DEVELOPMENT OF A POSITION FROM AN OPEN WARFARE BATTLE
=General Use of Fortifications.= The first use of fortifications,
whether hasty or permanent, is to give shelter against hostile fire. The
more deliberate use of fortifications is to increase the holding or
fighting power of troops by the proper employment of the natural
defensive features of the ground and by artificial devices.
Successive Phases of the Organization
=Change from Battle Lines to Trenches of a Position.= During a battle,
as we understand it in open warfare, as soon as the fighting lines are
halted for any reason, every man immediately begins to dig in for
shelter against the enemy’s fire. If the halting of these fighting lines
is more or less permanent these “skirmish holes” are connected, and we
have the beginning of a rude trench. We must remember that in a battle
troops are disposed in depth in a series of lines. All these lines dig
for protection in a similar manner, giving the beginning of several
lines of trenches. If the troops remain for any time in this position,
it is necessary to have routes from the rear to the front to carry up
ammunition and supplies to the different lines. These communication
routes are also dug in, and we have the beginning of communicating
trenches. Soon the men will begin to seek better protection against
rain, cold, and overhead fire, and build themselves some kind of
shelters. In a similar manner command posts and supply depots are
established.
In time there is a complete skeleton of a series of lines of trenches
outlining a position. If the mission of the troops is to remain and hold
the ground, the necessary plan of organization for the final position
will have to be based upon this skeleton. The purpose of this new
organization, as we have noted, is to establish the position so that the
ground can be held by fewer troops.
=Active and Passive Elements of a Position, Especially Support Points.=
The first fire trench of a position is continuous, but it is not good
practice to man the whole of this line, because this would take too many
men and defeat the purpose of the fortifications. Secondly, a better
defense can be established by garrisoning a series of strong points, or
salients, from which can be obtained flanking fire. In the first line
these are called support points. The trenches connecting these support
points are retained as such, but are not usually manned. This curtain
trench, so to speak, is retained for communicating purposes, and to
deceive the enemy as to the real points of defense. A few watchers are
left in it.
The first line, then, is a series of support points, well defended by
men and special weapons, and at such distances apart as to support each
other.
=Division of Position.= The garrison of such a support point in the
first line is a company, and the captain is responsible for the holding
of this ground. (The platoon, we must remember, is a tactical unit.) In
dividing the first line into these active elements the size of each
support point depends upon the importance of the ground or of the
tactical situation.
[Illustration]
Similar natural strong points are also located in the second line. They
will be fewer and farther apart in this line than in the first line,
which is exposed to hostile attacks. These points in the second line are
connected with the support points and together the group is called a
center of resistance. The command of such a center of resistance,
including one or two support points in the front line, falls to a
battalion commander with his unit. For example, the area of a center of
resistance under the command of a Bn. C. O. will include, say, two
support points in the first line with a company in each, and the strong
point in the second line with two companies.
In the third line, also, natural strong points are located and organized
for defense. The command of this strong point, including, let us say,
two centers of resistance, falls to a colonel with his regiment. Such an
area is called a sector, or a sub-sector. If it is a sub-sector two such
constitute a sector in command of a brigadier-general.
=Different Lines of a Sector.= We have now arrived automatically at the
fact that each sector is composed of a series of lines in depth, each
defended in strong points.
The first line is termed the line of resistance, as the first defense is
made against the enemy’s attacks in the support points of this line.
[Illustration]
The second, or main line of resistance, is called the support line. In
the strong points of the centers of resistance are the reserves and the
headquarters of the battalion commanders.
The third line is called the covering line of the artillery, because it
defends the batteries distributed behind it. It also contains the
reserve troops of the sector, a battalion usually holding each strong
point. Here are established the headquarters of the colonel and the
different central depots of the sector.
The above three lines constitute one position. There may be several
positions in depth at distances of three miles or more apart. Usually
there are two positions and sometimes three. It is said that the Germans
have as many as six positions in depth in places. The first position
only, of course, is permanently occupied.
Principles of the Organization
=Advantages of the Continuous Trench.= The continuous or curtain trench
between support points must not be eliminated for several reasons. The
trench will deceive the enemy as to the location of the elements of
support points. If this trench were absent the enemy could easily locate
these, and subject them to concentrated artillery fire. The position
cannot be hidden from airplane observation but the essential elements,
such as emplacements, dugouts, etc., must be concealed.
[Illustration: Traces of Trenches Used to obtain Flanking Fire Types of
Communicating Trenches.]
