Читать книгу Trench Warfare: A Manual for Officers and Men - Joseph S. Smith - Страница 5

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In locating the site for a defensive firing line, it must be divided into three sections:—firing line, immediate support and reserves. In doing this several opposing factors should be taken into consideration and their relative importance judged according to the special circumstances and objects in view, keeping in mind the probable lines and manner of defense of the enemy, and whether the trenches are for permanent or for temporary use.

This may be summarized under two heads: first, with the object of attaining the greatest field that can be covered by defensive fire; and, second, the greatest security from offensive fire.

It will even be found that these two constructions will be in conflict. Trenches placed behind the crest of a hill, say fifty to one hundred and fifty yards from the top, will hamper the accuracy of the enemy’s artillery fire. Shooting, to be effective, calls for a high rate of accuracy, and here the only observations possible are from aircraft and balloons; but the enemy side of the hill will be raised ground to the occupants of the trench. At night large numbers of the enemy could collect there, and the dangerous space to them would merely be the distance from your fire trench to the crest of the hill.

The enemy could and would entrench themselves on their side of the crest and by raising their parapet enjoy the advantage of a higher front, which would eventually lead to their entirely controlling the area behind your trenches, which are continually used by the relief and fatigue parties.

It is a principle that grazing rifle fire upon a defensive enemy is more effective than plunging fire, but any entrenched position higher than your own held by an enemy gives them a tremendous advantage. Regardless of what opinion may be held as to the maximum depth of a field of fire required to meet or repel attacks, whether in masse or open order, it should be obvious that the greater the depth of the field of fire and the more extensive the view of the enemy’s operations, the better it will be for the defending forces.

Protection from and localization of artillery fire must be provided by the internal construction of the trench rather than by a position that protects but also restricts the field of fire. There are frequently found in front of a firing line small areas of ground which are not covered by direct fire from your trench. A flanking fire frequently can cover these areas, but in spite of this, they must be watched constantly by means of listening posts or concealed observation posts, which may be hidden by the banks of rivers, hedges, ruined houses, or whatever natural existing concealment renders observation possible.

At night, it is a safe principle to support listening posts by automatic rifles, trip wires with noise making arrangements attached to them as common sense under the circumstances dictates. Great care and caution must always be taken to prevent the discovery of these listening posts by the enemy, and when discovered, alternative posts should be made or greater care taken for the protection of the men occupying these posts, such as overhead protection by mesh wire against bombing, and the upkeep of a small supply of bombs and close-range weapons in the post. The important trenches on the front having been located with a view of protecting the immediate front and with due regard to their relation, tactically, to the other trenches already located, the connecting trenches obviously must be subservient to the more important ones. Every endeavor must be made to avoid enfilade fires in the flanks, to give and to receive mutual support, and in particular to support those flanks which are not protected otherwise.

It is an essential consideration in the location of all these trenches that lateral communications can be established, and that supplies, supports, reserves, ammunition, etc., together with the means of retiring if necessary be taken into account. The distance from the water supplies and the possibility of concealing approaches is a further governing factor, although in many cases an ideal condition cannot be realized.

Then there is the counter attack, in case the fire trench should be taken, and the kind of soil which is so essential to its relation to bad weather and water seepage—these also require thought and study.

These things are main considerations to be kept in mind after a line has been settled on, whether during attack or whether siting trenches under common circumstances. It is not expected and is not necessary, when trying to obtain a position during attack, to keep all of these conditions in mind, but it is essential that when the attack has been finished and things return to slightly more normal circumstances, that these things be given instant consideration and proper action taken.

Were such a thing as concealment possible, it should be the first thing of importance to be kept in mind. Listening posts, machine gun positions, reserve dugouts, company, battalion and regimental headquarters, and similar things, at some distance behind or on fire lines, may be concealed, but fire-trenches are sure to be observed sooner or later (mostly sooner) by aeroplane and other means of observation, and it is best that one should admit the impracticability of concealment at once and take the proper protective measures. If opportunity for concealment offers itself, as it may do, according to the lay of the land, it should be taken always. It should always be kept in mind that one should try to place himself in the position of having the enemy’s point of view, both from his trenches and his aerial observations.

