MHI

DEP,·IFM 20-22DEPARTMENT OF THE ARMY FIELD MANUAL

VEHICLERECOVERY

OPERATIONS

HEADQUARTERS, DEPARTMENT OF THE ARMY

JULY 1970

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*FM 20-22

FIELD MANUAL HEADQUARTERSI DEPARTMENT OF THE ARMY

No. 20-22) WASHINGTON, D.C., 80 July 1970

VEHOCLEA RECOVERY OPERATIONS

Paragraph Page

CHAPTER 1. INTRODUCTION 1-2 32. ORGANIZATIONAL

METHODS ANDLEVELS OF RE:COVERY --.----. 3-4 5

3. RECOVERY FUNDA-MENTALS

Section I. Resistance .... 5-7 7II. Sources of Effort -... 8-9 12

III. Basic Principles -------- 10-12 17IV. Application of Basic

Principles . 13-15 20CHAPTER 4. RIGGING FOR RECOV-

ERYSection I. Rigging Fundamentals'_ 16-21 27

II. Strength of Equipment_ 22-25 31III. Anchors ...... 26-28 36IV. Rigging Techniques -.-. 29-30 42V. Safety 31-44 48

CHAPTER 5. RECOVERY PRO-CEDURE 45-53 58

6. VEIICLE RECOVERYOPER \TIONS

Section I. Similar Vehicles ------- 54-58 63II. Recovery Expedients --- 56-69 72

III. Expedient Repairs --.--- 70-85 92

*This manual supersedes FM 20-22, 31 October 1962.

TAGO 3059C

Paragraph Page

IV. Special Purpose Ve-hicles _.-.--.-.... 86-94 108

CHAPTER 7. UNDERWATER VE-HICLE RECOVERY __ 95-100 122

APPENDIX A. REFERENCES -------- 130

2

CHAPTER I

INTRODUCTION

i. PurpUoe

To provide information and guidance for person-nel of all branches of the Army which will enablethem to recover vehicles disabled due to terrainconditions, enemy action, or mechanical malfunc-tions.

2. Scopea. This manual contains formulas and rules for

use in vehicle recovery operations. It covers meth-ods of determining resistances of vehicles dis-abled by terrain, and application of riggings andequipment to overcome these resistances. It coversexpedient repairs, recovery expedients, and safetyprecautions to be observed in vehicle recovery op-erations. The fundamentals are applicable with-out modification to both nuclear and nonnuclearwarfare.

b. Users of this manual are encouraged to sub-mit suggestions, changes, or comments to im-prove this manual. Comments should be keyed tothe specific page, paragraph, and line of the text.Reasons should be provided for each comment to

3

insure understanding and complete evaluation.Comments should be prepared using DA Form2028 (Recommended Changes to Publications)and forwarded direct to U.S. Army Armor School,ATTN: ATSAR-DMP, Fort Knox, Kentucky40121.

CHAPTER 2

ORGANIZATIONAL METHODS AND LEVELSOF RECOVERY

3. Methods of RecoveryThere are four methods of recovery that are per-formed using organizational personnel and equip-ment.

a. Winching. Operations performed usingwinches on special purpose vehicles or cargotype vehicles.

b. Towing. Operations performed using towingcapabilities of similar or special purpose vehicles.This is the quickest recovery method.

c. Lifting. Operations performed using specialpurpose vehicles.

d. Expedients. Used when other methods arenot adaptable to the situation or when additionalvehicles and equipment 'are not readily available.

4. Levels of RecoveryRecovery operations performed within an orga-nization are divided into levels. Levels are based

s

on personnel who perform the operations andequipment available to them.

a. Platoon Level. Recovery performed by ve-hicle drivers and crews, under supervision ofsquad, section, or platoon leader. At this level,winching, towing, and expedient methods ofrecovery are employed, using platoon vehiclesand equipment.

b. Company and Battalion Levels. Recoveryperformed by general vehicle repairmen or re-covery specialists under the supervision of therecovery chief, using winching, towing, and lift-ing methods of recovery with special purpose ve-hicles. Because of the increased number of specialpurpose vehicles at battalion level, a greater re-covery capability exists than at company level.

6

Seedon D. RESUSUAMCO

S. 'ypos e R@seziance in Recovery Opwraieonz

Resistance is any opposing force that tends to pre-· vent movement. Resistances that cause the mostconcern in recovery situations are the resistancescreated by vehicles disabled by terrain. The threetypes of resistance created by vehicles disabled byterrain conditions are: grade, overturning, andmire. Grade resistance is created when-a vehicleis moved up a slope, and is caused by the weightof the vehicle affected by gravity. Oyerturningresistance is that part of the weight of the ve-hicle that acts against the force exerted to bringit back on its wheels or tracks. Mire resistance iscreated due to contact of mud between variouscomponents of vehicles, such as wheels, tracks,axle or gear housings, or hull.

6. Estimating Resistance of Vehicles Disabled byTerrain

Recovery operations should be accomplished asquickly as possible within the limitation of safety.

7

Figure 1. Grade resistance.

EFFORT

1/2 VEHICLE WEIGHT

I t1/2 VEHICLE WEIGHT

Figure 2. Overturning resistance.

It is time-consuming and difficult to use a mathe-matical formula to determine a precise amount of

8

resistance for a recovery operation, therefore afast estimate of the resistance will be accurateenough in most instances.

a. Grade Resistance. The maximum resistancethat may be encountered on a grade, even if thegrade is vertical, is the disabled vehicle's weight.Grade resistance should be estimated as equal tothe vehicle weight (fig 1).

b. Overturning Resistance. Half the vehicleweight is the maximum that will ever be beyondthe center of gravity relative to the point wherethe force will be exerted to upright the vehicle.Overturned resistance should be estimated asequal to one-half the vehicle weight (fig 2).

c. Mire Resistance. A vehicle is mired when itis in mud and can no longer propel itself. Resist-ance is estimated depending on the depth to whichvehicle is mired (fig 3).

(1) Wheel depth. When a vehicle is mired ata depth up to the top of the road wheels (trackedvehicle) or wheels (wheeled vehicle), resistanceshould be estimated as equal to the vehicle'sweight.

(2) Fender depth. When a vehicle is miredat a depth above the top of the wheels up to butnot over the fenders, the resistance should be esti-mated as twice the vehicle's weight.

(3) Turret depth. When a vehicle is miredabove the fenders from the turret ring to the topof the turret (on a tank) or up on the hull(light tracked vehicles) or up on the cab (wheeledvehicles) the resistance should be estimated atthree times the vehicle weight.

9

WHEEL DEPTH

FENDER DEPTH

TURRET DEPTH - __

Figure 3. Mire resistance.

Note. If a cargo-type vehicle is mired, the cargoweight must be added to the vehicle weight when estimat-ing resistance. As an example: a cargo truck weighing 6tons is carrying 2 tons of cargo; at wheel depth the re-sistance should be estimated at 8 tons, fender depth 16tons, and cab depth 24 tons.

7. Resistance Reducing Factors

Load resistance of mired tracked vehicles is affect-ed by the situation and mechanical condition ofthe vehicle. In most mired situations, the vehiclecan be recovered in the direction opposite its origi-nal travel and estimated resistance will be re-duced. Power applied to tracks of a mired vehiclewill also reduce resistance. By maintaining asteady pull on a mired tracked vehicle, the resis-tance may be slowly reduced since water can seepbetween the mud and the bottom of the vehicle.

a. When a mired vehicle is pulled in the direc-tion opposite that of original travel, the trackspass through ruts the vehicle created going into

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Maximum Minimum

Figure 4. Maximum and minimum winch capacities.

the mire. This action of pulling it through its ownruts will reduce estimated resistance approxi-mately 10 percent. As an example: a 50-tank ismired at wheel depth and can be recovered in theopposite direction of travel. Estimated resistanceof 50 tons (para 6c(1)) less 10 percent equals 45tons load resistance.

b. If power is applied to the tracks of a miredvehicle, the movement of tracks will assist inbreaking the suction of mud against the belly ofthe vehicle and cause resistance to be reduced ap-proximately 40 percent. As an example: a 50-tontank is mired at fender depth and must be re-covered in direction of travel. Estimated resis-tance of 100 tons (para 6c(2)) less 40 percentequals 60 tons load resistance.

c. If both reducing factors are applicable, resis-tance will be reduced 50 percent.

Note. Reducing factors of mired vehicles are not ap-plicable to wheeled vehicles. When trying to apply themto wheeled vehicles, the amount of reduction is so variable(due to lack of traction) their application cannot be re-lied upon; however, power applied to the wheels mayreduce resistance.

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Section II. SOURCE OF EFFORT

8. Source of Effort-Similar Vehicles

The most readily available source of recovery ef-fort at platoon level is the towing effort that canbe exerted by using similar vehicles. The averagevehicle can exert a force equal to its own weight inreverse gear, while on dry, level hardstafid. Re-verse gear normally provides the greatest gearreduction and affords the driver of the recoveryvehicle the greatest visibility. The towing capa-bility of any vehicle is affected by the type or con-dition of the terrain on which it is operating, thustwo or more vehicles may be required to exert aforce that one vehicle could exert under ideal con-ditions.

9. Sources of Effort-Winches

Even though the similar vehicle towing methodis normally the quickest means of recovery, thereare situations that do not permit its use. In suchsituations, a winch may be used. A typical situa-tion dictating use of a winch is one in which ap-proaches to the disabled vehicle do not providenecessary traction for towing vehicles. A winchprovides a more positive source of effort in thiscase, as its capacity is not dependent upon terrainconditions.

a. A winch can exert the greatest force or at-tain its maximum capacity only when pulling bythe first layer of cable on the winch drum or thatlayer of cable next to the bare winch drum. Aseach successive layer of cable is wound onto the

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Table 1. Winch Variable Capacities(Ordnance Winch, Gar Wood Industries)

Winch Cable Cable on Drum CapacityType Layer (ft.) (lb.)

10,000 1 0 - 39 10,000lb. 2 40 - 85 8,450

3 86 - 138 7,3404 139 - 199 6,460_5 200 - 266 5,780

20,000 1 0 - 41 20,000lb. 2 42 - 91 16,900

3 92 - 148 14,5004 149 - 213 12,8005 214- 287 11,400

45,000 1 0 - 42 45,000lb. 2 43 - 93 37,700

3 94- 153 32,5004 154- 220 28,5005 221 - 296 25,3006 297 - 380 22,800

60,000* 1 0 - 55 60,000lb. 2 56- 128 52,000

3 129 - 208 46,0004 209 - 300 40,000

90,000* 1 0 - 41 90,000lb. 2 42 - 91 76,000

3 92 - 149 65,0004 150 - 215 57,000

* Low gear

winch drum, the drum diameter increases andwinch capacity decreases (fig 4 and table 1). Itis desirable to unreel all or most of the cable fromthe winch drum when it is being used to winchheavy loads. However, several turns of the cable

13

DRUMCENTERLINE

FLEET

d} , XANGLE

,,20

Figure 5. Correct fleet angle.

14

DRUMCENTERLINE

N \ FLEET ANGLE GREATERTHAN 20

Figure 6. Incorrect fleet angle.

should remain on the winch drum. Another ad-vantage is gained by using the full length of cable,

15

Figure 7. Wench mechanical advantage.

because its natural elasticity or stretch preventsthe cable from breaking so readily in instanceswhere sudden impact loads are applied.

b. Ideally, the winch cable should be used insuch a manner that a line drawn through thelength of cable will continue through the centerline of the winching vehicle. Any deflection fromthis line is called fleet angle (fig 5) and is a very

16

important consideration in winching operations,particularly when the winch is not equipped witha level winding device. If the fleet angle is greaterthan 2°, the cable will lead to one side of thewinch drum, reducing winch capacity and possiblydamaging the cable (fig 6).

Note. For reference relative to operation of variouswinch types, refer to pertinent technical manuals.

Section Off. BASDC PIRBCIPLES

0. Iffort Versus Resistsance

The application of effort to overcome resistancehas been a challenge to man since the beginningof civilization. Modern machinery is illustrativeof the progress made in this field. Energy releasedby the burning of a small amount of gasoline inan engine provides the effort required to move anautomobile weighing thousands of pounds. Theautomobile engine is able with the assistance ofvarious mechanical devices to drive the vehiclefrom a static position throughout a wide range ofvarying speeds.

11. Mechanical Advantage

The devices built into thle automobile providemechanical advantage. Many applications aremade of mechanical advantage as power is trans-mitted from the engine to the vehicle's wheels;as an example, the gears of the transmission.There are many common applications of mechani-cal advantage by which every day work is per-formed. Common hand tools provide a mechanical

17

E= 4 FEET

2 FEET

R = 2 FEET

1iOT \ FULCRM

I //

RESISTANCE

Figure 8. Leverage principle.

advantage to assist the user in performing his taskA mechanical advantage is a small amount offorce applied over a long distance to move a greatload a short distance (fig 7). Mechanical advan-tage is the multiplication of force.