The curtain trench serves for communicating purposes for lateral
movements of troops and for liaison between neighboring units.
The absence of the curtain trench would leave breaches in the line where
in a general attack units could concentrate and break through. In such a
general attack the curtain trench is occupied and defended by the
reserves. Barbed wire, of course, protects the entire front.
These trenches also serve, if necessary, as cover for reserves acting as
reinforcements to the adjacent support points, as there is only
sufficient shelter in a support point for its own permanent garrison.
Lastly they may serve as trenches of departure in the offensive.
=Importance of Flanking Fire.= It is possible to have the support points
at intervals because flanking fire from these will command all ground in
front. The importance of flanking fire cannot be overestimated.
Everything must be done to obtain it.
[Illustration: Type of a Good Entanglement in front of a Firing Line
Without Salients To Obtain Flanking Fire]
Sometimes it is impossible to obtain flanking fire because of lack of
salients. If this is true the trace of the first line trench must be
rectified to give flanking fire along the line as per diagram.
When neither of these two methods is possible small combat posts with
machine guns are located in advance of the line to obtain flanking fire.
The machine gun is the best weapon for flanking fire. Several
emplacements are constructed for each machine gun, but during the
bombardment it is kept under cover in a dugout. When the attack develops
the machine gun is quickly set up in the proper emplacement. If kept in
a permanent emplacement the enemy will soon locate it and put it out of
business by artillery fire.
If no emplacements are possible or if they are destroyed machine guns
are operated on open ground or in shell holes.
=Field of Fire.= With proper flanking fire a line can be defended with a
shorter field of fire than otherwise. A hundred yards of field of fire
is sufficient with good flanking fire and accessory defenses, such as
barbed wire, etc.
[Illustration: DIVISION OF POSITION INTO COMPARTMENTS FOR INTERIOR
DEFENSE]
=Location of Trenches.= Lines of trenches which are the result of a
battle are not always located in the most logical positions. They are
the results of the exigencies of the battle. However, it is well to know
the best locations for the trenches of a position under different
conditions in order to place them there when possible.
In flat country, of course, it makes no difference where the trenches
are located. On the profile of a hill, however, the question is where to
locate the first and where to locate the second line. Let us consider
Figure 15. Point A is out of the question as you have no view of the
enemy. At B you can observe the enemy’s line and he can observe yours.
However, the enemy can shell you at this point and observe the results.
At C the same conditions obtain as at B, except there is a dead angle
directly in front. At D you cannot observe the enemy nor can the enemy
observe your line. From these considerations we see that the proper
location for the first line will be at B as you must be able to observe
the enemy and all the ground in front. Your second line should be
located at D where the enemy cannot observe and bombard your position.
At D the line can be made as elaborate as you have time, men, and
material, because you are more or less unmolested by the enemy’s fire
and observation.
The reverse slope is of the very greatest importance in organizing a
position. Movements of troops and supplies can be easily accomplished
here under cover. Deep dugouts can be constructed with the least work.
But the greatest advantage lies during the bombardment. The enemy is not
able to observe the accuracy of his fire on the reverse slope so that
the elements in this line are left more or less intact. For this reason
the line on the reverse slope becomes the most important line of
resistance against the enemy’s attacks. The Germans habitually organize
their reverse slopes very strongly.
=Division of the Position into Defensive Compartments.= We have already
spoken of the sector in depth by successive lines. In the same way it is
necessary to organize the positions for lateral defense. A support point
may be captured by the enemy and from this ground he can launch a
flanking attack on the adjacent part of the position. It is necessary
that there should be an established defense against such an attack, and
for this purpose each sector is divided into compartments, so to speak,
with all-around defense.
Boyaux or communicating trenches on the flanks of these compartments are
organized as firing lines with barbed wire belts running parallel and
with machine guns disposed for flanking fire. We have then each sector
cut up into compartments capable of independent resistance in all
directions, if the surrounding compartments are captured by the enemy.
Such a compartment also has the advantage of serving as a base for a
counterattack against an adjoining one that has fallen into the hands of
the enemy.
In a sector the responsibility of such lateral defenses falls especially
upon the colonel.
=Concealment.= All of the essential elements of a position,
emplacements, dugouts, etc., are more or less without value if they can
be seen by the enemy and subjected to heavy artillery fire. Everything
that is possible must be constructed without the observation of the
enemy.
It is important to hide your works by making them fit in with the color
scheme and shape of the surrounding ground. False or dummy trenches,
emplacements, shelters, etc., are constructed to cause the enemy to
waste his ammunition. The art of camouflage is also extensively employed
for this purpose against both ground and aërial observation.