Advantage should be taken and even care given along trenches to the extensive cultivation of the weeds, grasses, etc., that may grow rapidly in the excavated soil.

It is, and always will be, a matter of much argument that trenches should not be dug near hedges, ditches, roads or rows of trees, on account of easy ranging mark given to the enemy artillery. In a country where such things are scarce, the idea may have a leg to stand on, but certainly to the Western Front it does not apply. It does not take artillery a moment to approximate by ranging shot, check by deduction or addition the range of trenches in any area, even if lying along a hedge or road. The ditch or hedge in some cases will provide the starting of a trench and offer fair amount of cover from fire to the troops working. A ditch immediately in front or behind the trench greatly helps to solve the many and varied difficulties of drainage, and when in front of a trench, can be made into a formidable obstacle, generally by throwing in varied lengths of barbed wire. Trenches under the cover of a hedge are very often safe from aerial observation, and even when located, sniping and observation can be carried on from them if the contours of the ground are favorable. It is always possible to do a certain amount of repairing and moving of troops only when unobserved from the enemy’s trenches. If advantage is not taken of these natural protections, such as hedges and trees, then they must be destroyed.

It is obvious that a great deal of labor can be lost and work thrown away if a policy is not adopted and continued. Battalions relieving one another up and down the line may waste a tremendous amount of labor unless the relieved officer’s policy is explained. If each commanding officer of a relieving battalion is permitted to air his own theories, duplication of work and lack of continuity will exist. Therefore, it is essential that the officers relieving the trench be thoroughly informed of work going on. With this object in view some of the officers of the relieving battalion should do a tour of duty (about 24 hours) before their troops take over the trench. An Officer and Non-Commissioned Officer are detailed from each relieving company for this duty. In the trench this officer is instructed by the senior officer present, and the non-commissioned officer by the ranking non-commissioned officer, in the policy to be continued. The commanding officer of the occupying company should have a sketch map of his sector of trench which he turns over to the relieving officer. This map should show the work under construction; proposed work; wire defenses; and if possible, the enemies machine gun emplacements, observation posts, snipers and work in progress. The notes accompanying the map should give the general conditions concerning the work—depth to which it is safe to dig, nature of soil, conditions regarding drainage, and all information in regard to the enemies’ activities during the period of occupancy. In addition, the relieving officer has the trench diary showing all the information covering every minute detail of the happenings during that company’s stay in the trenches. This diary is a continuous record of that particular sector and remains with the occupying company until it is relieved and then passes into the possession of the relieving half company, and so on, forming a continuous running record of the policy applying to the upkeep and methods employed therein. This diary, unless it is buried to avoid falling into the hands of the enemy, will continue until the end of the war. So every half company inherits one from his predecessor in the line upon its assuming the obligations previously assumed by its fore-runner, thus preventing a duplication of work and assuring continuity of endeavor.

There are certain obvious requirements that have to become rules. When required to fill sandbags, always look for the nearest excavation being made and fill from there, if distance permits.

As a matter of fact, in every trench there is a continuous revetting, widening of communications or control trenches, or driving of a tunnel to a listening post.

A—Parapet Traverse

B—Parados Traverse

TRAVERSED & RECESSED TRENCH.

Inasmuch as the time for filling sandbags is never ending, if work is being done and the earth is not absolutely needed for parapet or parados, the earth, if dry, should be put in sandbags, and, if necessary, stored until it is needed. The repair work that is most necessary takes precedent and is about as follows: Any damage to parados or traverses should be immediately attended to. During the night any damage to the wire entanglements must be repaired. Drainage comes next in order of importance, and this involves the digging of sumps and deepening of the drainage bottom. These are the repairs, but improvements must continually be made in the dugouts and communication trenches.

The ultimate design of a fire-trench depends upon its closeness to the enemy. When the latter are within 150 yards, the traversed fire-trench shown in sketch should be employed, as it provides adequate accommodation and protection for men who may at any moment be called upon to make use of bomb, bayonet and bullet; but if the enemy trenches are more than 150 yards distant, the ultimate design would depend upon the number of machine guns and automatic rifles available. Each of these guns has a firing capacity of about 25 rifles. Each gun therefore gives a reduction in the number of men required to hold the line, and in consequence reduces the amount of trench needed to protect these men.

