SUBCOURSE EDITION EN0065 B FIELD FORTIFICATIONS ENGINEER SUBCOURSE 65 FIELD FORTIFICATIONS CORRESPONDENCE COURSE PROGRAM U. S. ARMY ENGINEER SCHOOL FORT LEONARD WOOD, MO INTRODUCTION Field fortifications are natural or manmade protective features used as defensive obstacles, personnel and weapons shelters, and protected firing positions. This subcourse teaches you how to construct personnel, vehicle, and weapons emplacements, intrenchments, shelters, entanglements, and obstacles under various climatic conditions. Standard plans, types of material, construction procedures, and estimated time and labor requirements are also given. The subcourse consists of five lessons and an examination as follows: Lesson 1. Purpose and Requirements of Field Fortifications. 2. Trenches, and Fieldworks. 3. Obstacle Employment. 4. Barbed Wire Entanglements. 5. Camouflage (Protection Against Enemy Surveillance). Examination. Fifteen credit hours are allowed for this subcourse. The format of this subcourse has been developed to facilitate student self-pacing and self-testing. Each lesson in this subcourse is followed by a number of Self-Test questions and exercises designed for a review of that lesson. After completing study of the lesson, you should answer the Self-Test exercises, then turn to the back of the subcourse booklet where the correct answers to the Self-Test have been included. A comparison of your answers with those given in the back of the subcourse will indicate your knowledge and understanding of the material presented. When you have completed all lessons to your satisfaction, complete and forward the Examination Answer Card which you will find in the subcourse packet. The grade you receive on the examination is your grade for the subcourse. * * * IMPORTANT NOTICE * * * THE PASSING SCORE FOR ALL ACCP MATERIAL IS NOW 70%. PLEASE DISREGARD ALL REFERENCES TO THE 75% REQUIREMENT. i LESSON 1 PURPOSE AND REQUIREMENTS OF FIELD FORTIFICATIONS CREDIT HOURS.......................................................................................................... 3 TEXT ASSIGNMENT.................................................................................................. Attached memorandum. LESSON OBJECTIVES Upon completion of this lesson you should be able to -- 1. Basic Requirement of Field Fortifications. Describe the basic requirements for field fortifications to include efficient employment of weapons, protection qualities, and progressive development. 2. Protective Measures Against Nuclear Weapons. Describe protective measures against nuclear weapons to include before, during and after explosion actions and procedures. 3. Individual Emplacements. Describe construction methods for individual emplacements to include skirmisher's trench, improve emplacement, one-man fox hole etc. 4. Crew Served Infantry Weapons Emplacements. Describe construction of infantry weapons emplacements to include machine gun emplacements, emplacements for recoilless weapons, etc. 5. Vehicle and Artillery Emplacements. Describe construction of vehicle and artillery emplacements to include vehicle pit, towed artillery weapons emplacements, and self-propelled and tank-mounted weapons emplacements. 6. Firebase Construction. Describe construction of a firebase to include layout, artillery requirements, and construction tasks in Phases I, II, and III. 7. Deliberate Shelters and Bunkers. Describe construction of deliberate shelters to include general construction requirements, sectional shelters, bunkers, overhead cover, and standoff. 8. Prefabricated Shelters and Bunkers. Describe construction of prefabricated shelters and bunkers to include design considerations of the WES concrete arch bunker, and WES concrete arch shelter. 9. Protective Shelters for Frozen Environment. Discuss the barriers and shelters which can be constructed of snow or ice and the qualities of snow and ice as protective materials. 1-1 ATTACHED MEMORANDUM Section I. Purpose and Protective Requirements of Field Fortifications 1-1. USE OF FIELD FORTIFICATIONS cannot disperse sufficiently to obtain adequate protection. a. On the offense. During offensive operations periodic halts may be required to e. Alternate and dummy positions. When regroup, resupply, or consolidate positions gained. time and the situation permit, dummy and alternate Where the enemy threat is known to include a positions should be constructed to deceive the counterattack capability (or probability), offensive enemy and to allow flexibility in the defense. units should seek available cover or should dig hasty emplacements. 