12. Leverage

a. Leverage Principle. A wrench handle, a canopener, and gears of an automobile gain a me-chanical advantage through the leverage principle.The simplest form of a lever is a rigid bar freeto turn on a fixed pivot called a fulcrum. When

RESISTANCE EFFORT

R E /

Figure 9. First class lever.

effort is exerted on one end of the bar, the barwill rotate around the fulcrum. A resistance ap-plied to the other end of the bar opposes the effortand tends to cause the bar to rotate in the oppositedirection. The part of the bar between the fulcrumand the point on the bar where the effort is ap-plied is called the effort distance or (E); thit partof the bar between the fulcrum and the pointwhere resistance is applied is called resistancedistance or (R). Mechanical advantage (MA)gained with a simple lever is determined by di-viding effort distance by resistance distance

(E= MA). As an example: In figure 8, R = 2

E 4 2 to MA. Thefeet, E = 4 feet. E 4 2 to 1 MA. Themovement distance of the effort, with relationto distance resistance is moved, is the same as

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mechanical advantage radio. Effort must move 2feet to move resistance 1 foot.

b. Lever Classification. Levers are divided in-to two classes. The class of lever is determinedby the location of the fulcrum with relation toeffort and resistance.

(1) A first-class lever has the fulcrum locatedbetween effort and resistance as illustrated infigure 9. A pair of pliers is a good example of afirst class lever.

(2) A second-class lever has the point of re-sistance between the fulcrum and the effort as il-lustrated in figure 10. A wheelbarrow is a goodexample of a second-class lever.

Section IV. APPLICATION OF BASIC PRINCIPLES

13. Tackle

Tackle is a combination of ropes and blocks usedto gain a mechanical advantage or to change direc-tion of pull. Tackle is classified as simple or com-pound.

a. Simple tackle consists of only one rope withone or more blocks (fig 11).

b. Compound tackle consists of more than onerope used with two or more blocks. It is a seriesof two or more simple tackles; wherein the outputof one simple tackle is used as the effort for theother (fig 12). Since a winch has only one cable,simple tackle will nearly always be used duringrecovery operations.

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-r

FULCRUM 2 FEET L

IRESISTANC 6 INCHES

E =6 FT R= 2 FT E =6 =3 TO 1 MA

LOAD

FULCRURT

FULCRUM

Figure 10. Second-class lever.

14. Blocks, Types by Construction

Blocks consist of a shell or frame in which ismounted one or more grooved wheels calledsheaves. The sheaves are mounted on a pin that issupported by the shell. The shell also has a meansof attaching the block to a load or to an anchor

21

A

CH0R

Figure 12. Simple tackle.

A. Conventional Block. A conventional block is

C Nused with C0 HR 0

R

Figure 12. Compound tackle.

(fig 13). Blocks with one or two sheaves are re-ferred to as single or double sheave blocks. Blocksare typed according to their construction.

a. Conventional Block. A conventional block isused with fiber rope. To form a tackle with con-ventionaltch blocks, the blocks are laid out and therope must be reeved or threaded through theblocks (fig 14).

b. Snatch Block. Since winch cables have at-tachments on their free ends, such as hooks orsockets, they cannot be reeved through a block. Asnatch block is constructed so the shell can beopened at the base of its attachment to admit acable without reeving (fig 15).

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SHEAVEPIN

SHELL

SHEAVE

Figure 13. Block components.

Figure 14. Conventional block.

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Figure 15. Snatch block.

A 1 IS A SPINNING LEVER

Figure 16. Spinning lever.

15. Blocks, Classification by Usage

The sheave of a block functions as a lever. It per-forms this function more efficiently than a simplebar lever by providing a continuous lever action,without the necessity of repositioning each timeit has moved through its arc. In effect a sheave isa spinning lever (fig 16).

a. Fixed Block. A block attached to a stationaryobject (anchor) is classified as a fixed block. Thesheave of a fixed block permits a change in direc-

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LOAD

Figure 17. Fixed block.

LOAD

Figure 18. Running block.

lFALL LINE

RETURN LINES

DEAD LINES LOAD

DEAD LINE

Figure 19. Tackle terminology.

tion of the rope and functions as a first-class leverbecause the rope enters one side of the sheavefrom the source of effort, passes around the sheaveand returns to the resistance. The sheave pin isthe fulcrum, and the distance from the pin to oneside of the sheave is equal to the distance fromthe pin to the opposite side, therefore effort dis-tance (E) and resistance (R) are equal; no me-chanical advantage is gained (fig 17).

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b. Running Block. A block that is attached tothe load and moves with the load is classified as arunning block. A running block will always gaina mechanical advantage, and its sheave functionsas a second-class lever. The sheave is reeved in thesame manner as the fixed block, however, theload location is on the sheave pin; the fulcrumis at one side of the sheave and the effort is exertedon the opposite side. The resistance distance (R)is from the pin to one side of the sheave (radiusof the sheave). Effort distance (E) is from oneside of the sheave to the opposite side (sheavediameter). Effort distance is twice resistance dis-tance; the mechanical advantage is 2 to 1 (fig 18).

c. Floating Block. A block used with a tow cableto allow the pull of the cable to aline with thesource of power is known as a floating block. Afloating block provides no mechanical advantage.It allows the pull to be equally distributed to bothtow attachments (hooks) of the disabled vehicle(fig 35).

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CHAPTER 4

RIGGING FOR RECOVERY

Section I. RIGGING FUNDAMENTALS

16. Rigging

Rigging is the application of fiber or wire rope invarious tackle combinations used to raise or moveloads; Rigging includes installation of all items ofequipment necessary to employ the effort availableand may or may not produce a mechanical advan-tage. The various parts of a tackle are illustratedin figure 19.

a. Fall Line. The line from the source of effortto the first block in the tackle is the fall line.There is only one fall line in a simple tackle sys-tem.

b. Return Lines. The lines between the blocksor the line from the sheave of a block to the pointwhere the end of the line is attached are returnlines.

c. Dead Lines. The lines used to attach blocksor other equipment to the load or to an anchorare dead lines.

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LOAD

LOAD

LOAD

LOAD

LOAD

5:1

Figure 20. Vaious tackle mechanecal advantages.

17. Mechanical Advantage of Tackle

a. As previously stated, a need for a mechanicaladvantage exists whenever the load resistance ex-ceeds the capacity of the available effort. The a-mount of mechanical advantage needed is esti-mated by dividing the load resistance by the effort.

b. The mechanical advantage (MA) of anysimple tackle rigging is equal to the number oflines supporting the load, or number of lines thatbecome shorter as power is applied to the winch,

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10,000 LBS CAPACITY FIRSTWINCH DEADLINE

39,000 LBS

9,750 LBS 30,000

\19,500 LBSTHIRD

DEADLINE9,750 LBS

Figure 21. Distribution of line forces.

whether the lines are attached directly or indirect-ly through a block (fig 20).

18. Tackle Resistance

Due to friction created by a sheave rotating on itspin, flexing of the rope around the sheave, andthe rope scuffing in the groove of the sheave, thereis a loss in energy as the rope passes around thesheave. This loss is considered as resistance be-cause it must be overcome before the resistanceof the load can be overcome. Each sheave in therigging will create resistance. The rule to deter-mine tackle resistance is: 10 percent of the loadresistance times the number of sheaves (notblocks) in the rigging. As an example, a load re-sistance of 30,000 pounds and a tackle with 3sheaves is being used, 10 percent of 30,000 poundsequals 3,000 pounds, times 3 (3 sheaves) equals9,000 pounds tackle resistance.

19. Total Resistance

The tackle resistance must be overcome beforethe load resistance can be moved, therefore, thetackle resistance must be added to the load resis-tance. This resistance is referred to as total resis-tance (the total amount of resistance that mustbe overcome by the available effort). Using theexample given in the preceeding paragraph ontackle resistance, the load resistance of 30,000pounds plus the tackle resistance of 9,000 poundsequals 39,000 pounds total resistance.

20. Fall Line Force

The amount of force that must be exerted on thefall line relative to the effort available must beconsidered in every problem. To determine the fallline force, divide the total resistance by the me-chanical advantage of the tackle. The fall lineforce must be less than the capacity of the effortto accomplish the recovery. For example, a 39,000pound total resistance to be overcome with aneffort of 10,000 pounds using a 4 to 1 mechanicaladvantage tackle. 39,000 pounds divided by 4 (4to 1 MA) equals 9,750 pounds fall line force.9,750 pounds fall line force is less than the effortof 10,000 pounds, the mechanical advantage is cor-rect for the recovery.

21. Dead Line Force

Dead lines in most cases must withstand moreforce than other lines in a tackle rigging. To de-termine dead line force, multiply the fall line forceby the number of lines supported by the dead

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line. From figure 21 and the fall line force of9,750 pounds the dead line forces are determinedas follows:

a. The first dead line is the sling attachment ofa double sheave block to the load. There are 4lines (the fall line and 3 return lines) supportedby the dead line through the block. 4 times (fallline force) 9,750 pounds equals 39,000 pounds onthe dead line.

b. The second dead line is used to attach a singlesheave block to an anchor, and is supporting tworeturn lines; two times 9,750 pounds equals 19,500pounds.

c. The third dead line is supporting only one re-turn line, therefore the third dead line is equalto the fall line force (9,750 pounds).

Section II. STRENGTH OF EQUIPMENT

22. Equipment Strength

Strength is the ability to resist force, or the cap-ability of a body to endure the application of force.Ropes and chains have strength, according to theirsize and the material from which they are made,to endure the application of a certain amount offorce without breaking.

23. Fiber Rope

Fiber rope may be used in recovery of relativelylight loads. The strength of a fiber rope will varyafter it has been used, has been wet, or if dirthas collected between the strands. The strength ofa new fiber rope can be determined by using the

31

I

II

Figure eP. Measurement of chain diameter.~~~~~32~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

Table 2. Rope and Chain Capacities

DIAMETER FIBER ROPE (sisal) WIRE ROPE (IPS) AND CHAIN(inches) T = 4D

2 (tons) T = 40D 2 (tons)

3/8 .5625 5.6257/16 .765625 7.656251/2 1. 10.5/8 1.5625 15.6253/4 2.25 22.57/8 3.0625 30.625

1 4. 40.1-1/8 5.0625 50.6251-1/4 6.25 62.51-1/2 9.0 90.

Table 3. Sling Leg Forces

Force per sling leg (2-leg slings) per 1,000 lb. of total resistance.

INCLUDED SLING LEG INCLUDED SLING LEGANGLE FORCE ANGLE FORCE

(degrees) (pounds) (degrees) (pounds)

0 500 90 70710 502 100 77820 508 110 87230 518 120 1,00040 532 130 1,18350 552 140 1,46260 577 150 1,93270 610 160 2,88080 653 170 5,734

formula T = 4D 2. This formula is based on theweakest fiber used to make rope. The T equalsthe capacity in tons; D equals the diameter of

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SLING LEG FORCE 18,288 LBS

36,000 LBS

SLING LEG CAPACITY (1/2-INCH(10 TONS) 20,000 LBS

Figure 23. Chain sling to anchor.

Figure 24. 1-1-1 combination picket holdfast.

Figure 25. $-2-1 combination picket holdfast.

the rope in inches. Therefore, when computingthe strength of a 1/2-inch rope, T = 4 x (1/2 x1/2) = 4 x 1/4 = 1 ton. For a 1 inch rope, T =4 x (1 x 1) = 4 x 1 = 4 tons.

24. Wire Rope and Chain

Wire rope is used for winch cables and tow cables.

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A wire rope may be constructed with either afiber rope or a wire rope core. A wire rope with awire rope core is stronger. The formula used to de-termine strength is based on wire rope made ofimproved plow steel (IPS) with a fiber rope core.The formula used is T= 40D 2. As with fiber rope,T equals the strength in tons; D the diameter ofthe rope in inches. In most instances where thediameter of the rope is stated in fractions of aninch, it is easier to convert the fraction to adecimal equivalent before computation. As an ex-ample, when computing the strength of a 5/8-inchwire rope, T = 40 x (5/8 x (5/8) or 40 (.625 x.625) = .390625 x 40 = 15.625 tons. The strengthof chain is determined using the same formulaas for wire rope. The diameter of a chain is thediameter of the stock from which the chain linksare made (fig 22). The strength of various sizesof ropes and chains are shown in table 2.

