How To Barbed Wire Fence Installation
LESSON 4
BARBED WIRE ENTANGLEMENTS
LESSON OBJECTIVES
Upon completion of this lesson on Barbed Wire Entanglements, you should be able to achieve the following in the indicated topic areas:
ane. Purpose. Describe the two purposes of the employ of barbed wire entanglements.
2. Siting and Layout. State the 5 requirements for constructive siting and layout of barbed wire entanglements.
3. Classification — by Utilise. Describe the 3 classes of entanglements — tactical, protective, and supplementary.
4. Classification — past Depth. Describe the 3 types of entanglements — belt, ring, and zone.
5. Barbed Tape. State the advantages and disadvantages of spinous tape.
6. Material and Labor Estimates. Guess the manhours and material needed to construct tactical, protective, and supplementary entanglements of a defensive position.
7. Uses. Describe the seven uses of entanglements — outpost expanse, battle position, artillery area, reserve area, antipersonnel obstacles, roadblocks, and to strengthen material obstacles.
8. Pickets and Ties. Describe types and uses of pickets and ties.
9. Fences. Depict fences to include four strand cattle fence, double apron fence, standard concertina fence, and triple standard concertina fence.
10. Portable Barbed Wire Obstacles. Draw the portable spinous wire obstacles and their uses.
ATTACHED MEMORANDUM
Section I. Materials
4-1. CONCEPT
a. Purpose. Spinous wire entanglements are artificial obstacles designed to impede the movement of human foot troops and, in some cases, tracked and wheeled vehicles. The materials used in constructing spinous wire entanglements are relatively lightweight and inexpensive, considering the protection they afford. Barbed wire entanglements tin can be breached by fire only are built rapidly, repaired, and reinforced.
b. Siting and layout. To be effective, barbed wire entanglements are sited and laid out to see the following requirements:
(1) Under friendly ascertainment, covered by fire, and where practicable, protected by antipersonnel mines, flame mines, tripflares, and warning devices.
(two) Curtained from enemy observation as far as practicable by incorporating terrain features such every bit reverse slopes, hedges, woods, paths and fence lines.
(3) Erected in irregular and non-geometrical traces.
(iv) Employed in bands or zones wherever practicable.
(five) Coordinated with other elements of the defence force.
c. Nomenclature. Entanglements are classified according to their use, their depth, and whether fixed or portable.
(1) Use. Entanglements are classified by use every bit tactical, protective, or supplementary. The employment of these types in a defensive surface area is shown schematically in effigy 4-1.
(a) Tactical. Tactical wire entangle-ments are sited parallel to and forth the friendly side of the final protective line. They are used to pause upwardly enemy attack formations and to concord the enemy in areas covered past the nearly intense defensive burn down. Tactical entanglements extend across the unabridged front of a position merely are not necessarily continuous.
(b) Protective. Protective wire entanglements are located to prevent surprise assaults from points close to the defence expanse. Equally in the example of all antipersonnel obstacles, they are close enough to the defense surface area for 24-hour interval and night ascertainment and far enough away to prevent the enemy from using hand grenades effectively from points merely beyond the obstacle, ordinarily 40 to 100 meters (131 to 328 ft.). Protective wire surrounds the private units of a control, commonly the platoons (fig four-2). These entanglements should be continued to entanglements effectually other platoons past supplementary wire to enclose the entire defensive positions. Protective entanglements are erected around rear-area installations in the same fashion and to serve the same purpose as protective wire around defensive positions in forward areas. Protective wire also includes the entanglements which should exist installed over the tops of installations provided with overhead embrace (fig 4-2).
Figure 4-1. Schematic layout of barbed wire entanglements in a defensive area.
Effigy 4-2. Protective wire on top of overhead embrace.
(c) Supplementary. Supplementary wire entanglements in front of the forward edge of the battle expanse are used to muffle the exact line of the tactical wire. To the rear of the FEBA, supplementary wire is used to enclose the entire defensive position past connecting the protective wire entanglements. Supplementary wire entanglements used to intermission upwards the line of tactical wire should be identical to the tactical wire entanglements and synthetic simultaneously with them whenever possible.
(2) Depth. Entanglements are classified by depth as belts, bands, or zones.
(a) Chugalug. A belt is an entanglement 1 debate in depth.
(b) Band. A band consists of two or more belts in depth, with no interval between them. The belts may be fences of the aforementioned type, or the ring may exist equanimous of 2 or more fences of different types.
