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'WAR DEPARTMENT FIELD MANUAL

FM 17--45

THE ARMORED ENGINEER

BATTALION

WAR DEPARTMENT - 1 JUNE 1 f44

4 IN &i-~ A TION OF RESTRICTED ,ATTER. -The Inlor-marion contained in restricted documents and the esientiol charcteristicsof restricted material may be given to any person known o be-in theservice of the United States and to persons of undoubted loyalty anddiscretion who are cooperating in Government work, but will not becommunicated to the public or to the press except by authorized militarypublic relations agencies. (See also pro. 23b, AR 380-5,15 Mar 1944.)

United States Government Printing Office

Washington 1944

WAR DEPARTMENTWASHINGTON 25, D. C. 15 JUNE 1944

FM 17-45, The Armored Engineer Battalion, is pub-lished for the information and guidance of all concerned.

BY ORDER OF THE SECRETARY OF WAR:

G. C. MARSHALL,Chief of Staff.

OFFICIAL:

J. A. ULIO,Major General,

The Adjutant General.

DISTRIBUTION:

As prescribed in paragraph 9a, FM 21-6: exceptposts, camps & sta (0), ROTC (0), Armd Sch(500); B 17 (2); Bn 17 (2); 1 Bn 2, 6, 7 (2); 5 (5);C 17 (2); 1 C 2, 6, 7, 17 (2), 5 (15).

I Bn 2: T/O & E 2-25, Cav Rcn Sq, Mecz, ArmdDiv.

I Bn 5: T/O & E 5-215, Armd Engr Bn.I, Bn i:-T/O & E 6-165, Armd Field Artillery Bn.

- IB 367:iT/Q & E 7-25, Armd Inf Bn.I C 2: T/F,& E 2-26, Hq & Hq & Sv Tr, Cav

Rcn Sq;, k ecz; 2-27, Mcz or Rcn Tr (Cav) RcnSq; 2-28, Tr E, (Cav Assault Gun) (Rcn SqMee.

1 CG 5:-T/O & E 5-216, Hq & Hq Co, Armd Engr- n;-5-217, Co, Armd Engr Bn.I C 6: T/O & E 6-160--1, Hq & Hq Btry, Div

Arty, Afptd-:Div; 6-166, Hq & Hq Btry, ArmdFA: Bn-.:6-167, Btry, Armd FA Bn; 6-169, SvBtriJArmd FA Bn.

I C 7: T/O & E 7-26, Hq & Hq Co, Armd InfBn; 7-27, Rifle Co, Armd Inf Bn; 7-29, Sv Co,Armd Inf Bn.

I C 17: T/O & E 17-17, Lt Tk Co, Armd Regt.For explanation of symbols, see FM 21-6.

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TABLE OF CONTENTS

Paragraphs PageSection I. General ------------ 1-9 1

II. Staff Duties, Orders,Liaison __--------- 10-13 11

III. Training ------------ 14-20 14IV. Reconnaissance --_-- 21-24 17

V. Marches ------------ 25-26 25VI. Security ------------ 27-31 26

VII. Offensive Action ---- 32-38 38VIII. Defensive Action and

Retrograde Move-ments ------------ 39-42 56

Appendix Characteristics of ArmoredDivision Vehicles ---------------- 62

FM 17-45

WAR DEPARTMENT FIELD MANUAL

THE ARMOREDENGINEER BATTALION*

(This. manual supersedes FM 17-45, 13 November 1942 and Cl)

Section I

GENERAL

1. PURPOSE. This manual covers the tactics andtechnique of the armored engineer battalion. It sup-plements basic and engineer field manuals and engineertechnical manuals, and will be used in conjunction withthem in training the armored engineer battalion and itscomponent parts.

2. MISSION. a. The mission of the armored engineerbattalion is to facilitate the operation of the armoreddivision of which it is an organic part. To accomplishthis mission, the battalion is trained and equipped to-

(1) Reconnoiter and mark roads, trails, and otherroutes.

(2) Reconnoiter bridges, defiles, obstacles, and areas.(3) Construct, improve, or reinforce fords, bridges, and

culverts.(4) Construct and maintain floating bridges and

ferries."For definition of military terms not defined in this manual see TM20-205".

1

(5) Transport infantry elements across streams withassault equipment.

(6) Construct and remove obstacles, including deliber-ate mine fields.

(7) Establish and operate water points.(8) Execute demolitions.(9) Assist in the assault of fortifications.(10) Locate, and, if necessary, prepare advance land-

ing fields.(11) Fight as infantry.b. For further details of engineer duties see FM 5-5

and FM 5-6.

3. ORGANIZATION. The armored engineer battalionconsists of a headquarters and headquarters companyand three engineer companies (Figures 1 and 2). De-tails of organization are shown in current tables of or-ganization and equipment.