25. Sling Leg ForcesIn most recovery operations involving winchingor lifting a sling is used as a dead line. Slingsare usually made of chains or tow cables. Theholding ability of a sling attachment depends up-on the strength of the material of which the slingis made and the included angle of the sling. Theholding ability of a sling can be almost double thestrength of the material of which the sling ismade. As an example: A 1/2-inch diameter chainsling with an included angle of 200 is used to sup-port a force of 36,000 pounds. For each 1,000pounds of force imposed on the apex of the sling,

35

will result in 508 pounds of force imposed on eachsling leg as illustrated in table 3. Therefore,36(36,000 + 1,000) x 508 = 18,288 pounds im-posed force on each sling leg (fig 23). Note intable 3 that the sling leg force will increase withthe included angle of the sling.

Section III. ANCHORS

26. Use of Anchors

Frequently it is necessary to have some anchoringmeans when heavy loads must be moved withtackle. It is necessary at times to have an anchorassist in holding a winching vehicle, support partof the load during a winching operation, or pro-vide an anchor for a change of direction pull.

27. Natural Anchors

An anchor that does not have to be constructed isconsidered a natural anchor, such as trees, treestumps, large rocks, or another vehicle. Avoid deador rotten trees or tree stumps as their anchoringability cannot be relied upon. Examine rocks care-fully to ensure they are large enough and embed-ded firmly in the ground.

28. Mechanical Anchors

There are several types of anchors. The types con-structed depends upon the holding ability require-ments, type of soil, availability of materials, andthe situation.

a. Picket Holdfast. To construct a picket hold-fast, obtain two or more sound wooden pickets at

36

least 3 inches in diameter and 5 feet long. Drivethe pickets about 3 feet into the ground, 3 to 6feet apart and in line with the dead line. Tie thepickets together with fiber rope by first tying oneend of the rope to the top of the front picket witha clove hitch, and make four to six wraps of therope starting from the top of the front picket tothe bottom of the rear picket. Finally, tie theother end of the rope to the bottom of the rearpicket with a clove hitch. Pass a stake betweenrope wraps midway between the pickets, tightenthe rope by twisting it with the stake, then drivethe stake into the ground. Repeat this operationfor each successive pair of pickets (fig 24).The strength of the holdfast depends mainly onthe first or front picket. To reinforce the frontpicket, drive two or more pickets into the groundclose to the front picket, and tie them togetherbefore tying to the rear picket (fig 25).

b. Log-Picket Holdfast. For heavier loads insoft or wet earth, the combination log-picket hold-fast may be used. With this holdfast, one mustfasten the anchor or dead line to a timber support-ed against several (4-6) picket holdfasts (fig 26).The strength of this type of holdfast depends uponthe strength of the log, soil, and pickets. There-fore, select a timber strong e-.ough to withstandthe maximum pull on the dead line without bend-ing.

c. Log Dead Man. A dead man is one of thebest types of anchor for heavy loads. The deadman consists of a log buried in the ground withthe dead line connected to its center. When con-

37

Figure 26. Log-picket holdfast.

Figure 27. Log dead man.

Figure 28. Sand parachute.

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Figure 29. Sand parachute dead man.

structing a dead man, place it where the direc-tion of pull is as nearly horizontal as possible.Take advantage of sharp banks or crests to in-crease the holding power with less digging. Dig ahole large enough for the dead man and as deep asnecessary for good bearing. When digging the holeslant it in the direction of the pull at an angle ofabout 15 ° from the vertical. To strengthen the an-chor, drive stakes in front of the dead man at eachend. Dig a narrow inclined trench for the dead lineto the center of the dead man. Tie the dead line tothe center of the dead man so the main or stand-ing part of the line leads from the bottom of thedead man. This prevents the dead man from rota-ting out of the hole. If the dead line has a tendencyto cut into the ground, place a small log under theline at the outlet of the trench. A log dead man isillustrated in figure 27. The strength of the deadman depends on the strength of the log and theholding power of the earth.

39

d. Sand Parachute. In sandy area with no trees,a sand parachute may be used as an anchor. Asand parachute is constructed by digging a large,deep hole and lining it with a tarpaulin. The tar-paulin is then filled with the sand removed fromthe hole, the four corners of the tarpaulin arelashed together, and the rigging is attached. Thesand parachute is illustrated in figure 28.

e. Sand Parachute Dead Man. The sand para-chute dead man may be constructed in a similarmanner as the sand parachute, however, after thehole is dug, a spare tire is placed in the hole. Thedead line is secured to the fire, the tarpaulin em-placed, and the hole refilled. The corners of thetarpaulin are not drawn together. Figure 29 illu-strates a sand parachute dead man.

Note. The sand parachute and the sand parachutedead man have limited holding ability and should not beused when a major effort is required.

f. Scotch Anchor.(1) A scotch anchor is used to anchor a truck

during winching operations when natural anchorsare not available. To construct a scotch anchor,select a log at least 6 inches in diameter and 10inches longer than the tread width of the vehicle'sfront wheels. Dig a shallow trench about 3 or 4inches deep parallel to the front axle, just aheadof the front wheels. Lay a tow chain across thecenter of the trench, place the log in the trench,move the vehicle forward until both front tiresare against the log, and then attach both chainends to the vehicle's lifting shackles, removingall the slack from the chain. As power is applied

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4 =

Figure 30. Scotch anchor.

Figure 31. Backup method of rigging.

Figure 32. Lead method of rigging.

to the winch, the front wheels will be pulled ontothe log making the chain taut and anchoring thevehicle (A, fig 30).

(2) If two chains are available, a similarmethod may be used as follows: Lay two towchains across the trench next to the inside of eachfront wheel, place the log in the trench, move thevehicle forward until both front tires are againstthe log, and then wrap the chains through the lift-ing shackles, remove slack from the chain andfasten them together (B, fig 30).

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g. Vehicle Anchor. A vehicle may be used as ananchor to assist in recovering another vehicleequipped with a winch. The winch cable is extend-ed to the anchoring vehicle and the mired ve-hicle winches itself out. The anchor vehicle shouldnot attempt to pull the mired vehicle using themired vehicle's winch, but should remain only asan anchor. This will eliminate the possibility ofdamage to the winch.

Section IV. RIGGING TECHNIQUES

29. Methods of Rigging

The rigging method depends on the type of winch-ing vehicle and the distance between the winchingvehicle and load.

a. Manpower Method. The manpower methodof rigging is used when permitted by the size andweight of the equipment. If the winch cables andother rigging equipment are light weight, and canbe carried by the crew members with comparativeease to where it is needed, this method is the mostexpedient.

b. Backup Method. If the recovery vehicle canbe safety positioned within 20 to 25 feet of thedisabled vehicle, the backup method of riggingshould be used. The recovery crewmen pull outsufficient main winch cable to attach the cable tothe recovery vehicle; place the main winch snatchblock in the loop of the cable, close the block andattach the block to the object of recovery. Thedotted outline in figure 31 shows the recovery ve-hicle and the rigging attached to the disabled

42

Figure 33. Chain slings to lifting shackles.

43

6 FT.

SLING

Figure 84. Sling arrangement.

vehicle. The recovery vehicle is then backed up,allowing the main winch cable to be spooled fromthe winch drum until sufficient cable is removedto obtain maximum winch capacity. The solidlines in figure 31 show the recovery vehicle inposition to perform the winching operation.

#'/

Figure 35. Floating block.

Figure 36. Tow cable attachment.

c. Lead Method. If, because of terrain condi-tions, the recovery vehicle cannot be safely posi-tioned close to the object of recovery, the leadmethod of rigging should be used. The lead method

45

consists of using the hoist winch to lead the mainwinch rigging to the object of recovery. The hoistwinch cable weighs less than the main winchcable and can be carried to the object of recovery.To rig for the lead method, the main winch tackleis assembled just in front of the recovery vehicleas in preparation for the backup method. Thehoist winch cable end is attached to the mainwinch tackle snatch block, then the loop formedby the hoist winch cable is manually pulled outand placed into a snatch block attached to thedisabled vehicle. This application of the hoistwinch cable will provide a change of direction ofpull and by paying in hoist winch cable, the mainwinch tackle will be pulled to the object of re-covery. In figure 32, the dotted line indicates themain winch tackle erected at the front of the re-covery vehicle with the return line of the hoistwinch attached. The solid lines indicate the mainwinch tackle after it has been led to the disabledvehicle.

30. Methods of Attachment of TackleIn recovery operations, it is important that thetackle be rigged to the vehicle in such a manneras to prevent further damage to the vehicle orequipment. As an example, in recovery of a miredwheeled vehicle, the effort line should be attachedto the lifting shackles on both sides. It the pullingforce is attached only to one frame member, itcould be pulled out of alinement.

a. Wheeled Vehicle. On wheeled vehicles,whether the pull is made from the front or rear,

the effort should be applied to both front or rearlifting shackles, or the pintle hood.

Caution/ Pull on pintle hook should notexceed that which is specified by TM. The lift-ing shackles are designed to withstand forcefrom a horizontal or a vertical pull. To applythe effort equally to both shackles, a sling at-tachment must be used (fig 33).The most available item of equipment on wheeledvehicles is a tow or utility chain. The force ex-erted on each leg of the sling will be slightlygreater than half the resistance. A 12-foot chainattached in this manner on most wheeled vehicleswill form a sling with the apex of the sling ap-proximately 6 feet from the bumper with anincluded angle of about 30° (fig 34).

b. Tracked Vehicles. When attaching riggingsto tracked vehicles, always attach to the towinghooks or lugs. The lifting eyes and towing pintleare not designed to withstand the pulling forcerequired for recovery. To prevent pulling the ve-hicle sideways and increasing the resistance, usean attachment that will distribute the appliedforce to each side of the vehicle. If the vehiclewill require towing after winching, time can besaved by using the same attachment for winch-ing as for towing.

(1) When a disabled vehicle will not requiretowing and the resistance is such that a mechani-cal advantage is not required, the main winchsnatch block can be used with one tow cable toform a floating block hookup. This hookup is easyto install and will give an even distribution of the

47

effort to both tow hooks. To rig a floating block,attach the ends of the tow cable to the two towhooks; place the snatch block in the loop formedby the tow cable, and attach the winch cable tothe snatch block (fig 35).

(2) When a disabled vehicle requires a 2 to1 mechanical advantage rigging, and may requiretowing over rough terrain after winching, twotow cables are used to make the attachment asillustrated in figure 36. This attachment is thebest method, because it is the quickest to rig.

(3) When a vehicle must be towed over re-latively level terrain or on the highway afterwinching, the tow bar method of attachmentshould be used. The tow bar is attached to thetow lugs of the disabled vehicle and the winchrigging attached to the lunette of the tow bar(fig 37). After winching the rigging should bedisassembled and the tow bar lunette placed inthe recovery vehicle tow pintle (fig 37).

(4) If a 3 to 1 mechanical advantage is used,the running block is attached to one of the tow-ing lugs on the disabled vehicle, the change ofdirection block is attached to the dead man onthe recovery vehicle and the end of the winchcable is attached to the other towing lug on thedisabled vehicle (fig 38).

Section V. SAFETY

31. Safety

A successful recovery operation is one that is ac-complished quickly and safely. The preceding

48

Figure 37. Tow bar attachment.

paragraphs on fundamentals and the techniquesof rigging for recovery were to provide informa-tion and guidance to accomplish recovery quickly.To accomplish recovery safely, maximum caremust be taken during the erection and applica-tion of equipment to prevent damage to the ve-hicles and equipment, and injury to personnel.

32. Handling Cables

Cables or wire ropes may become damagedthrough use. The wires that make up the strandsof the rope may break. Personnel handling wireropes should wear heavy leather-palmed gloves toprevent hand injuries or cuts from broken wires.A moving cable should never be allowed to slidethrough the hand even when gloves are worn; abroken wire could cut through the glove.

33. Care of Cables

Care must be taken to prevent damage to cables

49

Figure 38. 3 to 1 mechanical advantage.

during use. Cables or ropes should not be drawnover rocks, around sharp corners, or through

50

Figure 40. Hook position.

sheaves that are designed for larger or smallercables. Never drop a heavy object on a wire rope,it could nick or burr the wires and cause them tobreak. All loops formed in a cable should be re-moved while the cable is slack and before anyforce is applied. Force applied to a looped wirerope will cause a kink, the strands will separateor break, and the rope will be weakened (fig 39).

34. Hook Position

A hook used in rigging should be positioned withthe open part (throat) upward (A, fig 40). If thehook should straighten out from overload, thetendency will be for the rigging to be forceddownward. If the hook were positioned with theopen part (throat) down, the rigging could travelupward unrestrained (B, fig 40).

35. Safety Keys

a. Safety keys should be in place on all towhooks, shackles, or other items of equipment re-

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A. CORRECT B. INCORRECT

Figure 41. Safety keys and shackle pins.

