operated vehicles in conducting artillery off the roads have not yet been fully demonstrated, but the conduct of the “quads” or 4-wheel drive cars is very satisfactory.

MOUNTAIN ARTILLERY.

There are many instances in campaign where the lack of roads or trails prohibits or unduly restricts the employment of light artillery. To meet such conditions, the mountain gun transported on pack animals has been constructed. The gun should, in principle, be as effective a weapon as the field gun but transportation conditions limit its practicable size and power.

The various patterns of mountain guns are distributed in 3- 4- and 5-mule loads. The weight that can be borne by the best pack mules, for other than brief periods, is limited to about 250 lbs. in addition to the weight of the saddle. As a gun of acceptable power can hardly be built within this weight, most mountain guns are made in two or more parts, each constituting the load of a mule. The piece is equipped with wheels and drag ropes for moving short distances without packing.

The weight of projectile fired from mountain artillery is approximately the same as that from 3" field guns but the muzzle velocity is considerably less and the range therefore shorter. The guns have a larger allowable angle of elevation than 3” guns (usually to 27° or 30°); they are in effect howitzers.

The general construction of the gun, carriage and ammunition is largely similar to those of light artillery. The gun is not permanently connected to the recoil mechanism on account of the division into mule loads but is dropped into recessed blocks on a sleigh when assembled for action; and there it is secured by a key. The sleigh forms the cover of the cradle and slides on the cradle guides in recoil. The trail is made folding and is adapted for firing in cramped positions. The guns fire fixed ammunition, shell and shrapnel. Mountain batteries have no limbers or wagons. The battery is provided with an ammunition train which may consist entirely of pack transportation or may include some carts or light wagons. The gun can be unpacked and ready to fire in one minute.

In the American service, a mountain battery consists of four guns and their accessories. It is divided into six sections and has in addition an ammunition train and a supply train. The first, second, third, and fourth sections are gun sections to each of which is attached a mule with pioneer tools. The gun section consists of a gun squad of 10 men together with a gun team of 4 mules with drivers and an ammunition team of the same strength. The 5th and 6th sections are ammunition sections with 6 mules in each team.

The ammunition train comprises ammunition mules and the mules carrying the forge, stores, tools, etc. The supply train carries kits, rations, forage, etc.

Though mountain artillery is the only form of artillery that can be used in country where wheel traffic is impossible, its use is by no means limited to such terrain. For assisting the attacking infantry throughout all stages of combat, it is very effective. The mule can go practically anywhere that man can, except where the latter resorts to climbing; hence mountain batteries are peculiarly effective in country that restricts the scope of light artillery. These guns require virtually no more cover for concealment on the march than do infantry and they are thereby able to effect movements on the battlefield, without attracting hostile attention or fire, that would be impossible with light arty. They are very useful in the defense of woods, in temporary forward positions, in rear guard actions or in general where their mobility and easy concealment have special application.

On equal terms, they are no match for light artillery, but in terrain that hinders the use of that weapon, the mountain gun is capable of a usefulness that increases with the restrictions imposed on the former.

ANTI AIRCRAFT ARTILLERY.

The introduction of air craft into warfare has naturally resulted in the use of special means of protection against this new menace. Probably the most effective method is attack by a superior number of similar craft on the principle of the cavalry screen.

Anti aircraft weapons include small arms, machine guns, and field pieces having a range and power approximating that of the lighter types of field artillery. Small arms are regarded as of little use in the attack of air craft. The field gun type, using shrapnel and high explosive shell appears to be the most effective. One German type has a calibre of 104 mm. and throws a projectile weighing 34 lbs. It has a maximum rate of fire of 15 shots per minute and a range (in height) of 12,500 ft. For some types of gun hits are claimed at altitudes of 10,000 ft. or more. Such performances must be regarded as most exceptional and their probability will not be great enough to force aeroplanes to remain at such altitudes. A lower elevation is necessary for effective reconnaissance and the aeronauts must of necessity frequently take the risk involved. Swift aeroplanes will be practically immune from anti aircraft fire at altitudes of 10,000 ft. or more. They will have a fair chance of escape as low as 5,000 ft. As the altitude is reduced below this figure the risk will very rapidly increase. Observation at heights of about a mile will, however, be frequently attempted, but efficient guns in sufficient numbers should be able to exact a heavy toll in the event of systematic efforts to observe at less elevations. Airships, because of their greater size, and slower and more regular movements, must remain at greater elevations to escape the effects of hostile fire.