(c) Zone. A zone consists of two or more than bands or belts in depth, with intervals between them.
(3) Equivalent effectiveness. Entanglement depths are also described or specified in terms of comparative effectiveness. Tactical wire entanglements should exist equivalent in effectiveness to three belts of four- and 2-pace double frock fence whenever possible. Protective wire may employ any type of entanglement provided its effectiveness is at least the equivalent of that of the 4- and 2-footstep double frock fence. Supplementary wire should have an effectiveness equivalent to that of the blazon of wire it supplements. It should exist equivalent to tactical wire or equivalent to the blazon of protective wire being used if it connects the outer perimeters of protective wire at the flanks and rear.
(4) Portability.
(a) Stock-still entanglements are those types which must be erected in identify and which cannot be moved unless completely disassembled.
(b) Portable entanglements are those types which tin exist moved without complete disassembly. Portable entanglements accept been developed for one of the following reasons: To allow associates in rear areas, with ease of transportation and rapid installation in forward positions. For the temporary endmost of gaps or lanes which can exist reopened quickly for patrols or counterattacking forces.
d. Lanes and gaps. Lanes and gaps are provided for the passage of patrols, working parties, and attacking or counterattacking forces. When not in use they are kept closed by the use of portable obstacles covered by fire. In barbed wire zones, lanes and gaps are staggered in a zigzag pattern.
e. Uses.
(1) Outpost area. Combat outposts should exist surrounded with wire entanglements. These entanglements should exist carefully sited to serve every bit both protective and tactical wire and must be covered by small arms fire. The wire obstacle should be supplemented past antipersonnel mines, alert devices, and booby traps.
(2) Battle position. In the boxing area, each company defense force position is commonly surrounded by a wire entanglement which is continued laterally across the forepart to the entanglements surrounding the other units in the position.
(three) Artillery and reserve expanse. Wire entanglements are used in the outer protection of howitzer positions. Heavier weapons, and shelters or other installations in the reserve area, are similarly protected if justified past the state of affairs.
(iv) Antipersonnel obstacles. Barbed wire entanglements, tripflares, noisemakers, and antipersonnel mines are sited to warn confronting enemy patrol activeness or infiltration at night; to forestall the enemy from delivering a surprise attack from positions shut to the defenders; and to hold, fix or delay the enemy in the most effective killing ground. Such obstacles should be near enough to defensive positions for acceptable surveillance by the defenders by nighttime and day and far enough away to forbid the enemy from using hand grenades confronting the defender from points just beyond the obstacles.
f. As roadblocks. A series of barbed wire concertinas as shown in figure 4-iii will stop wheeled vehicles. A series of these concertinas should be placed in blocks most ten meters in depth. The ends of adjacent coils are wired together and the obstacle lightly anchored at the sides of the road. The block should be sited to reach surprise.
chiliad. To strengthen natural obstacles. Deep rivers, canals, swamps, and cliffs which form effective delaying obstacles to infantry, and thick hedgerows, fences, and wood, which are only fractional obstacles, tin exist improved by lacing with barbed wire, past the improver of parts of standard fences on one or both sides, or by entangling with loose wire.
Figure 4-3. Concertina roadblock.
4-ii. STANDARD Barbed WIRE
a. Description. Standard spinous wire is 2-strand twisted No. 12 steel wire with 4-signal barbs at 10 cm (4 in.) spacing (fig 4-4).
b. Handling. In handling barbed wire, the standard barbed wire gauntlets shown in effigy 4-four or heavy leather gloves are worn. They permit faster piece of work and avert cuts and scratches. Every bit an added condom precaution, the wire should be grasped with the palm downward.
c. Upshot. Spinous wire is issued in reels (fig four-5) containing well-nigh 400 meters (1312 ft.) of wire. The wire weighs 40.viii kg (90 lb.) and the reel 0.6 kg. In building a argue, two men carry one reel.
d. Bobbins. Bobbins (fig iv-6) holding nigh 30 meters (98 ft.) of wire are prepared, normally in rear areas, for use in building short lengths of fence and in repairing entanglements. In utilise, two men handle one bobbin. 1 unwinds the bobbin while the other installs the wire. Ii or more men may make the bobbins every bit follows:
Figure 4-four. Standard spinous wire.
Figure iv-5. Barbed wire reel.
Figure 4-vi. Barbed wire bobbin.
(1) The bobbin sticks are prepared.
(2) The reel is rigged on a improvised trestle or other support.