4. EMPLOYMENT. a. The armored division, with itslarge number of heavy vehicles operating at great speed,requires considerable engineer support for maximumbattle effectiveness. The armored engineer battalion isspecially equipped to furnish the prompt support de-manded by tank units. It is trained to work rapidly,utilizing power tools and other time-saving expedients:Armored engineers should be used economically, andshould not be dissipated on unimportant or unnecessaryassignments. They should be supported closely by otherengineer troops, who can take over ford and bridgemaintenance, and similar tasks, and release armored en-gineers to accompany the division. Armored engineersare employed on infantry missions only when such em-ployment is definitely determined to be more urgentthan engineering work.

b. Engineer elements should be well forward in com-bat groups so that necessary engineer work can bestarted with a minimum of delay. The engineer reserveshould be placed well forward.

2

5. ENGINEER ATTACHMENTS. a. Armored engi-neer units are attached to other units of the division asrequired by the situation. The division engineer is pre-pared at all times to recommend to the division com-mander the strength and composition of these attach-ments. He keeps himself informed constantly as to thetactical situation, the terrain, road nets and their capaci-ties, and the availability of engineer materiel and sup-plies. Due to the speed and dispersion of armored unitsin battle and the resultant difficulty of reinforcing them,initial engineer attachments are relatively strong. Underaverage conditions, attachments to major combat groupsvary from a platoon to a company, depending on the sizeand engineering requirements of the attacking forces.

b. The commander of each attached engineer unitshould recommend to the commander of the unit towhich he is attached a method of utilizing the engineers.

6. ENGINEER EQUIPMENT. To facilitate its promptemployment on independent tasks, each squad of theengineer battalion carries in its vehicle certain carpen-ter, pioneer, and demolition equipment and limitedquantities of engineer supplies and antitank mines. Ad-ditional equipment and supplies are carried in platoonand company transportation. Each company has a mo-torized air compressor with power tools. Each letteredcompany has a tractor with dozer. Headquarters com-pany equipment includes a treadway ferry set. There isno bridge company in the battalion.

7. DEFENSE. Armament of the battalion includesrocket launchers, caliber .30 and caliber .50 machineguns, and individual weapons. It has no antitank guns.Engineer units can defend themselves against patrolsof infantry and lightly armored vehicles. When attackby large or heavily armored forces is probable, engineersmust be supported by other troops.

8. COMMUNICATION. The battalion is equippedwith a limited number of radios and messengers. For

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NOTE: Because of the limited range of the SCR-510radio set, the engineer reconnaissance section has noorganic means for transmitting information rapidly fromits forward position with the division reconnaissancebattalion to the engineer battalion headquarters. It isimperative that information concerning the condition ofroutes and the location of obstacles and possible engi-neer supplies reach the division engineer promptly andcontinuously from the reconnaissance section. The divi-sion commander may insure prompt delivery of thisdata by one of the following means:

a. Ordering assignment to the reconnaissance sectionof sufficient SCR-506 radio sets from the reconnaissancesquadron or the division signal company.

b. Designating a definite precedence for transmis-sion of the information over the division reconnaissancenet (FM 17-70). This may be done by setting the hourswhen such information will be given precedence, pro-vision being made that this does not prevent transmis-sion of important information at other hours. A repre-sentative of the division engineer is present at divisionheadquarters at all times to receive information directlyfrom the G-2 and obtain any necessary clarification.

9. SUPPLY. The principal engineer supplies for thedivision are water, maps, explosives, bridge materials,camouflage materials, and in certain situations, materialsfor field fortifications. The division engineer is the engi-neer supply officer of the division (FM 101-5). Requi-sitions for engineer supplies (except water and maps)clear through division headquarters where the divisionengineer edits and alters them in accordance withpriorities determined by the tactical situation and avail-ability of supplies. Requisitions as edited are forwardedto Army, which notifies the unit through division head-quarters where and when the supplies can be drawn.The using unit then obtains the supplies in its own ve-

7

hicles from the Army depot. In cases where the divisionengineer has under his control locally procured engineelsupplies he deletes such items from the unit's requisitionbefore forwarding it to the Army and then notifies theunit of the place and time it may be drawn.

a. Water. (FM 5-6) Water for the division is usuallyprovided from local sources by using the organic water

ARMORED ENGINEER BATTALIONRADIO NET

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purification units which are part of the equipment of theengineer headquarters company. Water points are es-tablished as needed. All water is habitually filtered andchlorinated unless declared safe by medical authority.After treatment it should be similarly approved prior todistribution, Water is drawn by the using unit employ-ing its own vehicles and water cans. When local sourcesare inadequate, water is brought from the rear.

b. Maps. (FM 5-6) The division engineer normally ob-tains maps from the engineer of the next higher unitand distributes them under supervision of the divisionG-2.

c. Explosives. A large quantity of explosives is carriedby the armored engineer battalion. This includes severalthousand pounds of both TNT and ammonium nitrate aswell as blasting caps and detonating cord.

d. Bridge materials. Heavy lumber and other materialsfor the construction or reinforcement of bridges is pro-cured locally, when available, or drawn from armyengineer supply points. Each platoon normally carriesa small quantity for emergency work, and a greateramount when need can be anticipated.

e. Camouflage and field fortification material. Suchmaterials needed by engineer troops are drawn directlyfrom Army or procured locally.

10

Section II

STAFF DUTIES, ORDERS, LIAISON

10. DUTIES OF DIVISION ENGINEER AND AS-SISTANT (FM 101-5) a. Division engineer. The com-manding officer of the battalion is also the division en-gineer. The principal staff duties of the division engi-neer are-

(1) Advise the commander and staff on all engineermatters.