The greatest difficulties encountered in anti aircraft firing are estimating the range and hitting a rapidly moving object. Results must be obtained by great rapidity of fire.

Thus, unless the burst happens to be directly in line with the target, it is impracticable to determine by observation from the firing point whether the shot is over or short.

Guns cannot fire vertically. Their elevation never exceeds 60° and in general 50° is the practicable limit. Beyond these angles accordingly the aircraft are immune.

New problems in exterior ballistics are introduced. The influence of air currents on the trajectory is considerable. Tracer shells which emit a smoke flame are occasionally used to verify the aim.

As the aeroplane may use any line of approach at will and moves at great speed, the need for a large number of very mobile, quick firing guns will be apparent. The guns are frequently mounted on motor trucks when used in the field.

Except for possible use in fortifications, special guns cannot evidently always be provided in sufficient numbers for this purpose. Arrangements must, therefore, be made for utilizing the standard field and siege guns and howitzers. This is usually accomplished by providing special types of mounts such as the split trail carriage, or by extemporizing means whereby the trail can be sunk in the ground to an extraordinary degree and the gun then prevented from overturning, by cables to holdfasts, etc.

The anti aircraft gun may be considered to have satisfactorily fulfilled its function if it prevents aircraft from flying at altitudes sufficiently low to permit effective reconnaissance.

REMARKS CONCERNING THE TACTICAL EMPLOYMENT OF LIGHT FIELD ARTILLERY.

The following principles are of general (but not universal) application in the tactics of field artillery. They may be considered as useful suggestions, to be varied, however, as circumstances may dictate.

A battalion of artillery should seldom be sub-divided. A battery of artillery has but one range finding equipment. Its subdivision would be justified only by most unusual conditions.

At the opening of an engagement some of the artillery may, according to circumstances, be held “in observation,” or “in readiness,” exceptionally in a small force, more frequently in a large one.

It having been decided to place the artillery in action it should be brought to its position promptly.

The artillery and combat trains should, when practicable, be conducted to their positions by concealed routes. Utilize the roads as far as practicable, avoiding long movements across country. Concealment in position and en route thereto and good observing stations are the principal technical requirements of an artillery position. The position should be concealed from the enemy’s observation from either front or flank. The position should be sufficiently roomy for the unit which occupies it. It is not desirable to crowd guns at less than their proper interval (20 yds.), but it often is necessary.

A good position for artillery in attack may often be found between the holding and enveloping attack. In either attack or defense a favorable position may be found on the flank. If the artillery is thus exposed it will usually require a guard or escort of other troops (to be designated by the supreme commander, often from the advance guard) both in position and en route thereto. The artillery in any case should have out the necessary details for protection and observation of fire.

If there be a choice between two crests it will generally be better, when other considerations are not paramount, to select the one farther from the enemy.

If direct fire is contemplated at any stage of the action the position should be selected with a view to this. Such a provision would be more usual in defense than in attack.

Flash defilade requires 12 to 15 ft. of vertical cover. In solving defilade and other visibility problems allowance should be made for the vegetation.

It is ordinarily desirable to obtain a range between 2,500 and 3,500 yards from the probable target. Initial range in defense may be somewhat greater than in attack, since the hostile infantry will approach the position.

It is desirable to secure at the outset a position suitable for all stages of the action. Artillery once committed to action should not be moved during the course of the engagement unless it is apparent that a distinct advantage may thereby be gained, or unless such a movement is unavoidable.

The front may be covered and dead spaces eliminated by a subdivision and distribution of the artillery units.