(three) I human being unrolls and cuts 30-meter (98 ft.) lengths of wire. One cease of each piece is attached to the trestle.
(4) The wire is wound in figure-viii shape on the bobbin sticks.
(5) A slice of white tracing tape should be tied to the loose end of the wire to facilitate finding information technology.
4-three. Spinous STEEL TAPE
a. Characteristics. The physical characteristics of barbed record (fig. four-7) are every bit follows:
Width: three/4 inch (1.91 cm)
Thickness: 0.222 (.056 cm)
Weight: iv.438 lb/fifty meters (/164 Ft)
Width of barb: 7/16 inch (1.11 cm)
Interval between barbs: l/ii inch (1.25 cm)
Breaking load: 500 lb. (1111 kg)
b. Handling. In handling spinous tape, heavy barbed tape gauntlets should be used instead of the standard gauntlets. Small metallic clips on the palm and fingers prevent the barbs of the tape from cutting the leather (fig. iv-8). The light weight of the barbed tape and compactness, it is much easier to handle, store, and transport than barbed wire.
c. Issue. Spinous tape is issued in fifty-meter (164 ft.) reels weighing 2.4 kg. There are 6 reels to a cardboard conveying case.
d. Spinous record dispenser. A dispenser (fig. 4-viii) is required to install barbed tape. Information technology consists of a frame to agree the fifty-meter (164 ft.) reel of barbed tape and two sets of rollers. The reel is inserted on the spindle and the tape is threaded through the two sets of parallel rollers. The outside set of rollers are and then turned 90� in a clockwise direction. The hinged arm of the frame is and so closed and locked in place by the frame of the rotating rollers. As the tape unwinds from the reel, the two sets of rollers oriented 90� to each other impart a twist to the tape. To exist effective the barbed tape must be twisted as it is installed.
Figure four-7. Spinous steel tape.
Two significant characteristics shown higher up which are important to field users are the weight and the breaking load. A comparing of pertinent characteristics of spinous tape and barbed wire is shown beneath.
e. Uses. Barbed tape can exist used in place of standard barbed wire in most all cases except when it is to be repeatedly recovered and reused. The about effective fence that can be constructed using barbed record is the double-apron fence.
(1) The principal advantages of barbed tape are its size and weight. For equal lengths, barbed tape occupies a third of the space and weighs a 3rd as much every bit standard barbed wire. A double-apron fence constructed with barbed tape is more difficult to breach by crawling through than one constructed with standard barbed wire because the barbs of the barbed tape are closer together. Because of the flat configuration, information technology is more than difficult to cutting barbed tape with wire cutters.
(2) At the present time, the major disadvantage of barbed record is the breaking force. Standard barbed wire is twice equally strong. Installation of barbed tape requires a dispenser. A major trouble could arise if the dispenser is not available. The tape is not recoverable to its original condition. Even so, it may exist recovered on bobbins in the twisted status. Spinous tape is more hands cut by vanquish fragments than standard barbed wire. Spinous tape can also be cut with a bayonet.
Effigy 4-viii. Spinous tape equipment.
f. Double-apron debate. The standard double-apron fence is one of the best obstacles that tin can exist fabricated with spinous tape; and the effectiveness of this obstacle is increased by —
(1) Raising the top wire to preclude crossing the obstacle by stepping over information technology.
(2) Placing low wires 4 inches above basis to prevent personnel from crawling nether the obstruction.
m. Tying procedures. In tying spinous tape the wrap-around tie (fig. 4-7) should exist used, since the sharp bends of other ties weaken the record. Steel wire rings, crimped on, provide effective ties and may be used where available (fig. 4-8).
h. Splices. Connecting slots at each end of a l-meter (164 ft.) reel provide a quick method of splicing reels of barbed tape (fig. four-9). Barbed tape may also be spliced by interlocking the twisted barbs of two separate lengths, and so completing the splice by affixing one steel wire ring to each end of the area where spliced (fig. 4-9).
Effigy 4-9. Splicing barbed steel tape.
4-4. PICKETS
Wire entanglements are supported on metallic or woods pickets.
a. Metal pickets. Metal pickets are issued in two types, screw and U-shaped. The standard lengths are short or anchor, medium, and long (fig. 4-10). The U-shaped sentry also comes in an extra long length. Pickets that are serviceable are recovered and used once more.