A design, known as the “T” shaped fire-trench, makes an adaptable basis for entrenching under these conditions. Many lengths of a continuous traversed trench have no great field of fire, and yet, having been dug, they must be held, and unless properly held and kept in repair, they naturally become a source of danger.

As shown in the sketch, a traversed trench consists of a series of fire-bays interrupted by a series of traverses. The object of these being to localize the effect of shells or bombs landing in a fire-bay, and preventing enfilade fire down the length of the trench, as well as localizing any entry of the enemy into your line.

Dimensions vary up and down the line. Sometimes according to the lay of the land, sometimes according to the opinions, whims or fancies of the regiments making them, but the following dimensions should be kept in mind, and it will be found that they show the average of the whole general line on the Western Front.

Fire-bays generally are from 12 to 18 feet long (defendable by 4 to 6 men, but accommodating 8 to 12, when necessary) plus a 2-ft. covered sentry box recessed into the traverse and giving room for one more man; this depending entirely on the energy and initiative of the men occupying the section.

Every traverse averages 9´ x 9´ which includes a fairly liberal allowance for wear and tear, and is the minimum allowance for stopping enfilade fire and localizing fire. As the width from front to rear varies, depending on the amount of shell fire, it should be wide enough to allow a certain amount of lateral traffic without interfering with those who may be firing. Three feet may be taken as the maximum width at the bottom of the trench, that is, 1½´ for traffic and 1½´ for those firing, with a slope to the sides of from 10 to 15 degrees from perpendicular, thus lessening the tendency of the walls, whether revetted or otherwise, to slide in.

The depth of the trenches varies also, for the same reasons that cause the width to vary. Recesses should also be dug at various and favorable places for the storing of ammunition and bombs.

When digging entrenchments without regard to concealment, the excavated soil is first of all thrown to the front or enemy’s side of the trench, thus temporary cover is obtained. When the entrenchment has reached the proper depth the artificial raising of the ground is leveled. The artificially raised portion is known as the parapet. On the completion of the parapet, the soil is thrown to the rear side of the trench, thus forming the parados which gives a protection from the rear. It is not a good policy to excavate in front of the parapet, but to get additional height and thickness as quickly as possible this is often done. Unless carefully watched, men will dig this dirt from places as near the parapet as possible, resulting in the weakening or total undermining of the parapet or trench wall. The more gradual the forward slope of the parapet, the more does it approximate as it should to the glacis of a fort, consequently giving less cover to an attacking enemy. Make use of the ditch or holes from which the dirt was obtained, as a strong obstacle immediately in front of your trench, where the enemy at the last moment may be held up to go under a very severe rifle and bombing effort. In normal circumstances, by which I mean when not exposed to an unduly vigorous machine gun or artillery fire, the soil should not be taken from in front of the trench in the manner described above, closer than 10 to 15 feet from the actual parapet, unless the holes are adequately protected by trip wire, as well as barbed wire. Cases have occurred when valuable information has been obtained by the enemy lying in holes thus dug and not properly protected.

The parapet should be kept as low as possible and made to blend with its surroundings as much as possible. This is done by taking great care to cover any signs which show that fresh work has been done, even to the extent of actually planting grasses, weeds and roots, such as grow in the immediate neighborhood, and giving every encouragement to those that already grow. This greatly hinders the enemy’s artillery, as it changes positions up and down the line; interfering with and hindering the observations and accurate ranging by their forward observing officers, checking charts turned over by relieved batteries.

Bullet-proof nature of a parapet naturally depends on the soil of which it is composed. Although it is not necessary to memorize the minimum of safety, you should keep a general rule in your head. The parapet should not be less than five feet, regardless of the kind of soil. When the trench has been carefully sited for the actual field of fire from a ground level, this thickness is best obtained by raising the ground level artificially as little as possible and getting the necessary depth by digging, unless prevented by moisture.