Covered approach and concealment in position are desirable for the combat trains. Unless otherwise specially ordered the combat trains will be at the disposal of the artillery commander. In some cases they may take their stations under cover of the artillery fire.

The artillery prior to and during the action reconnoiters the terrain with a view to the selection of artillery positions. This is done without special orders. An artillery officer with the necessary reconnaissance detail should be with the advance guard during the march for this purpose.

The B. C. station should be close to the battery, and not in a conspicuous position, likely to draw the enemy’s fire.

Shrapnel should be used against living targets and for ranging. Shell is used against material objects. A hostile battery which has been immobilized by shrapnel fire may be destroyed by shell fire.

In ranging the first bracket should be of ample span, 400 yards is generally a good distance.

A duel between the opposing artilleries is not a necessary preliminary to every combat. It is the duty of the artillery in both attack and defense to support the infantry. It should therefore direct its fire as a rule, upon that element of the enemy which is at the time or may become the most threatening to the friendly infantry. Firing over the heads of the infantry will be the rule, in both attack and defense. The attacker’s artillery, having once opened fire upon the infantry firing line of the defense, should ordinarily continue this fire until the proximity of the assaulting infantry to the position makes it necessary to increase the range.

There should always be the closest co-operation between the artillery and the other arms. The artillery commander during the engagement will often be with the supreme commander. If not he should be in close communication with him, generally through an artillery agent.

With rare exceptions the artillery in both attack and defense will be in rear of the general line of battle of the infantry. It may be stated as a very rough guide that the artillery of the defense will be, in the average case, approximately 500 yds. in rear of the infantry firing line, particularly when indirect fire is employed. The mission of the force, the nature of the terrain and the conditions of the case will determine the position of the artillery, which may also be subject to change during the action. In case of a counter-attack, pursuit, or occupation of a captured position, the artillery may often be pushed boldly to the front.

Instructions too much in detail should not be given to artillery in orders. It is usually unnecessary in the ordinary case for the supreme commander to encroach upon the province of the artillery commander by directing him to (a) Fire on any specified target, (b) Obtain firing data, (c) Reconnoiter advanced positions, (d) Take station at a definite point, (e) Open fire at any specified time. He should, according to circumstances, be directed ordinarily merely to take position (1) for immediate action, (2) in observation, or (3) in readiness. The information in the order as to the enemy and his own troops indicates to him what the probable targets will be and when and where they will probably appear. This information, together with the rule to fire on the hostile element most dangerous to the friendly infantry, enables the artillery to obtain the necessary firing data and fire on the proper target, (a) and (b). As to (c) the artillery commander will, without orders, consider the possibility of occupying a new position, according to developments, and he will conduct the necessary reconnaissance for this purpose, so as to be ready to move to a new position when later ordered to do so. As to (d) the supreme commander should, in his orders, direct the artillery to take position _near_ such a place, leaving the selection of the exact location for the artillery to its commander. As to (e) if posted for immediate action the artillery will open fire as soon as the target appears. In the other two cases it will not open until it receives additional orders. Case (2) in observation, is used when the supreme commander does not wish fire opened prematurely, although he has decided where to place the artillery. Case (3) in readiness, is characteristic of a position in readiness, where combat position of the artillery is not yet definitely decided upon. The supreme commander may, both prior to and during the engagement, consult the artillery commander, obtaining the latter’s views as to the positions for and handling of the artillery, and give him detailed instructions, but this should not appear in the orders. When using the expressions (1), (2) and (3) in orders, it is well (in solutions) to add after your order, an explanatory note as to why more definite instructions are not given to the artillery commander. In some cases it may be desirable to give the artillery more definite instructions in orders but such cases would not be usual, and could often be covered by a consultation, omitting detailed instructions from the orders. If detailed instructions, as to particular targets on which to fire, advanced positions, etc., are considered necessary in orders it is usually well to add (in your solution) a note explaining why such orders are considered necessary in this case. If firing data are to be obtained by “registration” (bracketing fire) the order may contain instructions to that effect. See also Chapters IV, V, VI, XI, XIII, XIV, XVII and XVIII.