52

Figure 42. Crossed lines.

quiring them. Even though the safety key sup-ports no appreciable load, its absence can allowa pin to move, placing an excessive force on onlya part of a connection. Some shackles use athreaded type pin, and if the pin is not com-pletely threaded into the shackle part, the shackleor pin can be bent or broken when force is ap-plied (fig 41).

b. When using pins with safety keys, such asthe type in tow bars, all pins in a vertical planeshould have their heads pointing up. Then, evenif the safety key should break or fall out, the pinwill remain in position if the load shifts.

36. Rigiglng Between ®Vehicles

When erecting rigging between vehicles, enginesshould be off and vehicle brakes applied to pre-vent possible injury to the rigging personnel ordamage to the vehicles, except when erectingriggings using a recovery vehicle the engine must

UNSAFE AREA

A. TWO FARTHEST APART RIGGING POINTS.B. ANGLE OF PULL.

Figure 45. Unsafe areas.

be running to operate the equipment. To preventinjury to personnel or damage to equipment, therecovery vehicle brakes must be applied and thespade or chocks (wheeled vehicle) positioned toprevent movement.

37. Inspecting Rigged Equipment

Equipment should be thoroughly inspected beforethe recovery operation starts. The recovery ve-

54

hicle operator should be directed to apply powerto the winch and remove the slack from the rig-ging, then stop the operation so the rigging canbe inspected without endangering the personnel.

38. Crossed LinesIf the inspection reveals that the rigging linesare crossing each other, this condition must becorrected before the winching operation is con-tinued. It is possible that crossed rigging lineswill rub against each other, causing damage tothe cable or an increased amoung of tackle re-sistance (fig 42). Crossed cables are only recom-mended for towing a disabled vehicle.

39. Fuel or Oil Spillage

If fuel or oil has spilled as a result of the disable-ment, no smoking and no open flame precautionsshould be enforced. Care must be taken to pre-vent exhaust flash from other vehicles being di-rected at the vehicle with spilled fuel or oil. Thespilled fuel or oil must be cleaned up thoroughlybefore attempting to start the recovered vehicle'sengine.

40. Positioning Gun Tubes

During main battle tank recovery the main guntube should be so positioned that it will not bedamaged in event of a collision. If a gun tube isinvolved as a result of the disablement such asmight occur on a nosed or overturned tank, thegun should be checked by support maintenancepersonnel before firing.

55

41. Operator/Driver Safety

Operators and other personnel in both the recov-ery vehicle and disabled vehicle should keep theirhatches closed during a recovery operation anduse their periscopes to view hand signals directedto them.

42. Safe Location of Personnel

Before a pull has started, all personnel on theground must be directed to move to a safe loca-tion relative to any rigging before applyingpower. When a cable is drawn taut and then sud-denly released by a break, its back lash can cuta man in half. Consider a winch cable under forcestretching like a rubber band and storing upenergy. If such a line breaks, its snapping backcan be compared to the action of a whip with thevelocity of a rifle bullet. A winch rigging thatforms an angle is similar to a sling shot. If ablock were attached in the angle of the riggingand the attachment were to break, the blockwould be hurled through the angle at a terrificspeed and if the block left the cable it would bepropelled a great distance. It stands to reasonthat personnel should never stand within any an-gle formed by the rigging. A rule to follow forsafe location of personnel on the ground is: standat a distance from the rigging greater than thatdistance between the two farthest apart riggingpoints and never within an angle. Unsafe areasare illustrated in figure 43.

43. Signalman

For safe control of a recovery operation, there

56

should be only one signalman. The operatorsmust know the meaning of the signals to be usedand act only on those signals. The signalmanmust be in a safe location and where his signalscan be observed by the operators.

44. Impact Loads

Power should be appplied slowly to avoid possibleimpact loads on the rigging. An impact load iscaused when the slack is removed from a riggingsuddenly by dropping the load, moving the ve-hicle, or accelerating the winch. In either casethe same effect occurs-this sudden force ofweight times velocity, like the blow of a hammer,places an excessive force on the rigging and us-ually results in breakage.

CHAPTER 5

RECOVERY PROCEDURE

45. Recovery Procedure

During any recovery operation, a tried and prov-en procedure should be used to assure quick andsafe accomplishment. A haphazard approach to arecovery problem or the trial and error methodcan only result in a prolonged immobility of thedisabled vehicle, loss of valuable time, damage toequipment, and possible injury to personnel. Thefollowing eight-step recovery procedure, in theproper sequence, should be used in any recoveryinvolving winching.

46. Step 1-Reconnoiter Area

Check the terrain for an approach to the load,method of rigging, and natural anchors. As witha tactical mission, a recovery crew must knowthe problem before decisions are made. A com-plete ground reconnaissance should be made ofthe area and should include selection of the bestroute of approach to the disabled vehicle to pre-vent possible disablement to the recovery vehicle.Determine the method of rigging as explained in

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RECOVERY PROCEDURE

RECONNOITER AREA

ESTIMATE SITUATION

CALCULATE RATIO

OBTAIN RESISTANCE

VERIFY SOLUTION

ERECT RIGGING

RECHECK RIGGING

YOU ARE. READY

Figure 44. Recovery proc"dure.

Figure 45. Towing a cargo truck from mire.

paragraph 29, and check for available naturalanchors.

47. Step 2-Estimate the Situation

Determine the load resistance and the capacityof effort available. Estimate the resistance cre-ated by the load as explained in paragraph 6. For

59

most recovery operations involving winching, theeffort available would be the maximum capacityof the winch. In some recovery operations, par-ticularly with the wrecker truck, the maximumdistance between the winch and the disabled ve-hicle may be restricted and the effort availablemay be as little as half the winch capacity.

48. Step 3-Calculate Ratio

Compute an estimated mechanical advantage forthe rigging. Divide the resistance of the load asdetermined in step 2 by the effort available (thecapacity of the winch) as in paragraph 17.

49. Step 4-Obtain Resistance

Compute the tackle resistance and total resist-ance. Determine the resistance of the tackle asexplained in paragraphs 18 and 19. Ten percentof the load resistance determined in step 2, mul-tiplied the number of sheaves in the rigging. Addthe determined resistance of the tackle to theload resistance to obtain the total resistance.

50. Step 5-Verify Solution

Compute line forces to compare with the winchand dead line capacities. Divide the total resist-ance computed in step 4 by the mechanical ad-vantage estimated in step 3; the result is theforce of the fall line, as explained in paragraph20. The fall line force must be less than the capa-city of effort; therefore, this step of the recoveryprocedure is the key step to solving the problem.When verifying the solution, if the computed fallline force is greater than the effort, the mechani-

60

cal advantage must be increased. Note that nophysical work has taken place to this point;therefore, no time is lost moving equipment orhaving to re-erect rigging equipment. By beingable to compute dead line force as outlined inparagraph 21 and determine the strength ofequipment and sling leg capacities using infor-mation in paragraphs 24 and 25, the correctequipment to use as dead lines may be selected.

51. Step 6-Erect Rigging

Orient the crew and instruct them to assemblethe tackle and then move to a safe location. Therecovery chief should advise the crew membersof the plan and assign them to erect the tackle.Each crew member should be assigned a specifictask to perform, a crew member who finished histask should assist those who are having difficulty.The crew members can save much time by havinga thorough knowledge of the tackle to be erectedand by helping each other. All safety precautionsexplained in paragraphs 32 through 36 should beobserved.

52. Step 7-Recheck Rigging

Insure that tackle is erected for proper and safeoperation. The recovery chief will direct the op-erator to remove most of the slack from thelines; then he will inspect to insure correct as-sembly as explained in paragraphs 33 through38. If any corrections must be made, the recoverychief will direct the crew members to make them.He will explain the actions to be taken during

61

the operation to the recovery vehicle operator andthe drivers of the other vehicles involved and di-rect them to be prepared to act on signals as ob-served through their periscopes. Then the recov-ery chief will move to a safe location as explainedin paragraphs 42 and 43, where his signal can beobserved by the operators of both vehicles.

53. Step 8-You Are Ready

Signal the operator to apply winch power andrecover the load. The recovery chief must be alertduring the operation, ensuring that nothing ob-structs the operation of the equipment and thatall personnel on the ground remain at a safe lo-cation.

Note. This eight-step procedure as outlined in para-graphs 46 through 53, in the proper sequence, should befollowed during all recovery operations requiring winch-ing. To assist in memorizing these steps and their se-quence, they are so arranged that when in the propersequence, the first letter of each step will spell out theword recovery (fig 44). This plan is not restricted to re-covery crews for application and supervision, but is alsoof value to commanders for determining the efficiency oftheir recovery crews and the need for training.

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CHAPTER 6

VEHICLE RECOVERY OPERATIONS

Section i. SIMILAR VEHICLES

54. Vehicle Recovery Operations

The amount and type equipment employed as thesource of effort during any recovery operation isdependent upon the level of recovery as discussedin chapter 2. Every effort should be made by thedrivers and crews to accomplish the recovery be-fore calling on support from a higher level. Dur-ing combat it may be of the utmost importancethat cargo reach its destination at a definite timeor that personnel or cargo be picked up at a giventime or that a combat vehicle be at a given placeat a specific time. The use of similar vehicles forrecovery usually constitutes the quickest methodof recovery because similar vehicles are readilyavailable. Recovery support should be called upononly when the similar vehicles are not adaptableto the situation or when the tactical situationdoes not permit their use. Engaged combat ve-hicles should never be diverted for the purposeof recovery.

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Figure 46. Winching with a similar vehicle.

Figure 47. Self-winching operation.

55. Use of Similar-Type Wheeled Vehicles forRecovery

Similar wheeled vehicles can be used as thesource of effort to perform recovery by towingand winching.

a. To recover a mired truck by towing with a

similar vehicle, a tow chain should be used be-tween the towing and the mired vehicle, attached

64

to one of the lifting shackles of the mired vehicleand a front lifting shackle on the towing vehicle.If a greater working distance is required to en-able the towing vehicle to get better traction,then the tow chains from both vehicles should beused. Power must be applied slowly to preventplacing an impact on the chain and liftingshackles. A chain, unlike a cable, will not stretchand can easily be broken by impact. If one tow-ing vehicle cannot attain sufficient towing effortto overcome the resistance, another towing ve-hicle can be used in tandem with the first (fig45).

b. To recover a mired cargo truck, a truck ofequal or greater capacity should be used to per-form the winching operation. As an example, amired 21/2-ton cargo truck may be winched witheither a 21/½-ton or 5-ton vehicle. All winch-equipped trucks are authorized a single sheavesnatch block and one tow chain for rigging. Amechanical advantage is required if the resist-ance of the mired truck is greater than the winchcapacity. The winching vehicle must be posi-tioned in line with the mired vehicle so the cor-rect fleet angle is obtained as explained in para-graph 9b. The winch cable must be free spooledfrom the drum and the free end of the cable at-tached to one of the winching vehicles front lift-ing shackles or to a separate anchor. A chainsling is formed between the lifting shackles ofthe mired vehicle and the snatch block is at-tached in the apex of the sling. The loop formedin the winch cable is placed in the snatch block

65

Figure 48. Towing with similar vehicles.

A/

Figure 49. Towing mired tank, using one similar vehicle.

and power is applied to the winch to remove theslack from the cable (fig 46).

c. A winch equipped mired vehicle can performa self-recovery. The rigging is similar to thatused for similar vehicle recovery except thesnatch block is attached to a suitable anchor andthe free end of the cable attached to one of themired vehicle's front lifting shackles. A fixedblock will gain a mechanical advantage on a self-winching operation even though the sheave of theblock is performing as a first-class lever because

66

the source of effort (the winch) is part of theload; therefore, both the fall line and return lineare attached to the load and supporting it. Sincethere are two lines supporting, the load a 2 to 1mechanical advantage is obtained (fig 47).

56. Towing Disabled Wheeled Vehicles

A vehicle of the same size or larger can be usedto tow the disabled vehicle. A tow chain can beused for the hookup. The chain is attached to thelifting shackles as outlined in paragraph 55a. Adriver must be in the towed vehicle to control it(fig 48). Check the towed vehicle's technical man-ual for precautions to be observed and the prep-arations necessary to tow the vehicle. The towingspeed never should exceed that which is outlinedin the technical manual (TM).