Elements of the Organization
=Plan of Organization.= We have seen that the first outline of the
trenches left as a consequence of the battle must be modified in detail
to obtain better protection and organization. The complete plan of
reorganization is laid down by the commander of the sector and is called
the Plan of Organization.
This plan is drawn up as soon as the position has a permanent garrison.
The Plan of Organization must be faithfully followed by all the
successive garrisons of the sector. After its adoption, even the
commander of the sector himself cannot modify the plan without the
consent of the general in charge.
The real value of the position depends upon the amount of continuous
work that has been done in carrying out the original plan.
=Outline of the First Line.= As was seen before, the original trace of
the first line was established as a consequence of the needs of the
battle. In the organization plan, it is necessary to introduce several
modifications in this trace. The commander responsible for this change
should place himself in the situation of the enemy and consider an
attack upon his own lines. From this consideration he will introduce
such modifications as will make this task as difficult as possible.
The responsibility of making this modification in the trace of the first
line does not devolve upon the captain in the first line. As a rule if
it were left to him few changes would be made because of lack of
initiative on his part, or because of fear that if the line were
captured he would be blamed for having changed it. This task falls upon
the battalion commander who is responsible for the center of resistance,
with the consent of the sector commander. The reason for this is that
the sector commander is the only one of these officers who knows the
subsequent use of this particular sector, whether for defensive or
offensive purposes. If for defensive purposes the line may be carried as
close to the enemy’s line as possible. If the sector is being organized
for an offensive there must be enough distance between to keep his own
line out of the zone of artillery dispersion when the target is the
enemy’s line.
=Cover Trench.= In general all fire trenches have a second trench
behind, called the doubling or cover trench. The use of the cover trench
is not primarily for defensive purposes. It has special uses.
[Illustration]
The majority of the troops in the first line are kept in the cover
trench in shelters located there. The first line is habitually manned by
only a sufficient number of men to assure observation and security. The
rest of the garrison remains in the shelters of the cover trench to get
as much rest as possible. It is very important that comfortable shelters
be located in the doubling trench. If troops are exposed to the elements
and bombardment their value decreases very rapidly. If the shelling
becomes too severe the men in the first line retire to the shelters of
the cover trench until the attack develops.
Another use of the cover trench in the defensive is to keep here a
necessary number of troops for reinforcing the first line when necessary
and for counterattack against the same if it is taken. This latter use
establishes the distance between the two lines, which is from thirty to
forty yards, so that hand grenades can be thrown from the cover trench
into the first line.
Behind each support point there is usually a lateral communicating ditch
called the circulating ditch which should not be confused with the cover
trench.
=Advance Posts.= In front of the firing line certain advance posts are
established. There are three kinds of these: listening, observation, and
combat posts.
The _listening post_ is not under the control of the commander of the
support point but is in the service of the Intelligence Officer. It is
furnished with a microphone for the purpose of picking up enemy’s
telephone messages in the hostile line.
The _observation post_ belongs to the sector and is used for purposes of
observation and security.
[Illustration: OBSERVATION POST]
The _combat post_ is established to obtain flanking fire along the
barbed wire entanglements or it is used as a bombing post when in close
proximity to the enemy’s trenches.
Sometimes a series of combat posts are connected and a new trench
established in front of the firing line. This is called the observation
line. It is best to avoid this practice as there is always the question
whether to hold or abandon this line when the enemy’s attack develops.
In either case there are grave disadvantages. If it is held you have a
weak line. If you abandon it the enemy can use it for shelter.
Advance posts give excellent service if not too numerous. If there are
many of them they are a temptation for hostile raids.
=Dimensions of Trenches.= These can be found in text-books on the
subject. The general idea is that they are to be narrow and deep to
prevent observation and to present a small target for high-angle fire.
=Loopholes.= Loopholes are used in the ordinary life of the trenches for
observation and sniping purposes; but against the real attack of the
enemy the firing is done over the parapet. If it is necessary to meet
the enemy in hand to hand combat the men climb up on the parapet.
=Traverses.= Traverses are used to localize the effect of shell or
grenade explosions, and to prevent enfilade fire.
They are sometimes used in long stretches of boyaux or communicating
ditches as emplacements for A. M. R. to enfilade the same if the enemy
penetrates the position.
=Transversal Lines.= Transversal lines are usually constructed between
the first and the second lines and between the second and the third
lines. They are short stretches of trenches parallel to the front for
special purposes: such as disposing of machine guns and trench mortars
in depth; bombing posts for rifle and hand grenadiers; depots and
observation posts.