(2) To recommend to the division commander thestrength and composition of engineer attachments, andas a staff officer supervise their execution of engineertasks.

(3) To prepare current and future plans for the use ofthat part of the engineer battalion not attached to com-bat commands or other units, and supervise the execu-tion of the plans as approved.

(4) To supervise the collection and dissemination ofengineer reconnaissance data.

(5) To coordinate engineer supply for the division.(6) To recommend traffic circulation plans, and su-

pervise preparation and posting of signs for markingroutes. (FM 100-15)

(7) To plan and construct defensive works whenspecially directed.

(8) To construct, maintain, repair, and operate struc-tures and utilities when specially directed.

(9) To plan and supervise execution of instruction andmeasures concerning engineer work for the division.

b. Assistant division engineer. The assistant divisionengineer is habitually at the forward echelon ofdivision headquarters. He is the representative of thedivision engineer, and is the liaison officer from the en-gineer battalion. In the performance of his duties, he-

ll

(1) Keeps a situation map showing the condition ofroutes and bridges, the location of natural and artificialbarriers and of defiles which can be blocked, the ford-ability of streams, the location of materiel usable forengineer supplies, and other similar information.

(2) Presents pertinent engineer information to thedivision commander and staff.

(3) Works in close cooperation with G-2 on recon-naissance information and map procurement, with G-3on plans and operations, and with G-4 on traffic circu-lation and water and engineer supply.

(4) Collects and forwards to the engineer battalion allavailable information that will assist it in the perform-ance of its tasks.

11. DUTIES OF ENGINEER BATTALION STAFFOFFICERS. Duties of staff officers are described inFM 101-5. Specific duties of engineer battalion staffofficers are described in detail in FM 5-5.

12. ORDERS. a. Oral orders, frequently fragmentary,are customary. Warning orders are issued when possible.Use sketches, overlays, and marked maps to simplifyorders. Be certain that orders state a definite mission.Give them in such form that they cannot be misunder-stood. The form of a field order is given in FM 101-5.

b. The adoption of standing operating procedure re-duces the amount of routine detail contained in orders.Standing operating procedure should not become volum-inous, and must not be so rigid that it interfereswith the flexibility of units or the initiative of their com-manders. FM 5-6 contains a list of subjects suitable forinclusion in a standing operating procedure. That list isa guide only. It is varied as necessary to conform to thestanding operating procedure of the armored divisionand to fit the particular needs of the battalion.

13. LIAISON. a. The assistant division engineer is the

12

engineer liaison officer at division headquarters (seeparagraph 10).

b. An attached engineer unit provides a liaison agentat the headquarters of the unit to which it is attached.

c. General duties of liaison officers are prescribed inFM 101-5.

13

Section III

TRAINING

14. GENERAL. a. The fundamentals of training areprescribed in FM 100-5, FM 21-5, and FM 5-5. Specialinstructions are published in periodic training directives.

b. Training of the armored engineer battalion mustbe well-planned, thorough, and intensive. Armored en-gineers must gain proficiency in the use of many kindsof special tools, equipment, and vehicles, and be pre-pared to perform a large number of widely varied tasks.They must be capable of executing these tasks withgreat speed under hostile fire, and often with improvisedmeans or materiel.

15. INDIVIDUAL. Newly-activated units receive en-listed men directly from reception centers, and the firstmonths after activation are devoted to basic training.Replacements usually come from engineer or armoredreplacement centers. Trainees learn to perform normalengineer tasks while undergoing squad, platoon, andcompany training. Specialized instruction is carried onin unit schools and service schools.

16. SQUAD. Under its regularly assigned squadleader, the squad learns to perform engineer and combatmissions as a unit. Training includes-

a. Care, operation, and employment of the squad ve-hicle and weapons.

b. Performance of typical armored engineer work,such as hasty construction and repair of bridges and cul-verts, placing and removal of antitank and antipersonnelmines, demolitions, and squad tasks in construction offerries and floating bridges.

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c. Continuous practice in providing local security forthe squad's own working parties (see Section VI).

d. Combat training, similar to that of the armored in-fantry squad (see FM 17-42).

17. PLATOON. a. The engineer platoon is the basicengineer work unit, although each of its three squads istrained to perform normal engineer tasks. Under all butthe most unusual conditions, the platoon remains underthe control of its platoon leader in both training andcombat; it should not be subdivided into smaller attach-ments or details. Training of the platoon emphasizes-

(1) Independent execution of typical engineer tasks.(2) Coordination of the squads for efficient perform-

ance of platoon tasks.(3) Local security (see Section VI).(4) Combat training, usually in connection with engi-

neer operations, but similar to training of the armoredinfantry platoon (see FM 17-42).

b. All engineer platoons receive the same type oftraining, but an important difference of equipment thatexists between the platoons of a company may affecttheir employment. Of the three platoons, one is mountedin armored half-track vehicles, and two are transportedin 21/2-ton dump trucks. Performance of most engineertasks is not affected by this variation, but under someconditions the equipment may govern. In particular, theplatoon mounted in half-tracks may be called upon foroperations that bring them under enemy ground fire(paragraph 22).