Unnecessary casualties are caused by the practice of putting a single row of sand bags along the top of a parapet for temporary purposes of concealment, as it gives a faulty idea to the men in the trench as to the real height of the parapet.

The parados gives protection from the effect of shell fire bursting behind the trench, and should be made fire-proof as soon as possible, although it is not necessary unless concealment is possible to level it down in a similar manner to the parapet. As a matter of fact, it should be at least a foot higher than the parapet, thus providing a background for the parapet. It has been known to happen that when the occupants of a trench have been reached by the enemy they have vacated their trench and used the parados as a parapet, much to the surprise and disgust of the enemy. In a high and irregular parados, places could even be found which when not used steadily provide unexpected and safe observation and sniping posts, but care must be taken that they are not used too often.

If a trench were used merely for firing, 4½ feet from bottom of trench to top of parapet would be a sufficient depth. During attack, however, when fire from loopholes is too restricted, exposure of head and shoulders over the parapet becomes necessary, but it is not necessary to expose men moving along the trench and not actually firing. If the trench should be 7´ or 8´ deep, you must provide a platform at the bottom of the front wall 1¼´ wide and 4½´ from the top of the parapet. This is called a fire-step. The rest of the trench can be deepened to any desired depth, depending on the energy displayed. If of an extraordinary depth, steps must be cut to the fire platform.

In a great many different parts of the Western Front, especially Belgium, it was found that after digging to a depth of one to three feet water was encountered to such an extent that it became impossible to dig any sort of a trench which would give adequate protection to the men involved.

Fire Trench.

Supervision Trench.

Link Trench.

When these conditions are run into, breast work parapets must be artificially built up above ground level with soil, sods and sandbags, supported by sandbags, hurdles or close wire netting, revetment and stakes. The same principles of thickness, depth, width, slopes, and in fact everything that applies to a dug-in trench, applies to breast works.

A—Link Trench, minimum length 5 ft.

“S” & “T” Trench.

The “T” trench has many more advantages than the few mentioned in the opening of this chapter. T fire-bays may be single, double or treble (that is with one, two or three bays). Fire-bays in any length up to 15 feet with 8 feet traverses are for firing purposes only, and the control trench, sometimes known as the lateral communication trench, as its name implies, giving lateral communications, is used for that purpose only. Therefore, the fire-bays and control trenches can be narrower than trenches which have to be used for both purposes, thus lessening the amount of repair and revetment work required. And the intervening ground between these fire-bays gives the same result as a traverse used in a traversed trench system, and saves the labor of digging a more intricate system. The control trench gives an officer or N.C.O. in charge of the T bays a chance to handle his men and fire in these bays without struggling around innumerable traverses and wasting time very often when a minute lost or gained means lives lost, or part of a trench system in the hands of the enemy.

T bays may be sited with due and careful consideration while facing the enemy in an existing trench system. Thus it gives you the advantage of being able to take into consideration all the requirements of the field of fire, control of isolated areas, and the obtaining of maximum results from enfilade fire. These T trenches may be dug out from the old system without undue exposure of your men and if distance between the lines permits, and it is entirely possible to construct a new and generally more favorable line of trenches within 100 to 200 yards of the enemy’s trenches. Intervening ground between these T bays must be completely controlled by entanglements and mobile machine guns, or automatic rifles, able to operate from different alternating recesses in the control trench. Fire platforms should be placed in recesses at intervals in the control trench from which covering fire can be given. Artillery fire, to damage a T trench, must be very accurate. In a traversed trench a shell destroys not only lateral communication, but the defenders as well, whereas with a T shape, both fire-bays and control trench have to be ranged and hit. The success of the enemy is entirely local when capturing one of these T-bays, and he may be shelled by your own artillery without any danger or risks to those defending their T-bays. Control trenches should be dug first and zigzagged with the longer stretches facing the enemy. This gives you another fire-trench as well as a communication trench, and is also ready for use at any time needed before the T-bay is completed. On the completion of the T-bay, the corners of the zigzagged trench must be rounded off to make it easier and quicker for the movement of troops and carrying of stretchers.