These Notes have been compiled from suggestions made by artillery and infantry Officers at the courses held at Aire. They are intended primarily for the use of Battery and Battalion Commanders belonging to new Divisions, who have not had previous experience of the present class of warfare.
(A.)CO-OPERATION OF INFANTRY AND ARTILLERY IN TRENCH WARFARE.
- Arrangements for Defence.A certain force of artillery is detailed for the support of each infantry brigade holding a portion of the line. Batteries are then allotted to each Sector. Arrangements are made to cover the front with rifle and machine-gun fire, and the places are selected where artillery fire is required. A code letter and number is given to each place on which guns are layed, and a sketch showing the code should be kept by the Company Commander in the trenches, by the Battalion Commander, at the O.P., and at the battery. A direct line is laid from company headquarters to the battery, tapped in at the O.P. and battalion headquarters, and the Company Commander provides the instrument and personnel at his end of the line. When fire is required at night on any particular point, it is sufficient to telephone down the code letter and number, and the gun concerned opens fire at once. Long discussions on the telephone as to the exact location of the target are thus avoided, and any correction can be made after the first round. If fire is required on any other place, it should be described with reference to one of the selected points. These points are usually referred to as the "night lines" of the battery.
When infantry reliefs take place, Battalion and Company Commanders should see a round or two fired the day before they come in, so that they may know where they can expect help.
- A Hostile Attack.Special arrangements must be made to meet a hostile attack by night, in a fog, or under cover of smoke and gas. Time is the essence of the problem, and it is more important to start guns firing at once than to wait for discussion on the telephone as to the exact position where the enemy has been first seen. Every gun should be normally layed on its "night line" when not otherwise engaged, and on receipt of a pre-arranged signal will open fire at once on this line, "sweeping" a certain amount where necessary. The Officer at the battery then endeavours to ascertain the situation, but if the wires have been cut, he must use his own discretion as to continuing fire.
An alarm signal is necessary, and the occasions on which it should be used must be clearly understood. Every precaution should be taken to prevent it spreading needlessly to neighbouring units.
It is advisable to test the alarm signal occasionally, but this must be done with caution. The Brigade or Division Commander, in consultation with the C.R.A., should alone be empowered to apply a test.
The telephone communications between the artillery and infantry should be tested frequently by day and night.
The infantry must clearly understand that, on receiving the alarm signal, the guns open fire on their pre-arranged "night lines," and that this signal is therefore only to be used while our infantry are in their present positions. If our infantry have captured a hostile trench and require artillery support at short notice, some other form of code should be used, as the use of the ordinary alarm signal in this case would lead to fire being directed on our own troops. V.V.V. followed by the name of the regiment requiring assistance is suggested as a suitable code when fire is required in front of a captured trench.
- Aggressive Action.In order to reap full benefit from aggressive artillery action, it is essential that, as on all other occasions, the infantry and artillery should co-operate closely in the work of destruction. We must use every means to entice the enemy from his dug-outs, and then catch him with 18-pr. shrapnel, machine-guns and rifle fire. Various methods are :
- To damage the enemy's front parapet with H.E. from howitzers and field guns, and cut his wire with 18-pr. shrapnel. He will then have to come out from behind cover to execute repairs, of which advantage should be taken by both artillery and infantry.
- Enfilade fire on communication trenches, especially at their junction with the main trench, and on front trenches at intervals both by day and night. Two or three rounds at a time, or a couple of battery salvoes, might easily do considerable damage, and are less likely to give away a battery at night. After the first few rounds the enemy will probably take cover, and further shooting is waste of ammunition. A single gun placed well forward to enfilade the enemy's front line trenches has been found very effective, and the flash can be entirely screened, except from the place at which it is shooting.
- Occasional rounds or salvoes of shrapnel as above, fired on cross roads, billets, or known headquarters especially at night on reliefs, ration parties, working parties, &c.
- Destruction of hostile observing stations, strong points, &c., with H.E.
- The enemy probably stands to arms as we do, at dusk and dawn. It is suggested that on given evenings and mornings, our infantry should be warned and all the field guns covering a brigade front should fire a couple of rounds of shrapnel per gun, at a pre-arranged signal, on the enemy's front trenches. After the first two salvoes he will probably take cover.