18. COMPANY. a. Engineer company. Training of theengineer company consists of developing the teamworkof the three platoons and the company headquarters,plus the training of the specialist personnel in companyheadquarters. The technical training of the company isaccomplished best by employing it upon definite engi-neer tasks.

b. Headquarters company. All men of headquarters

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company receive basic training. Specialists receive ad-ditional training. Specialist training is the responsibilityof the company commander except for men under thecontrol of battalion staff officers.

19. BATTALION. a. General. Battalion training pri-marily consists of the coordination of the operations ofthe lower units by the battalion commander and thebattalion staff. Practice of these command and stafffunctions should be as rigorous and continuous as themore technical phases of training.

b. Schools. The battalion conducts schools to instructofficers and enlisted specialists in technical subjects. Useis made of divisional and branch schools when they areavailable. Training films and similar aids are used, butpractical application, particularly under field conditions,is the most important part of the training.

20. COMBINED TRAINING. a. Armored engineersare nearly always utilized as parts of larger combatgroups. Their activities must, therefore, be coordinatedcarefully with those of tank, infantry, or other elements.Every engineer officer and noncommissioned officermust understand the characteristics of the other armswith which his command must function (paragraph 5).

b. The battalion commander should take every oppor-tunity for combined training of armored engineer troopswith the other elements of the division and with at-tached treadway bridge companies. Typical combinedproblems should be planned and executed, includingoperations which will allow the engineer battalion to-

(1) Reconnoiter and prepare routes for tank units inattack.

(2) Transport tank and other heavy units acrossstreams by means of ferries and floating bridges.

(3) Construct road blocks and mine fields for defenseby other units.

(4) Assist in the assault of field and permanent fortifi-cations.

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Section IV

RECONNAISSANCE

21. GENERAL. a. Reconnaissance by the armored en-gineer battalion consists of obtaining technical dataabout all terrain features which can have an importanteffect upon the mission of the battalion. This includesdetermination of-

(1) Type, load, capacity, and traffic capabilities ofroads, routes, and bridges.

(2) Location of and means of avoiding swamps, minefields, defiles, weak bridges, and other actual or poten-tial obstacles.

(3) Sites for construction of fords, bridges, and ferries.(4) Location, type, and quantity of materiel usable for

engineer or other supplies, This includes constructionmaterial, standing timber, water, fuel, lubricants, food,abandoned ammunition and vehicles.

b. Details of the methods of engineer reconnaissanceare given in FM 5-6.

22. OPERATIONS WITH RECONNAISSANCESQUADRON. a. Reconnaissance section. (1) The recon-naissance section of the engineer battalion headquarterscompany is attached normally to the division recon-naissance squadron, at least until contact is made withthe enemy. The mission of this attached section is to ob-tain information about the condition of routes for themain columns of the division. This includes investigationof important defiles and vital bridges previously knownto be key points, and general route reconnaissance of theentire terrain.

(2) Prompt transmission to engineer battalion head-quarters of the information gathered by the reconnais-sance section is a necessity. On this information depends

17

the performance of the mission of the battalion andhence the mobility of the division. These data must beavailable to the division engineer to indicate the properdisposition of engineer troops and supplies. Satisfactorydelivery of the information requires direct transmissionor prompt relaying by long range radio (see paragraph 8).

b. Attached working units. (1) To assure mobilityof the reconnaissance squadron it may be necessary toattach engineer troops to it. The size and dispositionof the attachment is dependent on such factors as theterrain, and the extent of enemy demolitions and minefield defenses. The attached unit is never smaller thana platoon, and may be as large as a company for opera-tions in rough country. All engineer squads receivetraining which fits them for work with reconnaissanceelements. Normally the first unit assigned to recon-naissance duty from an engineer company is the armoredplatoon, because of the mobility and protection affordedby its equipment (see paragraph 17b).

(2) Attached engineers assist the movement of re-connaissance elements by hasty repair of bridges, con-struction of fords and small ferries, and removal of ob-stacles. The commander of the attached unit recom-mends to the reconnaissance squadron commander amethod of employing his attached engineers, advises himof the condition of bridges and obstacles, and directsthe execution of the engineer tasks.

23. ENGINEER COMPANY RECONNAISSANCE.Engineer units attached to a combat command may de-tail personnel trained in reconnaissance to performspecific reconnaissance missions for the command. Themethod of operation of these detachments is similar tothat of the reconnaissance section of the headquarterscompany. Information secured is transmitted as quicklyas possible to the parent engineer unit. Information ofuse to the engineer battalion or combat command is re-layed promptly by the company commander.

18

24. ENGINEER SITUATION MAP. The assistantdivision engineer, at the forward echelon of divisionheadquarters, keeps an engineer situation map on whichis plotted pertinent engineer information, supplementedas necessary by tabular data (see paragraph 10b andfigure 10).

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24

Section V

MARCHES

25. CONDUCT OF MARCHES. See FM 25-10,and FM 17-50 for methods of conducting marches.

26. ENGINEER OPERATIONS. a. When thearmored division is on the march, the primary missionof the armored engineer battalion is to assist its pro-gress. To accomplish this, the battalion performs early,rapid, and complete reconnaissance, and effects neces-sary repairs to routes and bridges with a minimum ofdelay.

b. Engineers insure usable routes from railheads orprimary road nets, and from bivouac areas to assemblyareas. From assembly areas, routes may have to beprepared for the approach march.