57. Use of Similar-Type Tracked Vehicles forRecovery

The number of tracked vehicles required for aspecific recovery is dependent upon the resistanceto be overcome, the type of disablement, and theconditions of the terrain on which the towingvehicles must be operated. The rigging is accom-plished using the vehicle tow cables attached tothe tow hooks of the vehicles. All main battletanks carry two tow cables; light tracked vehiclescarry one tow cable.

a. Whenever two tow cables are used betweentwo vehicles, they should be crossed. This pre-vents the cables from entangling in the tracks onturns and maintains alinement of the vehicles

67

(fig 49). If a greater working distance betweenthe pulling vehicle and the mired vehicle is re-quired, tow cables can be joined together by us-ing tow hooks.If two towing vehicles are required for an opera-tion, only one tow cable is required between thetowing vehicles because the strength of one towcable is slightly greater than the pulling effort ofthe second pulling tank; however when two towcables are available they should be used to main-tain alinement and equalize the pulling effort(fig 50).

b. The recovery of a nosed tracked vehicle mayrequire as many as three similar vehicles, depend-ing on the degree to which it is nosed and theconditions of the terrain on which the pullingvehicles must operate. In extreme situations, asource of effort may be necessary to lift the frontof the nosed vehicle. To use a lifting vehicle, twoor more tow cables should be connected togetherto obtain a greater working distance between thenosed vehicle and the lifting vehicle. The liftingvehicle should be positioned facing the nosed ve-hicle. The cables of the pulling vehicles are con-nected in the same manner as for recovery of amired vehicle. Power should be applied to all theassisting vehicles at the same time, until thefront of the nosed vehicle is raised, and startsmoving rearward; then the lifting vehicle shouldmove forward slowly supporting the vehicle untilit is recovered. If there has been any spillage ofoil or fuel in the nosed vehicle, its engine shouldnot be operated until such spillage has beencleaned up (fig 51).

'a

P'igu'-e 50. Towing mi-

Figure 50. Towing mired tank, using two similar vehicles.

Figure 51. Recovering nosed tank with similar vehicles.

c. An overturned tracked vehicle can be up-righted by using three similar vehicles. One ve-hicle is used to pull the overturned vehicle up-right; the other two vehicles are used to hold andretard the fall of the overturned vehicle to pre-vent its crashing down on the suspension system.Tow cables should be connected together in pairsto allow safe working distance. The cable used toupright the overturned vehicle should be con-

69

0I

Figure 52. Recovering overturned tank with similar .ve-hides.

HOLDING VEHICLE(WHEN NEEDED)

Figure 53. Towing disabled tank with similar vehicles.

nected to the nearest center roadwheel arm sup-port housing on the upper side of the overturnedvehicle. Never connect to any other part of thesuspension system, turret, or the tie down eyes.The two vehicles used for holding should be posi-

70

tioned at a 30 to 450 angle from the overturnedtank with their cables connected to the tow hookson the high side of the overturned vehicle. Theholding vehicles are so positioned to prevent dam-age to the cables or the fenders and lights of theoverturned vehicle as it is uprighted. Drivers ofthe holding vehicles shift to low range; the pull-ing vehicle applies power gradually in reversewhile the holding vehicles move forward onlyenough to keep their cables taut until the over-turned vehicle passes through the point of bal-ance. As the overturned vehicle passes throughthe balance point, the holding vehicles move for-ward slowly, supporting the overturned vehicleand lowering it onto its suspension system (fig52). Because of spilled oil and fuel that will nor-mally be present, extreme caution must be exer-cised to prevent smoking or open flames near theoverturned vehicle.58. Towing Disabled Tracked Vehicles

A disabled tracked vehicle can be towed by asimilar vehicle of the same weight class usingtwo tow cables. The tow cables should be crossedto prevent entanglement with the tracks. Adriver will be required in the towed vehicle tooperate the brakes. The driver in the towed ve-hicle should be alternated frequently with thedriver in the towing vehicle, because of carbonmonoxide gas. The technical manual pertainingto the towed vehicle should be checked t deter°mine the preparations necessary and the precau-tions to be used to prevent further damage to thetowed vehicle. The towing speed should never ex-

ceed that which is outlined in the TM. If the dis-abled vehicle has defective brakes or its universaljoints are disconnected, another similar vehiclewill be required for holding (fig 53).

Section II. RECOVERY EXPEDIENTS

59. Recovery ExpedientsMilitary operations will require vehicles to oper-ate in remote areas where, should disablement oc-cur, assistance would not be readily available.Under these conditions, the driver or crew mustattempt self-recovery by the use of expedients.An expedient is an improvised method and is ac-complished with the materials on hand.

60. Substitutes for a Jack

a. When an outside dual tire becomes flat, anda jack is not available, the inside dual may berun up on a small log or rock. This takes theweight from the outside wheel and allows it tobe removed for repair or replacement (fig 54).

Note. This expedient is applicable to those vehicleswith dual wheels that are secured separately.

b. Another variation that may be used whenno jack is available, is to cut a piece of timberlonger than the distance from the axle to theground. Place one end of the timber against theaxle at an angle with the other end in a shallowhole, and drive the vehicle onto the timber. Setthe brakes and block the vehicle securely (fig 55).

c. To raise the front wheel of a cargo truck,secure a timber approximately 5 feet long to thefront bumper at an angle with a chain or rope,

72

Figure 54. Substitute for jack to remove outside dualwheels.

'kI ~1 mm ~I

Figure 55. Substitute for jack to remove tandem wheels.

place bottom end of timber in a shallow hole,then move the vehicle forward until the timberis in a vertical position and the wheel clears the

73

Figure 56. Substitute for jack to remove front wheel.

ground (fig 56). Set the brake and block the ve-hicle securely.

61. Use of a Pry

A pole can be used to pry a 1/4-ton truck out of aditch by lifting the front end of the truck withthe pole as illustrated in figure 57, and applyingpower to the truck in reverse gear.

62. Use of Wheels for Winching

On wheeled vehicles not equipped with a winch,the rear wheels may be used to assist in recover-ing the vehicle. On a dual-wheeled truck, a ropewith one end fastened to the wheel hub and theother end anchored, will cause the rope to be

74

Figure 57. Pole used as a pry.

wound between the dual wheels providing thesame action as a winch. The end of the rope thatis fastened to the wheels should be run betweenthe duals and through one of the holes in thewheel disk. Care should be taken not to place therope through a hole in the wheel disk where thevalve stem is located. A bowline knot is tied inthe end of the rope and slipped over the hub(fig 58). Tie a second rope in the same mannerto the dual wheels on the other end of the axle(fig 59), then place the vehicle in reverse gear;the ropes will wind between the two duals, caus-ing the vehicle to move rearward.

If the truck has single wheels, such as the M715and M151, the same expedient can be used byplacing a bar through the hole in the end of the

75

Figure 58. Attachment of rope to dual wheels to be usedas a winch.

axle flange. A rope is attached to the wheels oneach side of the vehicle by fastening them to thebars with figure 8 hitches (fig 60). Applyingpower will cause the ropes to be wound aroundthe hubs and move the vehicle.

63. Use of an A-Frame

Frequently a truck will become nosed in a shellhole or narrow ditch. When a truck becomes dis-abled in this manner, both lifting and pullingforces are required to make the recovery. Thelifting force can be obtained from an A-frame.To construct an A-frame, two poles approximate-ly 8 feet long and large enough in diameter to

76

F -)W~~.-

Figure 59. Using wheels as a winch.

support the front end of the truck will be needed.The poles should be lashed together at the topby a figure 8 or girth hitch (fig 61). The lowerend of the poles should be placed in the ground10 to 12 inches deep to prevent them from slid-ing when power is applied. The upper end of theA-frame is laid across the hood of the vehicleand the attachment made as in figure 62. If thenosed truck is equipped with a winch, the winchcable should be rigged for a 2 to 1 mechanicaladvantage, with the end of the cable secured tothe apex of the A-frame.64. Anchoring Tracks

Vehicles often become bellied (high centered) on

77

Figure 60. Attachment of rope to single wheels to be usedas a winch.

stumps, rocks, dry ridges, or mire. In this posi-tion, vehicles are immobilized because of the lackof traction.

a. To recover a bellied vehicle obtain a log longenough to span the width of the vehicle and ofsufficient diameter to support the vehicle weight.The log is placed against both tracks and a towcable is placed so one end of the cable goes overthe log and through the tracks from the inside.The other end of the tow cable is placed under-neath the log, and the ends of the cable are con-nected together with a tow hook on the outsideof the track to facilitate disconnecting. The sameprocedure is followed to attach the log to the

track on the opposite side of the vehicle (fig 63).By gradually applying power to the tracks, the

78

GIRTH HITCHON

A-FRAME >

FIRST STEP

LOO P / LOOPy

SECOND STEP THIRD STEP

FALLUNDER

XI $.i1PT TOP POLE

LOOPTO TKE UP

FOURTH STEP SLACKFIFTH STEP

Figure 61. Tying girth hitch to A-frame

slack in the tow cables will be taken up, pullingthe log underneath the tracks until it comes incontact with the obstacle, anchoring the tracksand causing the vehicle to move.

Caution. Care must be taken to stop the vehiclebefore the log reaches the fenders, to preventdamage to the fenders and tow cables.

b. For a bellied disablement other than mire,the tracks can be anchored using two tow cables.

79

Figure 62. Recovery of a nosed truck using an A-frame.

Figure 63. Log used to anchor tracks.

Connect the tow cables together with a tow hookand attach the cables to both tracks by passingthe ends of the cables through the tracks from

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l' a

Figure 64. Cables used to anchor tracks.

2 EACH

Figure 65. APCAT expedient kit.

the outside and attaching them to the standingparts of the cables with tow hooks (fig 64). Whenpower is applied to the tracks the cable will con-tact the obstacle and anchor the tracks. The samecaution must be exercised as outlined in a above.

c. APCAT (Armored Personnel Carrier An-choring Tracks) device. Armored personnel car-riers may fail to exit the water after swimming

81

Figure 66. APCA T expedient.

due to steep banks or adverse terrain conditions.As an aid to water exit, the APCAT expedientcan be used. The APCAT expedient kit consistsof one pair of track anchor blocks fabricated lo-cally and 200 feet of 1-inch fiber rope (fig 65).The track anchor blocks are placed in the vehicle

82

P-- .cAPSTAN ': ?

/1rl3 em? ANC.OR

Figure 67. Capstan kit.

track sprocket holes in each track and the ropeis then attached from the blocks to suitable an-chorages. As power is gradually applied, thetracks will anchor themselves to the blocks andcause the vehicle to move (fig 66). This expedientmay also be used in mire or bellied situations.

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Figure 68. Capstan recovery of an armored personnelcarrier.

Figure 69. Moving a vehicle with both tracks broken.

65. Capstan Winching of Armored Personnel Carrier

When leaving water after swimming operations,an armored personnel carrier may become dis-abled because of the steep angle of the bank, themuddy or slippery surface of the bank or a com-bination of both, and cannot exit. A capstan ex-pedient can be used for a self-recovery. The cap-

84

H·. .!~

Figure 70. Moving a vehicle onto a track.

Figure 71. Rigging a rope to a drive sprocket hub.

stan kit consists of one pair of capstan adaptersthat bolt to the drive sprocket hub, one pair ofcapstan drums with mounting tee bolts, nylonrope, and one pair of ground anchors (fig 67).Normally the capstan adapters are permanentlymounted to the drive sprocket hubs with the me-tal shroud plates cut away. The capstan drumscan be very quickly installed to the adapters withthe drum tee bolts. The rope is secured to eachmounted capstan drum, and wrapped two orthree turns around the drums on both sides ofthe vehicle. Care must be taken to ensure thatthe anchors are positioned in line with the cap-stan drums. The ropes must extend from the un-derside of the capstan drums to the anchors, andall slack must be removed from the ropes beforethey are tied to their respective anchors. By ap-plying power to the tracks, the ground anchorswill imbed in the ground, and the winching ac-tion of the capstan drums will cause the vehicleto move (fig 68).

66. Moving Tracked Vehicle With Both Tracks BrokenWhen both tracks of a tracked vehicle arethrown, it may become necessary to break bothtracks in order to move the vehicle so the trackscan be remounted. Break one track and attach acable from the drive sprocket hub to an anchor.This will support the vehicle so the other trackcan be broken. Chocking must be used to preventthe vehicle from rolling out of control. As the en-gine power is applied to the drive sprocket at-tached to the cable, and steering action is applied,

86

Figure 72. Installing a track.

the vehicle will move by the winching action ofthe drive sprocket hub (fig 69).

67. Moving a Vehicle onto a Track

To move a vehicle onto a track, the vehicle isfirst alined with the track, and then a plank typeramp is positioned on the end of the track. In asituation where a ramp is not available, a shal-low ditch is dug for the end of the track to layin for the same results (fig 70).

68. Onstalling a BIroken Trach¢

To install a broken track, aline the track withthe road wheels so center guides will pass be-tween the road wheels when the vehicle is moved.The vehicle is stopped so that the road wheel is

87

resting forward enough to allow the track to bepassed over the sprocket. A rope is then tied tothe center of the track pin on the rear track link,the rope is then passed over the center guidegroove of the sprocket hub, around and betweenthe rear support roller wheels, and back aroundthe sprocket hub making two turns as illustratedin figure 71.As power is applied to the sprocket and the freeend of the rope is held taut, the end of the trackis pulled up to the sprocket (fig 72). Once thesprocket has engaged a minimum of three tracklinks, the sprocket is stopped, and the rope is re-moved from the sprocket hub and extended for-ward over the compensating idler wheel to guidethe track as the vehicle is moved forward. Whenend of the track has passed over the compensat-ing idler, the track can be connected.

