Lone Sentry: TM-E 30-451 Handbook on German Military Forces: Doctrine of Fortifications: Fortifications and Defenses

CHAPTER V. FORTIFICATIONS AND DEFENSES

Section I. DOCTRINE OF FORTIFICATIONS

1. Economy of Force

The Germans regard economy of force as a fundamental principle in designing fortifications. In conformity with this view, they employ defense works to permit a relatively smaller force to defend a line than otherwise would be required. German troops are taught that fortifications exist not for their personal safety but to enable them to fight more effectively, although fortified works, especially those of reinforced concrete, naturally make for a lower casualty rate. The German doctrine of offensive warfare therefore is not affected by the construction of strong systems of defense. Such systems in fact may be considered to be offensive rather than defensive in purpose, since they make it possible to concentrate a relatively large proportion of the field forces for action at any given point. In September 1939, the Westwall (Siegfried Line) [The Germans do not employ the term "Siegfried Line".] enabled the Germans to hold their Western Front with approximately 20 divisions, while employing 40 to 50 divisions against Poland. These latter troops, in turn, could be concentrated on the northern and southern parts of the Polish border for a double envelopment of the Polish forces, since the vulnerable central sector due east of Berlin was protected by the so-called Oder Quadrilateral, a zone of permanent defense works constructed between 1935 and 1939. Again, in May 1940, the Westwall played an important role—this time in the envelopment of the Maginot Line—for, while the French border was held with relatively weak forces, the bulk of the Wehrmacht wheeled through Belgium and Luxembourg.

2. Organization of Defenses

a. PRINCIPLE OF DEPTH. The Germans believe that a fortified line should consist of small works organized in great depth. This principle, embodied in the Westwall, is directly opposed to that of the French Maginot Line, which was a continuous wall of mammoth forts with little, if any, depth. The German idea is that a fortified line should not be employed to present an unyielding front to an attacker, but rather to act as a shock absorber and gradually slow down the advance. Then, when the attack has lost its momentum, counterattacks can be launched to destroy the penetration before the attacker has reorganized and consolidated his gains. The importance the Germans attach to counterattack is shown by the fact that they keep their best assault troops for this purpose and man the concrete positions with inferior soldiers. In order to impede the enemy's advance as much as possible and to facilitate the counterattack, troops manning the fortifications are taught to continue fighting even though their positions are overrun.

b. ZONES OF DEFENSE. The Germans achieve depth in a fortified line by constructing successive zones of defense. In a typical segment of the Westwall, there are three independent zones from front to rear.

(1) The Forward Zone (Vorfeldzone) contains field fortifications including trenches, barbed-wire entanglements, machine-gun emplacements, and observation posts.

(2) The Main Defense Zone (Grosskampfzone) comprises fortified structures such as pillboxes, casemates and shelters, and antitank obstacles covered by antitank guns. In addition, this zone has intermediate areas, front and rear, in which isolated works are placed at critical points along natural avenues of enemy approach.

(3) The Rear Defense Zone (Rückwärtige Zone) is much the same as (2), but is not as strong.

c. STRENGTH. It is the German practice to provide the weakest terrain with the strongest and most numerous defense works arranged in the greatest depth. But the defended zone is everywhere made as strong as the available resources permit, and no terrain is left entirely without the protecting fire of some permanent defense works.

d. SITING OF DEFENSE WORKS. Pillboxes and casemates in a fortified line are so spaced as to provide interlocking fields of fire between adjacent works, yet they are not so close together that hostile artillery fire which misses one structure will hit another.

In view of the German theory as to the purpose of fortifications, the principle of "effect before cover" is applicable; that is, a wide field of fire is considered more important in siting a position than cover or concealment. When possible, pillboxes and casemates may be sited to permit both frontal and flanking fire. This is particularly important since German doctrine directs that fortified positions be held even after the defensive line is overrun by the enemy. The fire plan of field artillery may be coordinated with the belts of fire from the fortifications so that concentrations can be laid on the areas where fire coverage from the fortifications is relatively weak.

e. FIELD WORKS. In accordance with German doctrine, concrete and steel pillboxes, and casemates are supplemented by extensive field fortifications to lend flexibility and mobility to the defense, to engage the enemy before he gets close enough to assault the main works, and to facilitate counterattack. Such field works are interspersed liberally throughout the Westwall and include minefields, obstacles, fire trenches for infantry weapons, and open emplacements for field artillery. Although open gun emplacements are intended to give supporting fire to pillboxes and casemates, they also can cover dead areas between the main works.

f. SHELTER. The German practice is to provide all troops with adequate shelter against weather and hostile fire. Concrete pillboxes and casemates often have accommodations for the gun crews, and open field works have underground shelters or dugouts adjacent to the firing positions. In a fortified line, underground shelters are provided in the rear of the battle zone for the reserves who are assigned to the counterattack. This is in accordance with the German doctrine that reserves should be committed as a unit, fresh, and without having had to sustain casualties or endure the strain of hostile aerial and artillery bombardment while waiting to attack. Personnel shelters enable the reserves to be kept close to the front so they can begin the counterattack with minimum delay.

g. COMMUNICATIONS. German fortified works commonly are linked together with communication trenches to facilitate relief of personnel, ammunition supply, and the care and evacuation of the wounded. In some cases a group of defense works is connected by a system of tunnels. Signal communication is provided by telephone cables buried in the earth, and often telephones communicate between the outside and the inside of a structure. Speaking tubes are installed in many of the works in case of failure of the telephone system.

TM-E 30-451 Handbook on German Military Forces		LoneSentry.com