25

Section VI

SECURITY

27. GENERAL. a. Security embraces all measurestaken for protection against surprise, observation, andinterference by the enemy. It includes special measurestaken for protection against hostile air, mechanized, andchemical attacks.

b. The security provisions covered in FM 100-5 andFM 5-5 apply generally to armored engineer troops.

c. The division plan for general security usually in-cludes some engineer devices and effort. These mayvary from a few hasty obstacles and the hasty mining ofbridges, to the connecting of natural barriers with a sys-tem of extensive artificial barriers in depth. The systemmay include antitank mines, personnel mines, bridge andford demolitions, abatis, craters, and improvised ob-stacles, all properly concealed. If other troops are notinitially charged with the defense of such devices, en-gineers cover the barriers by fire until relieved. En-gineers should be relieved from such duties by othertroops as soon as practicable in order to proceed onimportant engineer tasks. Engineers cannot properlydefend obstacles against heavily armored forces becausetheir armament includes no heavy caliber weapons.

d. Each engineer unit, regardless of size, is respon-sible for its own local security.

28. AT WORK. a. The security for a workinggroup may be provided by other troops. However, localsecurity remains the direct responsibility of the engineercommander, who utilizes his own troops for this purposeor satisfies himself that the local security measures be-ing taken by other troops are fully adequate.

b. Each engineer commander makes a plan of actionto be followed in case of enemy attack. This plan may

26

provide for reinforcement of security elements from theworking party, or for the withdrawal of working groupsunder the protection of security elements. Troops atwork always keep their weapons nearby, ready for in-stant use.

c. (1) Security against enemy ground action is pro-vided by an outpost. The location and nature of theoutposts are determined by the anticipated enemy threatand by the location of working parties. The strengthand composition of the outposts vary with the distance,mobility, and aggressiveness of the enemy, the time ofdav, the terrain, the size of the command to be pro-tected, the degree of resistance the outposts are ex-pected to offer, and any special duties assigned to them.Dispositions are no stronger than is consistent withreasonable security. Normally, small outguards of fromtwo men to a squad, equipped with suitable weaponsand posted on the principal avenues of approach, willprovide adequate security against enemy ground action.For full discussion of outpost see FM 7-10 and 17-42.

(2) Defenses normally include the planned use ofdismounted troops and vehicular or ground machineguns. Antitank mines may be used to block roads andother passages.

d. For security against chemicals see FM 21-40.29. ON THE MARCH. The extent to which an en-

gineer unit on the march provides for its security de-pends upon the measures taken by other troops in thesame column and upon the expectation of contact withthe enemy. Engineers are not used as general securityforces unless operating alone. An engineer unit oper-ating alone, however, provides for its security on themarch by forming advance, flank, and rear guards. (Forsecurity formations, see FM 17-42).

30. AGAINST AIR ATTACK. a. General. En-gineer units protect themselves against air attack by awarning system, dispersion, concealment, and night andcross-country marches. They take measures for imme-

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diate protection against low-flying aircraft by usingtheir own weapons which are suitable for fire againstaircraft. All troops charged with this duty are preparedconstantly for immediate action, but will fire only uponorder of an officer or responsible noncommissioned offi-cer. No aircraft will be fired upon unless it has beenclearly recognized as hostile or is positively identifiedas hostile, or attacks with bombs or gun fire.

b. Warning system. An aircraft warning systemmust be organized to provide timely warning of theapproach of hostile planes. Sentinels are posted at alltimes to warn of the approach of enemy aircraft. Inbivouac and at the halt, these sentinels should be postedin positions of good observation and are provided withadequate means of communication. Units should bealert for radio warnings over command channels. Anti-aircraft weapons are sited and manned habitually.

c. In bivouac. In bivouac, assembly areas, andrallying points, air security is obtained primarily byconcealment and dispersion. Enforce rigid camouflageand light discipline. Curtail use of fires to avoid dis-closure of positions by smoke. Brush out all vehiculartracks. Fox holes should be dug.

d. On the march. Density of vehicles usually doesnot exceed 20 to the mile if there is danger of air attack.Provision should be made for all around protection byfire. Be prepared to repel low-flying planes attackingfrom the direction of hills and woods. Use machinegun and effective small arms fire. Pistols, carbines, andsubmachine guns are not considered effective antiair-craft weapons.

31 DEFENSE OF KEY BRIDGES. a. Bridgeserected by engineers. When an important bridge, par-ticularly of treadway construction, is erected by en-gineer troops, provision is made for efficient defense ofthe structure, including defense against aircraft. En-gineers can effect some protection of such a bridge, butare normally made available for further engineer work

32

as soon as possible. Other troops in greater strengthand with heavier armament are usually required to de-fend the structure adequately.

b. Bridges prepared for demolition. In a retrogrademovement, bridges which are to be demolished areguarded against surprise and seizure intact by theenemy. Do not leave a prepared demolition unguarded.Bridges which are to be destroyed but which are stillof use to friendly troops are not blown prematurely.Such a bridge is secured from attack and seizure bysmall enemy forces, in order to be usable by friendlytroops as long as possible. This defense may be per-formed by forces varying from small engineer groupswhich prepare the demolition to infantry, antiaircraft,and tank destroyer units. (See paragraph 40). Definiteorders should be given as to when or under what cir-cumstances the bridge will be destroyed. A definitetime may be set or orders may be given that the bridgewill be destroyed when certain units are across. Thebridge should be destroyed if about to fall into enemyhands.