1-2. RESPONSIBILITIES b. On the defense. A defensive position is Field fortifications are constructed by personnel built around a series of organized and occupied of all arms and services. Hasty shelters and tactical positions. Positions are selected for their emplacements are normally constructed by the natural defensive strength and the observation combat units occupying the position. Some afforded. Fortification measures include clearing engineer equipment and supervisory assistance are fields of fire, digging weapons emplacements and frequently required to assist the combat units. positions for personnel, strengthening natural Fortifications of a more complex character may obstacles, installing artificial obstacles, and require construction by engineer troops. Actually, providing camouflage. engineers at all echelons of command assist in the preparation of plans and orders and furnish technical c. Fortification plans. Plans for fortification advice and assistance in the construction of field not only provide for the desired degree of protection fortifications. but also for bringing the enemy under the maximum volume of effective fire as early as possible. 1-3. BASIC REQUIREMENTS FOR Fortification plans are usually based on progressive FORTIFICATIONS construction, that is, proceeding from open to covered emplacements and shelters, to the ultimate a. Employment of weapons. Emplacements protection permissible under the circumstances. must permit effective use of the weapons for which Characteristics of personnel and individual weapons they are designed. This requirement may limit the emplacements are shown in table 1-1 (in back of protection which can be provided and may influence course booklet). the design and depth of adjacent shelters. d. Dispersion. The separation of units and b. Protection. As far as possible, protection individuals is a primary means of protection, should be provided against hazards except a direct particularly from the effects of nuclear weapons. If hit or a close nuclear explosion. To obtain the area occupied by a unit is doubled, it is less maximum protection, excavations should be as small vulnerable to shell fire or the effects of nuclear as possible, thereby limiting the effective target area weapons. Proper dispersion can greatly reduce the for high trajectory weapons and airbursts. requirements for high level protection from field fortifications. The amount that a unit spreads out c. Simplicity and economy. The depends on the mission, terrain, and the enemy emplacement or shelter should be strong and simple, situation. Fortifications, properly employed, can be require as little digging as possible and be used in lieu of, or to supplement, dispersion, but constructed with materials that are immediately fortifications are particularly important for units that available. 1-2 d. Progressive development. Plans for infantry heavy weapons, bombs, and other serial defensive works should allow for progressive weapons. Advantage should be taken of all development to improve the usefulness of the available natural cover. Improvement of the fortification. Development fortifications can be position continues until the unit leaves the area. accomplished in three steps -- b. Overhead cover. Overhead protection is (1) Digging in quickly where speed is the important particularly in the forward areas where principal consideration and no special tools or the threat includes airburst shelling in addition to materials are required. the possibility of nuclear attack. Covered firing positions should be built for individual riflemen. (2) Improvising with available materials. Small readily accessible shelters adjacent to weapons emplacements are also necessary. A (3) Refining, using stock materials. minimum of 15-20 centimeters (6-8 inches) of logs, 45 centimeters (18 inches) sandbags, rocks, and e. Camouflage and concealment. Fortifi- dirt, in that order, is required for overhead cations should be built so that the completed work protection. Any available material may be used but can be camouflaged. It may not be practical to cover should be kept low. However, cover of this conceal a defensive position completely, but it type will not protect personnel against direct shell should be camouflaged enough to prevent the enemy hits. Overhead cover should be strengthened and from spotting the position by ground observation. If improved as long as the position is occupied. Only possible, dummy positions should be constructed the part of the firing position should be covered. same time as the actual position. Sandbags are placed over the logs to prevent dirt from falling on the occupants. f. Ingenuity. A high degree of imagination and ingenuity is essential to assure the best use of 1-5. PROTECTION FROM CHEMICAL available materials as well as the best choice and AND BIOLOGICAL WEAPONS use of the fortifications constructed. Open or partially open emplacements afford no 1-4. PROTECTION FROM protection