69. Helicopter Recovery of Mired Vehicles

Cross-country operation of tracked vehicles- ininundated areas, such as rice paddies andswamps, may result in a vehicle becoming miredin such a position that other vehicles cannot getclose enough to perform the recovery without be-coming mired. In this type of situation, use of ahelicopter may be the best method because thehelicopter's mobility is not affected by the ter-rain; it can hover above a disabled vehicle, allow-ing a rigging to be attached to the disabled ve-hicle. The recovery of the M113 APC and somewheeled vehicles has been accomplished using ahelicopter with a lifting capability of approxi-mately 71/2 tons.

-R

4 NYLON STRAPS16 FEET LONG RIGGING TO MIRED VEHICLE

"FOUR-LEGGED HORSE" KIT

CHAIN ON EACH STRAPFOR ATTACHMENTCHAIN IS RUN THROUGH EYEAND BACK THROUGH SELF-LOCKINGDEVICE

Figure 73. "Four-legged horse" kit.

a. The attachment used between the helicopterand the mired vehicle is a standard lifting sling

89

Figure 74. Two sling legs attached to each front towinglug.

used to transport equipment. This sling is termedas a "four-legged horse" kit, with a strength of15,000 pounds. The legs of the sling are made ofnylon straps with a chain and a self locking de-vice on their free end (fig 73). The sling in ap-plication can be attached to either the four lift-ing eyes, or to the towing lugs (eyes). The place

90

Fge7 -R

Figure 75. Recovery with sling attached to towing lugs.

where the sling is attached on the mired vehicledepends on the mire situation.

b. In a mire situation in which the towing lugsare exposed. The helicopter drops the sling ontothe mired APC, and the crew members then at-tach two sling legs to each of the front towinglugs, as in figure 74. The helicopter hovers overthe mired vehicle, so the doughnut of the slingcan be attached to the helicopter lifting hook.The helicopter then lifts and pulls on the vehicleconcurrently with power being applied to thetracks of the mired vehicle for..the recovery (fig75).

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Figure 76. Recovery with sling attached to all four liftingeyes.

c. In a situation in which the towing lugs werenot exposed, the sling can be attached to the fourlifting eyes (fig 76) or to only two lifting eyes(fig 77).

Section III. EXPEDIENT REPAIRS

70. Expedient Repairs

Should mechanical malfunctions disable a ve-hicle, expedient repairs can be performed by the

92

Figure 77. Recovery with sling attached to only twolifting eyes.

Figure 78. Skid expedient.

crew. Expedient repairs are such that crewmenwith limited mechanical training can apply them

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Figure 79. Raising tandem axle.

PROPELLER SHAFTFRONT REAR AXLE

BRAKE HOSE AND SHORT CHAINBRAKE HOSE SUPPORTSPRING

Figure 80. Attaching tandem axle to frame.

with a sufficient amount of accuracy to restoreoperation to the disabled vehicle. However, expe-dient repairs are to be used as an emergencymeasure only and will never be used in lieu ofnormal maintenance repair procedures.

94

71. Damaged Wheel

When a driver finds himself in an isolated areawith a flat tire or damaged wheel and he doesnot have the equipment to repair it, a skid maybe used on 4-wheel-drive type vehicles. The skidshould be used on the rear wheel (fig 78).(Wheels can be changed from one hub to anotherto accomplish this.) A pole approximately 4inches in diameter and 6 to 8 feet long shouldbe used. After the vehicle is raised, one end ofthe pole is placed above the frame crossmembernear the transmission and the other end on theground. The pole should pass under the springU-bolts, aline with the spring, and be lashed se-curely to the spring. The pole will then supportthe weight of the vehicle on the side with thedefective wheel. By engaging the front wheeldrive, the vehicle will move under its own power.

72. Disabled Tandem Axle

When a tandem axle has a burned-out bearing ordamaged wheel that would disable the vehicle orcause further damage if continued in operation,the axle may be tied up and made inoperative.The wheel of the disabled axle should be movedonto a rock, log, or similar object to raise thewheel as high as possible (fig 79).While the wheel is raised, the axle should be tiedas tightly as possible to the frame by using heavywire or a tow chain (fig 80). Caution should beexercised to prevent the chain or wire from caus-ing damage to the brake lines. If the wheel bear-ing is burned out, or for some similar reason the

95

r :~ ~~~~ ~ ' ~PR'OPELLER SHAFTFRMit TO FRONT REAR AXLE

BRAKE HOSE ANDBRAKE HOSE SUPPORT 16-FTSPRING TOW

CHAIN

Figure 81. Disabled tandem axle.

REMOVE AXLES

DEFECTIVE DIFFERENTIAL

REMOVE PROPELLER SHAFT

Figure 82. Defective differential.

wheel should not turn, the axle shaft should beremoved from the axle housing and the hole inthe hub stuffed with rags to keep out foreignmatter. This expedient will allow the other wheelsto drive.This same expedient may be applied to both endsof the axle if both wheels are defective (fig 81).

96

DISTRIBUTOR

S PRI NG

CAM//

RUBBER CONTACT POINTSBENT DOUBLE

Figure 88. Substitute for distributor point spring.

With both ends of axle tied up, the truck shouldnot be loaded too heavily.

73. Defective Differential

If the defect is in the differential of a 4 x 4 or6 x 6 vehicle, the propeller shaft and drive axlesmay be removed from the defective assembly andthe vehicle operated on power supplied by theother axles. For example, if the front rear dif-ferential is defective and the rear propeller shaftis removed, the vehicle may still be powered bythe front wheels. When the axle shafts are re-moved, the openings in the ends must be coveredsecurely to keep out dirt and foreign matter (fig82).

74. Broken Distributor Point SpringA brcken distributor point spring will result in

97

NAIL ORWOOD WEDGE

BATTERYTERMINAL POST

CABLE CLAMP

Figure 84. Battery cable clamp repair.

COUPLING NUTSTRING RAPPED TIGHTIN DIRECTION SHOWN

FLARED PIPE

Figure 85. Leaking low-pressure line fitting.

the engine cutting out and finally stopping. Tosubstitute for a broken spring cut a piece of rub-ber from a tire, or vacuum hose, and double itand place it between the movable point and thedistributor housing (fig 83). The rubber will actas a distributor point spring. The engine willthen start and perform at low speeds, but the

98

Figure 86. Repair of cracked low-pressure oil or fuel line.

~.~ J CRIMP ENDS

OF TUBESFigure 87. Repair of puncture radiator core.

rubber cannot close the points fast enough toperform properly at high speed. The rubber maywork itself out of position and have to be re-placed occasionally.

75. Loose Battery Clamp

When a battery cable clamp becomes loose andcannot be tightened anymore, a nail or metallicwedge may be used to make contact between thebattery post and the cable clamp. The clamp must

be loosened, the wedge inserted between the bat-tery post and clamp, and the clamp tightened(fig 84). When working with tools around bat-teries and battery clamps, care must be taken toprevent arcing, causing possible damage to ve-hicle electrical components or personal injury.

76. Leaking Low-Pressure Line Fitting

To repair a leaking low-pressure line fitting, astring or rag may be wound tightly around theline behind the flare (fig 85). Slide the couplingnut over the material, screw it onto its connec-tion, and tighten it securely against the packingstring with a wrench. The string will act as agasket and seal the leak. The string should bewound clockwise--in the same direction the cou-pling nut is turned to be tightened.

77. Cracked Low-Pressure Oil or Fuel Lines

Cracked low-pressure oil or fuel lines usually arecaused from extreme pressure, vibration, or de-fective metal. The leak may be stopped by wrap-ping the line tightly with friction tape held inplace by wire. The wire will help the tape with-stand pressure, and usually the leak will bestopped until a permanent repair can be made(fig 86).

78. Punctured Tube-Type Radiator Core

Radiators are punctured frequently when vehiclesare operating in wooded or combat areas. Whenthis happens, the cooling fins should be cut andpushed away from leaking tubes, cut the leaking

100

ROPE

EXPEDIENT GENERATOR PULLEY

CRANKSHAFT PULLEY

Figure 88. Fan belt substitute.

TANK WALL

SCREW OR BOLT WASHER

PIECE OF HOSE

PIECE OF HOSEEXPANDS RADIALLYAND SEALS HOLE

Figure 89. Repair of punctured fuel tank.

101

tube in half, and fold the ends of the tube backabout three-fourths of an inch. Close the tubeends by pressing them flat with pliers (fig 87).The efficiency of the cooling system is reducedwhen several tubes are cut, and the engine mayoverheat. When field expedient repairs of the ra-diator have been made, the radiator cap shouldbe loosened to keep radiator pressure from build-ing up, thereby reducing the possibility of break-ing the repair.

79. Damaged Front Axle Brake System

When damage has occurred to the front axlebrake system, a method of repair is to close theline at the junction block to the axle. This willassist the driver in maintaining steering controlwhile braking and will allow pressure buildup inthe rear brakes.

80. Broken Fan Belt

When a fan belt breaks and a replacement is notreadily available, a fiber rope from the vehicletarpaulin or a piece of field telephone wire maybe used as a substitute. The rope or wire shouldbe looped around the pulleys three or four times,pulled as taut as possible, and tied with a squareknot (fig 88).

81. Broken Fan Blades

A broken fan blade will cause excessive vibrationof the engine, making it dangerous to operate theengine. Remove the remainder of the blades. Thevehicle may be operated, however, caution shouldbe exercised to prevent over heating.

102

SHEAR PIN

Jo WORMSHAFT

COTTERKEY END |TAPE

WOOD DOWEL

Figure 90. Substitute shear pin.

82. Punctured Fuel Tank

To repair a punctured fuel tank, use a piece ofhose about the size of the punctured hole in thefuel tank, a bolt, nut, and two flat washers. As-semble the washers and piece of hose on the boltand screw the nut down snugly. Enlarge the holein the fuel tank, if necessary, so the assembledbolt and hose will pass into it and fit snugly;then hold the hose to prevent its turning, andtighten down on the bolt. This will cause thepiece of hose to expand in the hole and seal theleak (fig 89).

83. Shear Pin Substitute

A substitute for a broken shear pin may be madeby punching out the remains of the broken shearpin, cutting the remains in half, and insertingthe two shear pin halves with a short, woodendowel between them as illustrated in figure 90.

103

CAP SCREW

END END \PLUG PLUG GASKET

Figure 91. Expedient method for removing torsion bar.

Wrap friction tape around the shaft to cover theshear pin hole and prevent the end of the substi-tute shear pin from dropping out. A steel bolt,spike, nail, or screwdriver blade should not beused as a substitute shear pin, because it mayresult in damage to the winch and cable.

104

Figure 92. Road wheel expedient applied.

Figure 95. Damaged track and suspension.

Figure 94. Short track expedient applied.

105

Figure 95. Direct-pull winching operation.

Figure 96. Winching with a 2 to I mechanical advantage.

84. Damaged Road Wheel Components

To operate a vehicle with a damaged road wheel,spindle, or road wheel arm, the arm must be tiedup out of the way. To tie the road wheel arm up,

106

the torsion bar must be removed. This can bedone by positioning the vehicle across a ditchnarrow enough to permit the front and rear roadwheels to support the weight of the vehicle, anddeep enough to permit the track to sag awayfrom the defective road wheel. If a ditch is notavailable, a trench can be dug. The vehicle inthis position will allow the road wheel assemblyto sag and remove the tension from the torsionbar. The torsion bar is then removed by removalof its capscrew and end plug, replacing capscrewin the torsion bar, and prying behind the cap-screw head with a track fixture handle as illus-trated in figure 91.The vehicle is then repositioned on level groundwhere the road wheel is removed, a crowbar posi-tioned across two torsions bar support housings,and the road wheel arm tied in a raised positionto the crowbar with rope from the vehicle tar-paulin (fig 92). This expedient is only applicableto intermediate road wheels.

85. Damaged Suspension Components

A armored personnel carrier with a damagedtrack, rear road wheel arm, and idler wheel (fig93), can be operated by using the short track ex-pedient. To apply this expedient, companion com-ponents to the damaged suspension parts such asthe rear shock absorber, track adjuster, roadwheel arm and torsion bar must be removed. Togive the vehicle better stability, number 3 roadwheel with arm is moved to the rear road wheelposition. Due to the absence of' the idler wheel,

107

sufficient track blocks must be removed to permitthe track to be connected (fig 94).