33

Figure 1.5. An inl)portant bridge is defended b!y heavilyarmed tro ops of adequate strength.

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Section VII

OFFENSIVE ACTION

32. GENERAL. Offensive action by armored unitsis covered in FM 100-5, FM 17-100, and other fieldmanuals.

a. The primary mission of engineers in offensiveaction is to assist the rapid movement of combatelements. Engineers build and reinforce bridges, andremove or make passages through mine fields and otherantitank obstacles.

b. Some engineer work can be foreseen, but duringbattle much unanticipated engineer work must be per-formed. Leaders of engineer units of all sizes are pre-pared to determine what engineer operations are neces-sary, and to execute them without specific instructionsfrom higher authorities. Use expedients. Don't builda bridge when a ford will carry the traffic. When pos-sible, have available standard equipage such as lumber,metal mats and treadways, but strive to save it forcritical needs by using local material. Take advantageof the mobility of armored units by using detours toeffect easy crossings and by-pass obstacles. Time is themost important factor in all such operations.

33. ASSEMBLY AREA OPERATIONS. a. To as-sist the movement of the division into the assembly area,engineers-

(1) Reconnoiter and report condition of all importantroutes (see Section IV).

(2) Remove obstacles on approach roads.(3) Improve fords, install and operate ferries, and

strengthen, repair, or construct bridges.(4) Provide security by use of demolitions and ob-

structions on flanks and in the rear.

38

Figure 19. Do not waste time by building an unnecessarybridge.

Figure 20. Save time by building a ford when it will carrythe traffic.

39

Figure 21. Use hand labor only when necessary.

Figure 22. Save time by having power equipment available.

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b. In the assembly area, engineers-(1) Operate water points.(2) Assemble engineer supplies and equipment

needed to support forthcoming operations.(3) Reconnoiter routes to the attack positions and

prepare plans for required work.(4) Perform work on routes to the attack position

when such action will not disclose our plans to theenemy.

c. In the approach march, engineers-(1) Prepare routes to the attack position.(2) Assist the advance beyond the attack position

by rapidly providing means for crossing or by-passingstreams, canals, marshes, gullies, antitank barriers, andsimilar obstacles.

(3) Remove or clear and mark lanes through minefields.

34. ACTION IN PURSUIT. In a pursuit, the suc-cess of the whole action may depend on the maintenanceof unobstructed routes for the tank elements. Engineertroops should be well forward, well supplied, and inample strength. They rapidly construct or repair ferriesand bridges, remove mine fields and other obstacles,seize bridges before they can be destroyed, and placehasty road blocks to retard and isolate enemy units.

35. ATTACK OF A FORTIFIED POSITION. a.When an attack on a fortified position by armored troopsis necessary, it should be performed by specially or-ganized assault units. These include infantry and en-gineers, supported by massed artillery and bombard-ment aviation. These special units should receive thor-ough advance training, including realistic rehearsalsagainst similar structures and areas to be assaulted (seeFM 100-5, FM 5-6, and FM 31-50).

b. Engineer operations in such actions consist ofclearing paths through barriers, and breaching wallsand destroying gun emplacements with explosives.

45

c. Similar tactics may be employed by engineers asa part of mopping up operations in cities and towns.Engineers assist in the clearing of such positions byusing explosives to breach street barricades and de-molish buildings.

36. ATTACK OF A STREAMLINE. The subject ofriver crossings is covered generally in FM 100-5, FM17-100, and FM 17-33. Engineer operations are dis-cussed in FM 5-5. Technical data on the treadwavbridge is found in TM 5-272.

a. General. Engineers are called upon to assist inall types of stream crossings. They construct ferriesand erect fixed and floating bridges. They may trans-port personnel in assault boats, pontons, or on im-provised rafts. In all operations they establish adequatesecurity, and use speed and deception to the utmost.

b. Initial information. Before a major stream iscrossed, data is gathered concerning the general con-dition of the river, and the condition and location oftributaries, bridge sites, and approaches. Reconnaissance,air photographs, and all other methods available areused to collect this information.

c. Equipment. When a river is to be spanned withassault boats, large ferries, or a floating bridge, neces-sary equipment is obtained from corps or higher units.Armored engineers normally effect such a crossing byusing steel treadway bridge equipment which is trans-ported and unloaded by an engineer bridge companyattached by the higher echelon. Plans are made tomove the bridge unit to the site of the operation, andto protect the site during and after the crossing.

d. Construction of treadway bridge. Line companiesof the armored engineer battalion construct the tread-way bridge. The strength of the various details is de--pendent on the size of the bridge, urgency of its con-struction, condition of the stream, and engineer re-quirements elsewhere. Use of several working points,often considerable distances apart, aids the effort by

46

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reducing size, confusion, and congestion of workinggroups, and improving chances for concealment. Inmany situations this method can be extended to effectmajor surprise of the enemy. Work on approaches tothe bridge site should be started as early as possible.Poor approaches often are the major delay in crossing astream. Portions of the bridge may be completed in con-cealment in tributaries or between islands and the shore,then moved into place rapidly with the help of powerboats or outboard motors. Often useful devices are theconcealment of the actual point of crossing with smoke,and the construction of dummy bridges of spare and im-provised material. Speed and deception should be used.