Command posts are usually located in such small transversal trenches, a
little in rear of the lines they are in command of. For instance, the
captain in charge of a support point might be located in a transversal
just in rear of the cover trench.
=Support Trenches.= The second or support line is established at such a
distance that the first line is covered by its fire if the latter is
captured.
Also the second line should be placed so that it will be out of the zone
of dispersion if the first line is the artillery target either of your
own or of hostile fire. This places the distance between the two lines
at from 150 to 400 yards. At this distance also rifle grenade fire can
be used in conjunction with an artillery preparation for a counterattack
against the first line.
The organization of the second line is the same as that of the first; in
other words, the same principles and elements of defense are used:
making employment of barbed wire, flanking fire, cover trenches, etc.
The second line is the main line of resistance and must be made as
nearly impregnable as possible. For this purpose it must be thoroughly
and completely organized.
In the support line are the reserves of the C. of R. and for their
proper shelter they should have very deep dugouts, and all the
requisites for the comfort and rest of the troops.
=Redoubts.= Behind the support line is a redoubt containing the command
post of the battalion commander. It is the last strong point of the
center of resistance and is organized for an all-around defense.
The line of redoubts is the last line of serious resistance. If the
enemy penetrates this line a breach has been made in the position at
this point.
=Boyaux and Communicating Ditches.= As we have said before trenches for
communicating purposes must be dug both in depth and laterally. We shall
call those from front to rear boyaux, and those running laterally
communicating ditches.
The number of boyaux is not fixed as that of the different lines. There
must be at least one between each support point and its center of
resistance.
Usually boyaux are used for movements in both directions. Often certain
boyaux are designated for entrance only and others for evacuation. The
numbers of the latter are usually less than the former.
In an attack all boyaux are used for movements from rear to front.
All movements to the rear while reinforcements are being brought up must
be executed in the open ground, exceptions being made in the case of
wounded.
Boyaux are important for the movement of supplies and ammunition, but
above all they are essential for reinforcements during battle. The
greater part of the troops in a sector is held in reserve in the second
and third lines. This disposition is only possible if you have good
boyaux to the front lines.
All boyaux and communicating ditches are narrow and deep. Boyaux are
wider between the second and third line than they are between the first
and second. Evacuation boyaux are usually wider than others. The trace
of a boyau must be such as to prevent enfilade fire.
At intervals of about ten yards turnouts large enough for a stretcher
are constructed in the side of the boyaux for passage of troops in
different directions. Boyaux are named and signs are put up similar to
those for streets in a city. The same name of a boyau must be kept from
the third lines to the first.
At branches of the main boyaux they are dug a little deeper to avoid
mistakes of identification.
As was said before certain boyaux are organized for defense.
It may be said here that supplies carried up at night are usually
brought along on top of the ground close to the boyaux. This gives freer
movement and the carriers are close to the cover of the trench if
needed.
=Accessory Defense.= Of all the accessory defenses such as barricades,
abatis, trous-de-loup, etc., the most important by far is barbed wire,
which is almost exclusively used for obstacles.
Barbed wire should be placed from twenty to fifty yards in front of the
first line. At this distance shelling of the barbed wire belts will do
very little damage to the first line.
The wire entanglements must be under fire of the first line.
[Illustration: Command Post for Center of Resistance]
The trace of the wire belt is not necessarily parallel to that of the
firing line, but should be so placed as to obtain flanking fire along
the wire belts. Good entanglements are constructed in double belts, the
distance between the two belts being from ten to twenty yards, the
farthest belt, of course, being constructed first.
Breaches must be left through the wire entanglements for the passage of
patrols, friendly raiding parties, etc. Portable sections of barbed wire
are used to close these passages when necessary.
All accessory defenses must be concealed so they cannot be easily
observed and destroyed by the enemy.
=Command Post.= A command post, in the full sense of the word, contains
the headquarters of the leader of a division of a sector.
The command post must first of all be a good observation post, after
which the other requisites are installed. When the observation post has
been constructed the following are built: a room for the headquarters
staff to work and to sleep in, a telephone central, dugout for liaison
group, and a depot.
* * * * *
The preceding discussion is a development of a position from battle
conditions. On the other hand if you are unmolested by the enemy the
order of organizing a position would be as follows:
(1) Construct the emplacement to obtain flanking fire.
(2) Construct barbed wire entanglements.
(3) Observatory and dugouts.
(4) Trenches.