- Anything unusual which will make him look to see what is happening and have the effect of making him man his parapets, e.g., burning fires all along the British line at a given hour, red fuzees used in the same way, cheering or a groan along the line, cardboard figures all along the parapet, loud ringing bells, rapid bursts of infantry fire. In every case the artillery must be warned and two or three rounds of shrapnel per gun fired on a given signal. This will probably kill more Germans, and is a more effective means of "retaliation" than prolonged bursts of fire which are expensive in ammunition.
When the enemy's infantry are in their trenches, firing at one of our own aeroplanes, a suitable opportunity for artillery to open fire on their front or support trenches will probably present itself.
Shrapnel could also be usefully employed at a house burning in the enemy's lines, at points from which Very lights are usually fired, or at places where heavy rifle fire is heard.
When a portion of the enemy's line is being bombarded he often withdraws the garrison to either flank. A rapid switch might often inflict casualties.
Trench mortars should fire in co-operation with artillery when possible.
- Information.The artillery require all the assistance they can get as to the location of targets and the effect of their fire. Every endeavour should be made by the infantry to assist, and artillery observing stations should be connected to the front trenches and to divisional and artillery observation posts, for this purpose.
Young infantry Officers should be instructed in artillery methods of describing position of targets, and it is a great advantage to both branches of the service, if every infantry Officer in turn spends a few hours in the artillery observing station overlooking his part of the line. It helps him to know the country from an artillery point of view, knowledge which would be especially useful when the time came for an attack. In describing targets, reference should always be made to points in the enemy's line not to portions of our own line, and consequently all prominent objects in the enemy's line should be given the same name by both artillery and infantry.
A series of photographs are being taken from all artillery O.Ps. They will enable infantry and artillery Officers to study the ground together, and will be invaluable to battalions and batteries coming into the line of relief. Combined with a large issue of air-photographs, they will enable all officers to get a good idea of the ground over which they may have to advance.
- Position of Battery Commanders and Observing Officers.An Officer from each of these batteries must be at his O.P. while there is daylight, and an Officer or N.C.O. must always be on the look-out. During the present trench warfare a subaltern should normally perform this duty, and the battery commander reserve himself for special shoots; he should usually be employed in training his officers to direct and observe fire, and in keeping in touch with Battalion and Company Commanders. The personal element is of great importance in the co-operation of artillery and infantry.
By night an Officer of the battery must be in close touch with the battalion he is supporting. It depends upon circumstances whether he should be at his O.P. or at battalion headquarters, but in any case he must be in communication with the latter. See also B, para. 3.
(B.)CO-OPERATION BETWEEN ARTILLERY AND INFANTRY IN THE ATTACK.
- Plans for Attack.Should be made in consultation with the artillery, as the actual point selected for attack must depend largely on where artillery support can be most effective. It is especially necessary to consider where wire can be cut and where it is impossible on account of the configuration of the ground.
- Artillery Preparation.A series of bombardments and lifts over a wide front and lasting several days is a useful method of concealing the front selected for assault. The preliminary bombardment, which is to prepare the way for an attack, should vary in duration and intensity, so as to give the enemy no indication as to the actual moment of assault. A prolonged intensive bombardment with a sudden "lift" is a sure sign to the enemy that an assault is about to take place, especially if accompanied by heavy rifle fire from the flanks of the attacking troops. During the bombardment the infantry should creep as near to their objective as possible, and the assault should be delivered without any sort of "flourish of trumpets."
Trench mortars should take their part in the preliminary bombardment, and in helping to cut wire in certain places. Definite tasks should be allotted to them when the plans are being made.
- Position of Brigade and Battery Commanders.The Commander of the artillery Brigade or "Group" supporting an infantry brigade should be in close touch with the infantry brigadier, and if possible actually with him.
Battery Commanders must be where they can best see the general situation (usually their O.Ps.). Once the attack has been launched the situation changes so rapidly that there is often no time to receive orders from the rear, and battery commanders must be prepared to act instantaneously on their own initiative. It is not fair to shift the responsibility for the conduct of fire on to the shoulders of a junior Officer, and this applies to all batteries whether Field, Heavy or Siege.