37. THE ATTACK. ,Armored units seek to attackby envelopment. When this is impracticable attack bypenetration is made through weak spots in the enemyposition. Attack against well organized positions ismade only when other operations are not practicable.The attack may be made with either infantry or tanksleading depending upon the terrain and the hostile de-fense (FMI 17-100). Engineers and infantry breach themine fields and reduce the obstacles so the tanks maypass through and continue the attack. When tanks lead,engineers must be well forward to assist tanks in tra-versing bad terrain and to move forward with the in-fantry should mine fields or other obstacles be en-countered.

38. ILLUSTRATIVE PROBLEM-ENGINEER OP-ERATIONS. In the sample situation below, it is as-sumed that an armored division is in a pursuit. Theenemy has organized a fairly strong position in terrainfavorable to him; attack in this sector is necessary asadjacent terrain is impassable. The armored division'sattack in this sector is designed to penetrate the enemyposition and allow tank units to reach the favorableterrain beyond. Typical engineer functions in this typeof penetration are shown.

48

I - RECONNAISSANCE OPERATIONS

(See figure 28)

GENERAL ACTION ENGINEEROPERATIONS

Division reconnaissanceelements (with 1 engineerreconnaissance section and Reconnaissance section1 engineer platoon at- reports condition of alltached) advance east along roads, bridges, and fordsmain highway until in area to combat com-stopped in Ufans by par- mand and engineer battal-tially destroyed bridge (2 ion headquarters.spans of I a r g e timberstructure are blown).

Reconnaissance sectionreports location of possible

Reconnaissance extends ferry site; natural construc-north and south of town. tion material available.Patrols attempt to cross Engineer platoon repairsr i v e r in reconnaissance ford and reinforces weakboats, encounter fire from truss bridge to take loadenemy infantry near site up through armored car onof blown bridge. secondary road southwest

of Ufans. (No heavier loadpossible here without re-placing bridge.)

Division reconnaissanceelements cross s t r e a msouthwest of Ufans, fightoff enemy patrols. Engineer platoon con-

Reconnaissance u n its structs ford southeast ofby-pass detachment of en- Ufans.emy infantry in town, butcannot penetrate enemydefenses in line of woodseast of Ufans.

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GENERAL ACTION ENGINEEROPERATION

Reinforced armored in-fantry battalion (with 1 Reconnaissance sectionplatoon of engineers at- reports estimates of mate-tached) acting as combat riel, equipment, and per-command advance guard sonnel needed to repairmarches east on route of bridge at Ufans. Decisiondivision reconnaissance. is made by combat com-Infantry takes up attack of mand commander to re-enemy defenses east of pair bridge. AdditionalUfans. Clears enemy out of construction material is as-Ufans. Supporting weap- signed to combat com-ons which cannot cross mand engineers by divi-weak bridge fire from west sion engineer.bank of stream, south of Advance guard engineerUfans. p 1 a t o o n improves and

maintains route southeastof Ufans, begins repair ofbridge at Ufans under pro-tection of infantry. Re-mainder of combat com-mand engineer companymoves forward from mainbody to bridge site.

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III - MAIN ATTACK

(See figure 30)

GENERAL ACTION ENGINEEROPERATION

Main body of combat During night, engineercommand, with 1 infantry company constructs newbattalion leading and in- section of timber bridge atcluding 1 artillery and 1 Ufans, reinforces structuretank battalion less advance to take medium tanks (8guard detachments, ad- hours).vances east. Infantry fol-lows route of advanceguard, drives back defenseline east of Ufans to hillsflanking mine field.

Tanks remain in assem-bly area west of Ufans.

IV - COMPLETION OF PENETRATION

(See figure 31)

GENERAL ACTION ENGINEEROPERATION

Artillery crosses river,places concentrations on E n g i n e e r companyweapons in hills north and leaves details to maintainsouth of mine field to as- route, displaces forward,sist infantry assault of reconnoiters and preparesmine field defenses. to breach mine field.

Infantry clears defensesof mine field with help ofartillery and fire of tanks. E n g i n e e r company

Some tanks assist infan- clears and marks lanestry by fire. All are ready to through mine field.pursue enemy when pass isclear.

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Section VIII

DEFENSIVE ACTION AND

RETROGRADE MOVEMENTS

39. GENERAL. Defensive action and retrogrademovements by armored units is covered in FM 100-5,FM 17-100 and other field manuals. Details of engineerfunctions in such operations are covered in FM 5-6.