Section IV. SPECIAL PURPOSE VEHICLES

86. Special Purpose Vehicles

This section describes and explains recovery op-erations performed with wrecker trucks and re-covery vehicles. Recovery operations using thesespecial purpose vehicles is performed by the re-pairmen of the companies or battalion. Specialpurpose vehicles are used for recovery when themethods used by the platoon are unsuitable to thesituation, or when their efforts have been unsuc-cessful. Wrecker trucks are designed for the re-covery of wheeled vehicles and recovery vehiclesare designed for the recovery of tracked vehicles.The methods of recovery performed, using spe-cial purpose vehicles, are winching, lifting, andtowing, as explained in chapter 2.

Note. This manual discussses the application of thevehicle's capability to winch, lift, and tow. Refer to thepertinent technical manuals for information relative tothe operation of the equipment and the specific capabilities.

87. Mired Truck

Factors that must be considered during the re-covery of a mired truck using a wrecker truckare: the resistance of the load, the approach tothe load, and the distance between the wreckerand the mired vehicle. An example of a very sim-ple winching operation is illustrated in figure 95.A direct pull is used because the resistance cre-

108

f 'V

Figure 97. Change of direction winching operation.

Figure 98. Lifting operation with wrecker truck.

ated by the mired vehicle is less than the winchcapacity of the wrecker.An example of a more complicated winching op-eration is illustrated in figure 96. A mechanicaladvantage and a change of direction pull is usedbecause the mired truck offers a resistance great-er than the winch capacity of the wrecker, and

109

the wrecker is unable to position itself in aline-ment due to the terrain.

88. Nosed Truck

The recovery of a nosed truck using a wreckertruck may require only a towing operation. Somesituations may require all three of the wreckertruck's capabilities (winching, lifting, and tow-ing) to complete the recovery. An example wouldbe the recovery of a 21/2-ton cargo truck that isnosed off a narrow road and is mechanically dis-abled. To perform the recovery, the wrecker truckis positioned on the road so that when the nosedtruck is pulled back up on the road, its front endwill be in line with the rear of the wrecker truck.A change of direction pull using the wrecker rearwinch is used to pull the truck onto the road asillustrated in figure 97.Then the front of the truck is lifted and thecrane traversed to place the truck directly be-hind the wrecker truck in preparation for towing(fig 98).

89. Overturned TruckTo upright an overturned truck using the wreck-er truck, a sling method of attachment must beused on the overturned truck, because a pullingforce applied to only one point of the frame willusually result in a bent frame. The sling attach-ment is made of two utility chains or 1 inch fiberrope. The sling ends are attached to the frontand rear lifting shackle on the high side of theoverturned truck, and then the winch cable is at-tached to the center of the sling. A holding effort

110

will be required to prevent the vehicle fromcrashing onto its wheels. The holding force couldbe another vehicle or a rope block and tackle withman-power, the attachment for the holding forcewould be through another sling attached to thesame points on the overturned truck as the pull-ing sling. If a holding vehicle is not available,rig a 4 to 1 mechanical advantage tackle fromthe equipment on the wrecker truck, attach it be-tween the holding sling and an anchor, and wrapits fall line around a tree as illustrated in figure99. Apply power gradually to the wrecker truckwinch until the overturned truck is past the ver-tical position, and then lower the truck to itswheels with the holding tackle. Caution must beexercised to prevent smoking or open flames nearthe overturned truck, because of the danger ofigniting spilled fuel and oil. If neither holdingvehicle nor holding tackle can be used, the wreck-er boom may be used to hold the load. Wheneverthe wrecker boom is used in this manner, maxi-mum use of the boom jacks should be made. Whenlowering the overturned truck to its wheels, al-ways lower it using the hoist winch, rather thanbooming out with the crane.

Caution. Do not overload crane capacity.

90. Towing Wheeled Vehicles

Frequently, it will be necessary to tow the re-covered vehicle to a repair shop with the wreckertruck. The method of towing depends primarilyupon the terrain over which the vehicle must betowed, and the mechanical condition of the dis-

111

Figure 99. Recovery of overturned truck.

abled vehicle. A wrecker truck is capable of tow-ing vehicles by the following methods:

a. Highway Tow. The tow bar is attached to

112

Figure 100. Highway tow using wrecker truck.

Figure 101. Cross-country tow with wrecker truck.

Figure 102. Recovery of a mired tracked vehicle with a2 to 1 mechanical advantage.

Figure 103. Recovering a mired tank with recoveryvehicle using a $ to 1 mechanical advantage.

the disabled vehicle's lifting shackle eyes and thewrecker truck tow pintle. All wheels of the towedvehicle are on the ground. A driver in the towedvehicle is not required (fig 100).

113

b. Cross-country Tow. A cross-country tow pro-vides better control of the towed vehicle whentowing over rough terrain. To rig for the cross-country tow, attach a chain lifting sling or thehoisting bar between the truck's front liftingshackles. Attach a tow chain from the wreckertow pintle to the disabled truck lifting shackles.Place the hoist block hook in the lifting slingand hoist the truck until the front wheels areapproximately 12 inches off the ground. Extendthe boom to remove the slack from the towingchain; this is done to prevent the towed vehiclefrom jamming into the rear of the wrecker truck.The boom should be supported with the shipperbraces to prevent impact loads on the cranemechanisms (fig 101). If the front end of thevehicle is damaged, the cross-country method oftow may be required even though the disabledvehicle is being towed on the highway. The towbar may be used in place of a tow chain.

c. Towing Precautions for Wheeled Vehicles.Extreme care must be exercised when towingdisabled vehicles to prevent further damage tothe vehicle. The vehicle technical manual shouldbe checked for preparation of the vehicle fortowing and the precautions that must be exer-cised. The following general precautions shouldbe exercised in any towing operation.

(1) Long and short hauls. Refer to per-tinent vehicle manual for preparation of vehicle.

(2) Towing speed. Never exceed 15 milesper hour while towing any type of wheeled ve-hicle.

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91. Mired Tracked Vehicles

a. Recovery With One Recovery Vehicle. Inmost mired tracked vehicle situations, the recov-ery can be accomplished using only one recoveryvehicle. In preparation for winching, the recov-ery vehicle must be positioned as nearly in lineas possible with the mired vehicle and at a dis-tance to obtain maximum winching capacity asdescribed in paragraph 29b and c to erect therigging. When a 2 to 1 mechanical advantage isrequired (fig 102), the block is attached to themired vehicle by the procedure described in para-graph 30b. If the resistance is such that a 3 to 1mechanical advantage is required, then onesnatch block is attached to a towing lug on themired vehicle; another block attached to the deadman lug on the recovery vehicle, and the free endof the winch cable attached to the other towinglug on the mired vehicle (fig 103).

b. Recovery With Two Recovery Vehicles.When the load resistance of a mired tracked ve-hicle is so great that the calculated fall line forceis greater than the winch capacity of one recov-ery vehicle with a 3 to 1 mechanical advantage,a second recovery vehicle is necessary for the op-eration. Rig each recovery vehicle main winchwith a 2 to 1 mechanical advantage. Attach thesnatch block of each rigging to a towing lug ofthe mired vehicle. The recovery vehicles shouldbe positioned side by side to allow the samelengths of winch cable to be used because of theirvariable capacity winches (fig 104). To synchro-nize winch speeds, both recovery vehicle opera-

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Figure 104. Recovering a mired tank with two recoveryvehicles.

Figure 105. Winching a nosed tank with a recoveryvehicles.\

Figure 106. Lifting operation to recover a nosed tank.

tors should set their engine speed at the desiredrpm with the hand throttle, and compensate withthe winch control lever to maintain taut cables.

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92. Nosed Tracked Vehicle

The method used in recovery of a tracked vehiclenosed in a deep trench or ravine with a recoveryvehicle depends upon the factors involved in thenosed situation. If the condition of the terrainbehind the nosed vehicle is level the recovery maybe accomplished by towing. If the nosed vehiclecannot assist in its own recovery and the condi-tion of the terrain is not suitable for towing, awinching operation can be performed as illus-trated in figure 105.If terrain features are such that the recoveryvehicle cannot be safely positioned behind thenosed vehicle, then the recovery can be accom-plished with the recovery vehicle positioned onthe opposite side of the ditch. Using the recoveryvehicle's boom with its maximum mechanical ad-vantage rigging, attach its hoist block to thefront lifting eyes on the nosed tank with a V-chain as illustrated in figure 106, the vehicle canbe lifted to the horizontal. If no oil or fuel spill-age existed on the nosed vehicle, it may assistin its recovery by applying power in reverse atthe same time the recovery vehicle is lifting. Ifthe nosed vehicle is not able to assist, then thefront of the tank would be lifted and pulled tothe opposite side of the ditch, where a towing orwinching operation could be used to complete therecovery. By constructing a rigging similar tothe type illustrated in figure 107, a combinationwinching and hoisting operation may be used torecover the nosed vehicle. By coo,:dinating thehoist winch and the tow winch, th .:- eight and

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Figure 107. Recovering an overturned tank with arecovery vehicle.

movement of the disabled vehicle can be con-trolled during the entire recovery operation.

93. Overturned Tracked Vehicle

To upright an overturned tracked vehicle with arecovery vehicle, position the recovery vehiclefacing the bottom of the overturned vehicle at adistance away that is equal to the width of theoverturned vehicle, plus 2 feet. For the upright-ing source of power, attach the main winch cableto the near center road-wheel arm support hous-ing on the high side, using a utility chain. Forthe holding source of power, rig the boom withits maximum mechanical advantage rigging, andattach its hoist block to two tow cables to forma sling. The opposite ends of the sling are passedunder the track and attached to the front and

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Figure 108. Highway tow with recovery vehicle.

Figure 109. Cross-country tow with recovery vehicle.

rear tow hooks on the high side of the overturnedvehicle as illustrated in figure 107. To uprightthe overturned vehicle, power is applied to themain winch until the vehicle is pulled past itspoint of balance and is being supported by thehoist rigging. Then by lowering the hoise winchrigging slowly, lower the overturned vehicle ontoits suspension system. Because of spilled oil andfuel that will normally be present, smoking oropen flames will not be permitted near the over-turned vehicle.

94. Towing Tracked Vehicles

Frequently, it will be necessary for the recoveryvehicle to tow a disabled vehicle to some pointwhere a repair is to be made. The method of towused depends primarily upon the type of terrainover which the vehicle is to be towed.

a. Highway Tow. The recovery vehicle's towbar is used. It is attached to the towing lug ofthe disabled vehicle as explained in paragraph30b(3), with the lunette of the tow bar installed

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Figure 110. Combat tow with a recovery vehicle.

in the recovery vehicle's tow pintle (fig 108). Adriver would not be required in the towed vehicle.

b. Cross-country Tow. To perform a cross-country tow with a recovery vehicle, crossed towcables are used between the recovery vehicle andthe disabled vehicle (fig 109) as when towingsimilar vehicles. A driver is required to apply thebrakes on the towed vehicle to prevent it fromoverrunning the recovery vehicle on down grades.

c. Combat Tow. The combat tow is used whenit is necessary to make a towing connection underfire to provide the least possible exposure of per-sonnel. The lifting V-chain is attached to the re-covery vehicle's tow pintle before it is moved tothe disabled vehicle's location. The recovery ve-hicle is moved into the area, backed up until con-tact is made with the back of the disabled vehicle.One of the disabled vehicle's crew members canslip through the escape hatch and connect the

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V-chain legs to the front tow hooks of the dis-abled vehicle. After the hookup is made he re-enters through the escape hatch, and the recoveryvehicle moves out, towing the disabled vehicle(fig 110).

d. Towing Precautions for Tracked Vehicles.When a disabled tracked vehicle is being towed,care must be exercised to prevent further dam-age to the towed vehicle. The vehicle technicalmanual should be checked for towing precautionspeculiar to the vehicle.

(1) For short hauls (less than 1/t-mile), thegearshift control lever must be in neutral (N)position.

(2), For long hauls (over /4-mile), to pre-vent possible damage to the transmission, thepower train should be disconnected at, the uni-versal joints to the final drives.

(3) Never exceed speed outlined in the tech-nical manual of the towed vehicle.

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CHAPTER 7

UNDERWATER VEHICLE RECOVERY

95. Underwater Vehicle Recovery

Due to the development of an underwater fordingcapability for the main battle tank and the factthat numerous other vehicles in the inventoryhave a swimming capability, it is highly probablethat some of these vehicles are going to becomedisabled while performing fording or swimmingoperations. As in land disablements, vehicles dis-abled in or under water must be restored to nor-mal operation quickly and safely. The samemethods of recovery apply and at all levels with-in the organization. Special training of personnelto enable them to work under water is required.The expedient method of recovery is not appli-cable to underwater recovery; however, some ex-pedient repairs may be accomplished, after thevehicle has been recovered from the water.