- The Assault.Artillery fire must "lift" from the actual places to be assaulted, but H.E. from howitzers and field guns must be kept up on the immediate flanks of the attack. Field guns dug in near our front parapets are especially useful for this purpose and can also be used to make breeches in the hostile parapet just before the assault, and to knock out machine-gun emplacements both before and during the assault. These guns might subsequently be usefully employed for the close support of a battalion in its advance.
It is now the business of the artillery
- To keep down the fire of the hostile artillery. This is done by the counter-batteries.
- To prevent the enemy bringing up supports and reserves. For this purpose a steady fire must be kept up on his communication trenches, ditches, and other possible lines of approach, cross-roads in rear, and places where the enemy might mass for a counter-attack. The "box-barrage" is usually a waste of ammunition, but arrangements must be made to make a barrage at short notice in case the enemy decides to bring his troops up across the open.
The "lifts" want careful timing, and should be very gradual, of the nature of a creep, arranged to suit the pace at which the infantry are likely to make progress: it is often impossible, owing to dust, smoke, &c, to see exactly where the infantry have got to.
When smoke and gas are employed, the fire of the heavy artillery must be well lifted to avoid dispersing the gas.
- The Advance to the First Objective.To enable the infantry to make steady progress the continued support of artillery is required. A lull in the artillery fire usually occurs shortly after the assault has been delivered, owing to the difficulty of ascertaining how far our infantry have advanced, and what is stopping their further progress. Brigade and Division Headquarters have usually great difficulty in obtaining this information and in any case it generally reaches the battery commander too late to be of use. It therefore devolves on the latter to act on his own initiative, and he must place himself where he is best able to do this. He must keep touch with his battery and with the general situation, and for this reason it is seldom advisable for him to press on too far.
The battery commander must have another Officer known as the F.O.O.:
- To keep touch with the infantry commander whom he is supporting;
- To keep him informed as to the exact position of our infantry;
- To assist him in ranging on to anything that is checking the advance of our infantry.
This F.O.O. must be provided with telephone equipment and also with signalling screens, as the telephone wires will almost certainly be cut. In selecting his position he must remember:
- That his business is to assist his battery commandernot to join in the infantry fight.
- That his information is of no use unless he can get it back to his battery commander.
It will, therefore, seldom be advisable that he should be actually with a company or even a battalion commander in the front line, but he must keep the latter informed of his whereabouts, and be ready to visit him if required. The best position will usually be the farthest point forward to which good communication has been opened up, normally battalion headquarters. It will then devolve upon the infantry to let him know of their requirements, and here again it is most necessary that reports shall be intelligible to the artillery. Much of his information must be obtained from wounded officers or N.C.Os., and he must depend on his ears as much as his eyes.
Some form of light signal, which shall be visible to aircraft and the artillery through smoke and mist, is required to let everyone know when the infantry have gained a certain objective. It must be something that can be carried by every man, and small magnesium lights are suggested. They could be thrown back behind the objective, so as not to attract the attention of the enemy. Flags have been used but they generally get left behind, and are then very misleading.
Definite zones of action must be allotted to brigades and batteries. They must keep to their own zones and not be enticed by a tempting target to shoot on any other except under very exceptional circumstances. Otherwise several batteries may be ranging on to one target at the same time, and the difficulty of distinguishing their own rounds may lead to a total loss of effect.
- Advance of Artillery.
- When Artillery can advance in daylight. Guns must be pushed forward in support of the infantry, the advance being supported by fire from other field batteries and by the heavy artillery. In many places emplacements can be prepared beforehand near our original front line, but they must be carefully made and concealed. In any case a careful reconnaissance must be made beforehand and positions and observation stations allotted to batteries as far as this can be done. It may sometimes be possible to push up sections or single guns in support of the infantry when it would be impossible to send forward a complete battery, the section commander being placed under the orders of the commander of the battalion he is supporting.
The 4.5-inch howitzer is especially useful for the close support of the infantry, as it can be placed under cover in positions where the 18-pr. could not clear the crest. Armoured cars might also be usefully employed, for this purpose.
Excellent results can be obtained by combining the fire of 18-pr. and 4.5-inch howitzer batteries, the howitzers being used to bolt the enemy from cover, and the guns to shoot him when bolted.
- When artillery cannot move until dark.Often, however, the country will not allow of the guns being brought up until dark. It will then be necessary to dig in some guns beforehand, in or near our front line, and not allow them to be used until our infantry have reached their first objective.