40. OBSTACLES AND DEMOLITIONS. a. Bar-riers. Obstacle technique is covered in FM 5-30 andFM 5-31. When engineers construct or supervise con-struction of mine fields or other barriers on routes ofwithdrawal, they provide well marked lanes throughthe obstacle for the passage of friendly forces. Whena barrier has been crossed by all friendly troops, or isin imminent danger of assault by the enemy, existinggaps are closed. Usually all markings are removed, al-though in some cases they may be left to mislead theenemy. Booby traps may greatly retard the enemy, andshould be used extensively on barriers when the amountof time, personnel, and materiel permit. Provisions aremade for security of working troops and for defense ofcompleted obstacles (paragraph 27).

b. Demolitions. In a delaying action, all importantfords and bridges are prepared for demolition. Thosenot to be used by withdrawing or delaying troops aredestroyed; others are prepared and defended. A planof demolitions is prepared by the division engineer forapproval by the commanding general. Control of actualexecution of demolitions is decentralized. Responsi-bility for a demolition rests with the unit preparing it.

41. DEFENSIVE. In the defensive the armored di-vision usually is held in reserve. It may be forced to

56

take the defensive temporarily when acting alone. Rarelywill it be given a defensive sector to hold.

a. When the armored division is in reserve thearmored engineers prepare and keep open routes toprobable areas of employment. In the counterattackby the division, engineers operate as in the offensive.

b. When the armored division occupies a defensiveposition engineers prepare obstacles, lay mine fields,prepare and perform demolitions, and prepare routesfor counterattacking forces. Usually, some engineersare attached to the reconnaissance squadron or counter-reconnaissance force to destroy bridges and other fea-tures thus delaying the enemy. Infantry usually plansand fortifies the positions it occupies. However, in ex-ceptional circumstances, such as when infantry is en-gaged elsewhere, engineers may be used to lay out theposition, marking limiting points, and furnish guides formoving troops into position.

42. RETROGRADE MOVEMENTS. In retrogrademovements engineers perform demolitions, erect ob-stacles, plant mine fields, and keep open routes to therear.

57

BRIDGE PREPARED FOR BRIDGES BLOWN BYDEMOLITION BY REAR REAR ECHELON ENGINEERSECHELON ENGINEERS

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58

Figure 33. If pressed for time, do not use slow methodsof demolition.

Figure 34. If time is short, speed demolitions by allavailable means.

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Figure 36. Do not waste explosives when other means ofdemolition are practicable.

Figure 37. Economize on explosives by using expedients.This method is time consuming and often ineffective.

Destruction must be carefully checked.

61

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INDEX

Paragraphs Pages

Assistant division engineer _-___---_ 10, 13 11, 12Attachment __________________-__ 5 3Attack (see offensive action)Bridges

Construction __-__-_-____---_ 32, 36 3' 8, 46Defense _-__-_____________-- 31 32Equipment __-_____________-- 36 46False _-_______-___-_____ _-- 36 48Material _-_y________________ 9 7

Characteristics of vehicles _-_----__ Appendix 62Communication _____-_______---__ 8 3Deception in stream crossings __-__- 36 46Defense _-_-__________-- -____-__ 7, 28, 30, 31 3,26,27,32Defensive action ____________-_-__ 39-42 56Defensive ______________-__-_ 41 56Demolitions ______-_____-____--__ 40 56Division engineer _-________-_____ 10 11Duties

Assistant division engineer __-_ '10 11Division engineer _________-__ 10 11

Employment _________________-__ 4 2Engineer operations

In assembly area _______-__- __ 33 38In attack --_________________ 37, 38 48In attack of a fortified position _ 35 45In attack of a streamline ___-__ 36 46In defensive situations _____-__ 39-42 56On marches ______-_________- 26 25With reconnaissance squadron __ 22 17

Engineer situation map _______- - _ 24 19Explosives ____________-___-__-__ 9 10Liaison ____-_______-_______-____ 13 12Map

Engineer situation ________-__ 24 19Supply ___-________-_____-__ 9 7

Marches _-___________________-__ 25, 26 25

THE ARMY LIBRARY 65

WOINTON, . C.

Paragraphs Pages

Mission -_----------------------- 2 1Offensive action _-_3______ _ --- _ 32-38 38

Assembly area operations - -____ 33 38Attack _________-8_____-_____ 37, 38 48Attack of fortified position -__- 35 45Attack of streamline ___-__-_-- 36 46Pursuit --------------------- 34. 45

Orders ___…--_-- __-- _----------- 12 12Organization --------------------- 3 2Radio --_____.-- _--------------- 8 3Reconnaissance _-____-_________ 21-24 17

By attached companies -______ 23 18Map record of data ____-______ 24 19Transmission of data ________-- 22 17With reconnaissance squadron __ 22 17

SecurityAgainst air attack ------------ 30 27At work _____________-______ 28 26Key bridges _-__________-___- 31 32On the march ___-- __________ 29 27

Standing operating procedure ______ 12 12Supply _-___.___________________ 9 7Training

Battalion -__-_--.--- ___-___- 19 16Combined ____________-______ 20 16Company ____________--_____ 18 15Individual _-__--------_---- - 15 14Platoon ______________.-_____ 17 15Squad ---------------------- 16 14

Water supply ______-____________ 9 8

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