(1) Screw picket. The screw sentinel is screwed into the ground by turning it in a clockwise direction using a driftpin, stick, or some other picket inserted in the bottom centre of the picket for leverage. The bottom eye is used in social club to avert twisting the picket. Screw pickets are installed so the eye is to the right of the lookout, as seen from the friendly side so standard ties to be made easily. Screw pickets tend to be less rigid than other types but are desirable because they tin be installed rapidly and silently. When silence is necessary, the driftpin used in installing the pickets should be wrapped with cloth.
Figure 4-10. Pickets for use with barbed wire.
(2) U-shaped picket. U-shaped sentry is a cold-formed steel sentry of U-shaped cross section, pointed at one end for driving. It is notched for wire ties and the pointed end has a punched pigsty for wires used in bundling the pickets. U-shaped pickets are driven with a sledge hammer. A stake driving cap is used on top of the lookout to prevent a sledge from deforming it. Driving the pickets is noisier than installing screw pickets. Racket may exist reduced by placing a piece of prophylactic tire over the driving face of the sledge. The pickets are rigid and sturdy when properly installed and are preferable to screw pickets in situations where noise is not a disadvantage and time is bachelor. The pickets are driven with the hollow surface or concave side facing enemy burn down because minor arms projectiles ricochet from the convex side. An expedient picket driver which can be locally made is shown in figure 4-11. Constructed as shown it weighs approximately 12 kilograms and is operated by two men. One human holds the picket in a vertical position while the other slides the driver over the picket and starts it into the ground. And then, both men work the picket driver up and down until the required depth is reached. Short pickets tin can be driven by turning the lookout driver upside down and using the head equally a hammer. The bucket of a front loader can be used to push U-shaped pickets into the basis if the tactical situation permits the employ of equipment.
Figure four-eleven. Expedient scout driver .
(iii) Arctic adapter. For erecting barbed wire obstacles with U-shaped drive pickets under conditions where frozen basis prevents driving the pickets, an Arctic adapter is available for anchoring the pickets. The adapter is made of steel and consists of a base plate equipped with an adjustable channel receptacle and 2 ballast pins. Information technology is anchored past driving the anchor pins through holes in the base place into the basis. 1 anchor pin drive sleeve with driving pivot is provided with each 20 adapters to facilitate anchor pin emplacement. When adapters are not bachelor, a hole can exist started with a selection and the lookout man tin exist frozen in place by pouring water and snow into the hole.
b. Wooden picket. Expedient wooden pickets of several types may exist used.
(1) Circular poles 10 cm (four in.) in diameter are cut to standard scout lengths, sharpened on i end, and driven with a maul. The pickets are used without peeling the bark to prevent the wire from sliding on the sentry and to simplify camouflage. Longer pickets are required in loose or sandy soil or when driving through a snow encompass. The driving of wooden pickets is not as noisy as the driving of steel pickets, and the noise can exist reduced further by fastening a department of tire tread over the face of the hammer or maul. For driving in difficult world, lookout man tops are wrapped with wire to avert splitting. Pickets of hardwood, properly installed, are sturdy and rigid.
(two) Dimension lumber ripped to a square cross department may be used instead of circular poles. This is equally satisfactory except that is more difficult to camouflage. Such pickets may be camouflaged by painting prior to driving.
(3) Standing trees and stumps may be used as pickets when their location permits.
c. Reference. Table four-1 lists information pertaining to materials used in the structure of barbed wire entanglements.
four-5. CONCERTINA FENCING
a. Standard barbed wire concertina. The standard barbed wire concertina (fig. 4-12) is a commercially manufactured barbed wire obstruction fabricated of a coil of single-strand, loftier-force, bound-steel wire with iv-point barbs attached at 5 cm (2 in.) spacing. Wires forming the coils are clipped together at intervals and then the concertina opens to a cylindrical shape 5 to xv meters (sixteen.4 to 49.2 ft.) long (depending on structure and build of opening) and 90 centimeters (iii ft.) in diameter. The 5-meter (sixteen.4 ft.) length prevents smaller enemy personnel from crawling through the wire every bit the coils are closer together. Tanglefoot should besides be employed in conjunction with the wire to further increment the barrier's effectiveness. The concertina is easily opened and collapsed and tin can exist used repeatedly considering the wire returns to its original shape after a burdensome forcefulness is practical and and so removed. The wire is much harder to cut than standard barbed wire. The concertina weighs 25.4 KG (55.viii lb).
Table 4-1. Wire and Record Entanglement Materials
Figure 4-12. Standard barbed wire concertina.
(1) Handling.