In the case of a Corps attacking on a narrow front with two divisions in front line and one division in reserve, it would be a suitable arrangement to use the field artillery of the reserve division for this purpose. This latter division would then have the support of its own artillery for the attack of the enemy's second line, and would have it handy in case of a further advance.
(C.)SPECIAL TASKS OF THE ARTILLERY.
- Enfilade Fire.Great attention should be paid to this, both for attack and defence: batteries, sections, or single guns should be so placed as to get the maximum amount of enfilade fire to bear on the enemy's trenches, and on their communications.
The great advantages of it are often not fully appreciated. The flashes of guns can be concealed from observation except in the one direction, and the enemy cannot get an intersection on the flash. When firing against deep trenches, much better effect with shrapnel can be expected, and in the case of howitzers, it is much easier to obtain direct hits on the trenches.
It is noticeable that the enemy take every opportunity of bringing enfilade fire to bear; and in all the recent fighting those guns which opened fire were so placed.
It is often undesirable to place the guns of one division in the area of another division, and then this enfilade fire should be brought to bear by the batteries of a neighbouring division. This is arranged within the Corps, or if two Corps are concerned, is done by the Army, and the guns come under the command of the division whose front they are covering at the time.
- Wire-cutting.Good platforms and secure anchoring of guns are necessary to ensure accurate shooting, and guns must be overhauled by the artificer, and carefully calibrated beforehand. If the trail-eye is raised, or the wheels are lowered until the gun recoils along the trail, "side-slip" and "jump" are practically eliminated and much more accurate shooting is obtained. This also applies to guns run up to the front parapet to shoot at point blank range; the trail should then be raised till nearly horizontal.
It is now generally agreed that 18-pr. shrapnel is the most effective projectile, burst as close to the wire and as low down as possible. Experiments with H.E., whether burst on graze or with No. 100 delay action fuze, have given practically no effect against wire, but about 10 or 15 per cent. H.E. mixed with shrapnel is sometimes useful for dispersing the posts and the wire when cut. On hard ground percussion shrapnel is very effective.
The best ranges have been found to be from 1800 yards to 2400 yards, and five or six rounds per yard are then required for an entanglement ten yards deep. Wire can be cut up to about 3200 yards with a much larger expenditure of ammunition, but at longer ranges the 18-pr. gives little, if any, effect. In all cases close observation is essential, and it may sometimes be necessary to make special arrangements for this, e.g., by sapping forward and establishing O.Ps.
The 6-inch howitzer has been effectively employed against wire between 3000 and 5000 yards, and distant wire has been cut by 60-prs. firing H.E. with aerial observation.
Trench mortars should also take part in wire-cutting; the 2-inch is particularly useful.
Before artillery attempt to cut wire, infantry patrols should be sent out to report on the nature and extent of the wire, looking especially for low trip wires where the grass is long. They should also report on the progress of destruction. For distant wire this information can only be obtained from air photographs.
The following notes on German wire entanglements may be of use to our own infantry and R.E. :
- Iron posts are more difficult to destroy than wooden posts.
- Heavy coils of loose wire on iron posts or on broken ground are particularly difficult to destroy.
- The effect on trestle wire is easier to observe than on staked wire.
- Broken ground or a small bank in front of the wire greatly adds to the difficulty of cutting. Wire placed in a depression is similarly protected.
- A soft bank of earth behind the wire prevents it being swept away.
- Wire among bushes is hard to see, and it is difficult to tell if it is cut or not.
- Wire entirely hidden from view will seldom be cut.
- An irregular line with small salients is harder to range on than a straight line of wire.
- Bombardment of Trenches. Unobserved fire is useless and leads to waste of ammunition. Every round should be observed, either from an O.P. or by aeroplane. An exception must be made to this in the case of night firing to prevent the repair of wire and to prevent movements along the trenches and roads which have been carefully registered beforehand.
It should be explained to the men in the trenches that shrapnel to be effective must burst short of its target. When our front trenches are very close to those of the enemy they must expect the shrapnel to burst a very short distance in front of them. Similarly in a bombardment of the front trenches by howitzers, they should understand that the pattern made by a number of perfectly laid rounds is an elongated one, and that very little damage is being done to the enemy unless about 20 per cent, fall on our side of his parapet. When only a short distance separates the trenches the infantry must be cleared from our own front line if possible, as there is always the risk of an abnormally short round.