96. Load Resistance in Water

The resistances encountered during underwaterrecovery operations are determined in the samemanner as for land recovery. When flooded ve-

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hides are being pulled from water to land, theweight of the water must be considered when de-termining the resistance. In some instances, theresistance to be overcome will be less than therolling resistance of the same vehicle on land.

a. Floating-Type Vehicles.(1) The resistance of a mechanically dis-

abled floating-type vehicle to being moved on thewater is negligible, as compared to its rolling re-sistance on land and can be caused to move witha small amount of effort.

(2) If a floating-type vehicle is flooded andsubmerged, the resistance to movement on theriver bottom is determined in the same manneras on land by considering the weight of the ve-hicle and the river bottom conditions-sand,gravel, or mud. As an example: if the situationinvolves an M113 APC (weight 11 tons) floodedand located on the river bottom in mud at road-wheel depth, the resistance is estimated at 11tons.

(3) The greatest resistance encounteredwith flooded floating-type vehicles is the resist-ance created as the vehicle is being pulled fromthe water to land. Due to a great volume of watercontained in a submerged floating-type vehiclesuch as an M113 APC, the weight of the watermust be considered when estimating the resist-ance created by vehicle as it is pulled from thewater. The weight of the water is estimated asbeing equal to the vehicle's weight. Therefore, anM113 APC's weight as it is pulled from the waterwould be 22 tons, and the resistance created

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would depend on this weight and the terrain con-dition of the exit area.

b. Non-Floating-Type Vehicle.(1) The kinds of terrain disablements en-

countered during fording operations are the sameas on land operations-mire, nosed, and over-turned. The resistances are estimated in the samemanner by considering vehicle weight and typeof disablement. The resistance afforded by aflooded fording-type vehicle underwater is thesame as a similar type mechanically disabled onland.

(2) The weight of a flooded fording-type ve-hicle is greater than the vehicle's actual weight,for the same reason as that given for floodedfloating-type vehicles. However, the volume ofwater contained in a fording-type vehicle is muchless than that contained in a floating type. Theweight of water contained in a flooded fording-type vehicle is estimated as /8 the vehicle weight.As an example: a flooded 50-ton tank's weight asit is pulled out of the water is estimated to be50 tons plus 1/8 its actual weight or 56.25 tons.The amount of resistance created as the vehicleis pulled from the water depends on vehicleweight (56.25 tons) and the condition of the ter-rain in the exit area-sand, gravel, or mud.

97. Sources of Efforta. Similar Vehicles. Similar vehicles may be

used as the source of effort much the same as forrecovery on land and with the same restrictionsgoverning their use. The towing capability of a

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fording-type vehicle is considered to be the sameas on land and can be adapted to the same typeof disablements as on land. The gun tube of thetowing vehicle will require repositioning to pre-vent possible collision with the disabled vehicle.A floating-type similar vehicle can be used to towa floating-type vehicle on the water, even thoughthe floating-type vehicle does not have a towingcapability in water comparable to its towing ca-pability on land. The resistance of a floating ve-hicle is negligible.

b. Special Purpose Vehicles. Wrecker trucksand recovery vehicles are readily adaptable to un-derwater recovery operations. The winch cablesof the recovery vehicles are long enough to allowwinching operations from land to water in mostsituations.

98. Locating Submerged VehiclesThe first problem in any underwater recovery op-eration is the location of the disabled vehicle.This will not be difficult if the vehicle conningtower or guide rod is visible above the surface.If the vehicle has rolled over on its side ordropped into an underwater depression, it will benecessary to conduct search operations. It may benecessary in some situations to use dragging de-vices to locate the disabled vehicle. After the ve-hicle is located, it is necessary for divers to godown and find the front and rear of the vehicleto establish the approach route of the recovery ve-hicle. Lines and floats should be used to mark theposition of the vehicle. Empty water or gasolinecans can be used as floats..

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99. Methods of Attachment

The same attachments are made to vehicles dis-abled under water as are made to those disabledon land whether the recovery effort is similarvehicles or a winch. The only deviation from thenormal method of attachment is when the objectof recovery is a floating vehicle. The resistance ofa floating vehicle is considerably less than itsweight, therefore, it is more expeditious to at-tach the rigging to the lifting eyes. This allowsthe personnel who are making the attachment todo so without having to work in the water exceptto disconnect the tow hooks on the disabled ve-hicle. One tow hook would be attached to eachof the two lifting eyes front or rear and the towcables attached to the tow hooks (fig 111). Ifa similar vehicle is used for the operation, its towhooks would be attached to the lifting eyes before

Figure 111. Towing a floating vehicle with a swimmingvehicle.

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Figure 112. Towing a floating-type vehicle from waterto land.

entering the water. The tow cables would be at-tached and crossed as in the normal tow until thedisabled vehicle is towed to the shore (fig 112).The tow hooks should be reattached to the tow-ing lugs to tow the vehicle from the water ontoland.

100. Methods of Rigging

The methods of rigging for underwater recoverynormally are restricted to the manpower and leadmethods. The backup method may be used onlywhen the recovery vehicle is on the shore line, orin very shallow water. The method of riggingemployed depends upon distance from winchingsource to disabled vehicle, type of disabled ve-hicle, type of recovery vehicle used, amount ofequipment available (floats, boats, and ropes,etc.), and condition of the disabled vehicle.

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a. Lead Method. The lead method of rigging isaccomplished in the same manner as on land;however, some modification of the preparationmust be made when the hoist winch rigging istransported through or on the water to the objectof recovery. The hoist winch cable and snatchblock can be manually transported on the riverbottom if the distance is not too great, and un-derwater visibility is good enough for divers tokeep the disabled vehicle in sight at all times.With a power boat available, two divers will beable to lead the hoist winch cable and transportthe snatch block to the object of recovery (fig113). A similar fording-type vehicle can be usedto transport the main winch rigging to a disabledvehicle, providing the condition of the river bot-tom would permit its use.

Figure 113. Transporting hoist winch cable to vehicledisabled under water.

b. Manpower Method. The manpower method

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of rigging is acomplished in the same manneras discussed in paragraph 29a. A winch cable canbe transported to a floating or submerged dis-abled vehicle by using a series of floats to supportthe cable on the water (fig 114) or attaching arope to the cable end, swimming with the rope tothe object of recovery, and then pulling the cableto the vehicle.

Figure 114. Floating winch cable to object of recovery.

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APPENDIX A

REFERENCES

1. Field Manuals (FM)

21-5 Military Training.21-6 Techniques of Military In-

struction.21-30 Military Symbols.

2. Army Regulations (AR)

310-25 Dictionary of United StatesArmy Terms.

310-50 Authorized Abbreviationsand Brevity Codes.

3. Technical Manuals (TM)

5-725 Rigging:9-2320-211-10 Operator's Manual For 5-

Ton 6x6 Truck, Chassis:M39, M40, M40C, M61,M61A2, M63, M63A2,M63C, M139, M139C,M139D, M139F,M139A2F; Truck, Car-go: M41, M54, M54A1,

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M54A2, M55, M55A2;Truck, Dump: M51,M51A2; Truck, Tractor:M52, M52A1, M52A2;Truck, Tractor, Wreck-er: M246; Truck, Van:Expansible, M291A2,M291A2C; Truck,Wrecker, Medium,M62, M543, M543A2.

9-2320-222-10 Recovery Vehicle, FullTracked, Medium M88.

9-2320-238-10 Recovery Vehicle, FullTracked, Light, ArmoredM578.

4. Miscellaneous

DA Pam 310-3 Index of Doctrinal, Train-ing, and OrganizationalPublications.

DA Pam 310-4 Index of Technical Manu-als, Technical Bulletins,Supply Manuals, SupplyBulletins, and Lubrica-tions Orders.

ASubjScd 5-5 Rigging.ASubjScd 9-20 Practical Application-

Ordnance RecoveryPersonnel.

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INDEX

Paragraph Page

Anchors .-. . ...................... 26 36Mechanical anchors ----------- 28 36Natural anchors --------------- 27 36

APCAT (armored personnel carrieranchoring track) device -------- 64c 81

Blocks, classification by usage:Fixed block ------------------- 15a 24Running block ---------------- 15b 26

Blocks, types by construction:Conventional block - . ....14a 22Mechanical advantage of tackle 17 28Snatch block -........... 14b 22

Capstan winching of armored person-nel carrier ---------------------- 65 84

Effort versus resistance ------------ 10 17Equipment strength ---------------- 22 31

Fiber rope -------------------- 23 31Wire rope and chain ---------- 24 34

Estimating resistance of vehicles dis-abled by terrain:

Grade resistance ..- . ........... 6a 9Mired resistance -------------- 6c 9Overturning resistance . 6b 9

Expedient repairs:Broken distributor point spring _ 74 97Broken fan belt - __-.. __. ..__- 80 102Broken fan blades ------------- 81 102

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Paragraph Page

Cracked low-pressure oil or fuellines ....................... 77 100

Damaged front axle brake system 79 102Damaged road wheel components_ 84 106Damaged suspension components_ 85 107Damaged wheel --------------- 71 95Defective differential 73 97Disabled tandem axle .-.... 72 95Leaking low-pressure line fitting_ 76 100Loose battery clamp - 75 99Punctured fuel tank ---------- 82 103Punctured tube-type radiator

core ------------------------ 78 100Repairs by crewmen -. . ....... 70 92Shearpin substitute ------------ 83 103

Helicopter recovery of mired vehicles. - 69 88Levels of recovery:

Company and battalion level ___ 4b 6Platoon level ----------------- 4a 6

Leverage:Leverage principle -.---------- 11 17Lever classification ------------ 12a 18

Locating submerged vehicles ------- 12b 20Mechanical advantage ------------- 98 125Methods of recovery:

Expedients --------------- - - 3d 5Lifting ----------------------- 3c 5Towing -3b 5Winching ...-----------... 3a, 55b, 5, 65,

62 74

Methods of rigging:Backup method --------------- 29b 42Lead method -.------------- 29c, 100a 45,128Manpower method -.. - 29a, 100b 42, 128Methods of attachment ..- . ... 30,99 46, 126

Mired tracked vehicles ------------ 91 115Mired truck ----------------------- 87 108Nosed tracked vehicles ------------- 92 117

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Paragraph Page

Nosed truck ----------------------- 88 110Overturned tracked vehicles -------- 93 118Overturned truck ------------------ 89 110Recovery expedients-5 .- 6.... 59 72

Anchoring tracks -------------- 64 77Moving tracked vehicle, with both

tracks broken - .------ 66 86Moving vehicle onto a track ___ 67 87Substitute for a jack ----------- 60 72Use of a pry -.. -------- 61 74Use of wheels for winching ---- 62 74Use of an A-frame ------------ 63 76

Recovery procedure ---------------- 45-53 58-62Reinstalling a thrown track -------- 68 87Resistance .----------------------- 5 7

Tackle resistance ------------- 18 29Total resistance - .------- 19 30

Resistance reducing factors -------- 7 10Rigging -------------------------- 16 27Safety --------------------------- 31 48

Care of cables _ 33 49Crossed lines 38 55Fuel or oil spillage ------------ 39 55Handling cables --------------- 32 49Hooked position --------------- 34 51Impact loads -- -------------- 44 57Inspecting rigged equipment -_ - 37 54Operator/driver safety -------- 41 56Positioning gun tubes - .--- -.. 40 55Rigging between vehicles _ ----- 36 53Safe location of personnel ..- 42 56Safety keys ------------------- 35 51Signalman -.- .. ............ 43 56

Sling leg forces ----............... 25 35Sources of effort-similar vehicles _ 8, 97a 12, 124Sources of effort-winches 9, 97b 12, 125Special purpose vehicles . 86 108

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Paragraph Page

Tackle:Compound tackle .------------- 13b 20Dead line --------- ___..------ 16c 27Dead line force ................ 21 30Fall line ------------ ______---- 16a 27Fall line force ................ 20 30Return line ------------------- 16b 27Simple tackle -------- __.__.__ 13a 20

Towing tracked vehicles ---------- 94 119Towing wheeled vehicles ------ - 90 111Underwater vehicle recovery:

Floating type vehicles --------- 96a 123General -------------------- 95 122Load resistance in water __.. _ 96 122Non-floating type vehicles ..- .. 96b 124

Vehicle recovery operations:General ----------------------- 54 63Towing disabled tracked vehicles. 58 71Towing disabled- wheeled vehicles 56 67Use of similar-type tracked ve-

hicle for recovery ----_____ __ 57 67Use of similar-type wheeled ve-

hicle for recovery ----___. ___ 55 64

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By Order of the Secretary of the Army:

W. C. WESTMORELAND,General, United States Army,

Official: Chief of Staff.KENNETH G. WICKHAM,Major General, United States Army,The Adjutant General.

Distribution:

To be distributed in accordance with DAForm 12-11 requirements for Vehicle RecoveryOperations.

.:U.S. GOVERNMENT PRINTING OFFICE: 1981-361-647:2860