- Counter-battery work.To neutralise a hostile battery, a few rounds at a time, repeated at intervals, are more likely to stop it firing than a large number at one time. To destroy a battery that has been accurately located a considerable expenditure of ammunition is allowable, provided continuous observation is possible. When a battery is being dealt with, shrapnel should be distributed in rear and on the flanks of the battery in order to catch the detachments. Fire should be kept up at intervals throughout the night to catch the men and teams who will probably be attempting to shift the guns.
- Registration.A form of target register is being issued to all batteries. All ranges must be reduced to the normal of 60° P. and 30" barometer before being entered up in the register. The "error of the day" can then be obtained by firing "sighting shots" at a plainly visible target, and this correction applied to the ranges obtained from the register. This register is to be handed over on relief to the incoming battery, or to the C.R.A. of the Division if the position is not being re-occupied immediately. To obtain full value from this method of registration, all guns must be carefully calibrated.
A Log Book in the form of an Address Book, showing all the information gained by a battery on its front, would be very helpful to a relieving battery.
Much ammunition is wasted by constant re-registration unless a systematic method is adopted and handed over to relieving batteries. A correction scale is being issued, and should be employed to reduce ranges obtained on any one day to the normal given above.
Observation stations and batteries must be adequately protected, and every precaution taken to conceal guns, detachments, and the approaches to a battery. As far as possible all movements in or near, the battery must be stopped when a hostile aeroplane is overhead, and nothing should be left lying about which would catch the eye of an observer, such as empty tins, &c.
The following information has been given by the R.F.C. :
- Positions are given away by
- Tracks leading directly to the guns and to no other place. Special precautions will have to be taken in case of snow.
- Guns placed in a straight line at regular intervals,
- The dark embrasures and entrances to dug-outs.
- Flashes. Gun flashes can be concealed by screens, from observation directly overhead, but not from the front unless the gun is firing in enfilade. Howitzer flashes can be concealed from the front, but not from overhead observation.
- The positions most difficult to locate and range on are those
- In broken ground, especially in the vicinity of heaps of rubble or mounds.
- Behind houses or in woods.
- When the guns are dotted about an open field at wide intervals.
- Where there is no prominent object close by to assist ranging.
- Hostile aeroplanes generally observe from a position over their own lines. A slight hedge about 150 yards in front of a battery has had the effect of "false cresting" the battery, as seen from an aeroplane, and resulted in the expenditure of many rounds on the hedge.
- An experienced observer is not deceived by dummy flashes unless these are very carefully engineered. The emplacements from which they are fired must appear to be occupied, and should have tracks leading to them. If possible a gun should occasionally be run in and fired from the position. The flashes must be carefully timed to coincide with the rounds from a battery that is actually firing.
- Unoccupied gun positions should not be left derelict. The gun emplacements should be kept intact to induce the enemy to believe that they are still occupied. They will often make good positions from which to fire flashes.
The underlying principle of all artillery communications is that it is of vital importance to enable the G.O.C. to bring overwhelming fire to bear on a given locality at the shortest notice.
Telephonic communications require careful supervision and co-ordination to avoid waste and confusion. A suggestion has been made that special communication trenches should be constructed for telephone wires only, and this may sometimes be possible. A multi-core cable containing 10 lines has been used with advantage to replace the same number of single ones. It can be well dug in and protected.
All the telephone equipment and wires of a battery should be under the charge of one man, who will be responsible for their maintenance. The signallers must not be allowed to tamper with telephone instruments.
Talking on the telephone leads to much conversation and often to inaccuracy in ranges, &c. It disturbs other people, and allows the signaller to forget buzzing, which may be the only means of communication in the noise of an action. Talking should be reserved for Officers. The signallers will then rapidly improve in buzzing, and it will eventually be nearly as quick as talking, and much more accurate.
Every endeavour must be made to supplement the telephone with visual signalling. Electric lamps are useful for this purpose, and signalling screens must also be obtained for use by F.O.Os. in case of emergency.
Every artillery officer should be a signaller, and can soon become so with half-an-hour's instruction daily.
N.B.These notes are not official.
"The Infantry cannot do with a gun less": The Place of the Artillery
in the British Expeditionary Force, 1914-1918