(a) To open concertina. The collapsed concertina is tied with plain wire bindings attached to the quarter points of a whorl at 1 end of the concertina. In opening the concertina, these bindings are removed and twisted around the carrying handle for use in tying the concertina when it is once more collapsed. Four men open a concertina and extend information technology to the five- to 15-meter (sixteen.4 to 49.ii ft.) length, with one man working at each end and others spaced along its length to insure it opens and extends evenly. When necessary, ii men can easily open a concertina by billowy information technology on the ground to prevent snagging as they open information technology.
(b) To collapse concertina. Two men tin can plummet a concertina in the following style: Commencement all kinks in coils are removed. Loose clips are and so tightened or replaced with plain wire. To close the concertina, i human stands at each end of information technology and places a pes at the bottom of the coil and an arm under the height of the coil. The two men walk toward each other closing the concertina past feeding the wire over their arms and against their feet. When closed, the concertina is laid flat and compressed with the feet. The concertina is tied with plain wire bindings.
(c) To bear concertina. One homo easily carries the collapsed concertina by stepping into it and picking information technology upwardly by the wire handles fastened to the midpoints of an cease coil.
(2) Staples. Improvised staples approximately 45 cm (xviii in.) long and made of fifty/2 inch (1.25 cm) driftpins or like fabric are used to spike the bottoms of concertina fences securely to the footing.
b. Barbed steel record concertina. Barbed tape concertina comes in a bore of 85 cm (33 in.) and an expanded length of 15.two meters (50 ft.). It is formed of spinous tape wrapped around a high strength, jump steel, cadre wire. Its configuration, method of handling, and method of employment are like to standard barbed wire concertina. One roll weighs only 14 kg (31 lbs.).
Section 2. Structure Procedures
4-6. Organization of Work
Table four-2 gives the materials and manhours required for entanglements of the various types. The normal sizes of piece of work crews are given in the descriptions of the entanglements. For each construction project, the senior noncommissioned officer divides his crew into groups of approximately equal size, based on his noesis of the skill and speed of each homo. He organizes them in such a way that structure gain in proper order and at a uniform rate. Each individual must know exactly what his group isto practice and his particular job in the group. Each homo should take barbed wire gauntlets. The sequence of operations for each fence is given in the paragraph describing the erection of the contend. The sequence that is outlined should be followed, and as experience is gained, the size and composition of the groups may be varied. For each section of entanglement, all fence-building operations normally proceed from right to left, as one faces the enemy. Information technology may exist necessary under some circumstances to work from left to right. If time permits, men should be taught to work in either management. In case of heavy casualties, the senior officer or NCO will decide what wires, if any, are to exist omitted.
Table 4-2. Material and Labor Requirements for 300 Meter Sections of Diverse Wire Entanglements.
a. Structure at night. For night structure the following additional preparations are made:
(i) Tracing record should be laid from the materials dump to the site of piece of work and and then along the line of debate where possible.
(2) Materials should be tied together in man loads, and pickets bundled tightly to forbid rattling.
(3) Wire fastenings of wire coils and pickets should be removed and replaced with string which can be cleaved easily.
(4) A piece of tape should be tied to the ends of the wire on each reel or bobbin.
b. Supervision. Proper supervision of entanglement construction includes the following:
(ane) Proper organization of the work into tasks.
(2) Making sure the tasks are carried out in the proper sequence.
(3) Prevention of bunching and overcrowding of personnel.
(4) Making sure the wires are tightened properly and spaced correctly.
(5) Checking ties to verify that they are being made correctly and at the correct points.
c. Construction in combat areas. When working in close proximity to the enemy, the necessary precautions include—
(1) Provision of security around the piece of work political party.
(2) Silence.
(3) No working on enemy side of debate unless absolutely necessary.
(4) Utilise of screw pickets, if available.
(5) Men non working should seek concealment near the work site until they begin work.
(6) Individual weapons must be kept nearby at all times.
d. Wire ties. Wires are tied to pickets past men working from the friendly side of the wire and sentry; the wire is stretched with the correct mitt as the tie is started. The four ties used in erecting wire entanglements are shown in effigy four-xiii.
Figure 4-xiii. Ties for erecting entanglements as seen from the friendly side.
(1) Superlative-eye tie. The height eye is used to fasten standard spinous wire to the summit eye of screw pickets. Information technology is made in ane continuous movement of the left hand (fig 4-xiv) while the right hand exerts a pull on the fixed end of the wire. This is a secure tie, quickly fabricated, and uses simply a short slice of wire.
Figure 4-xiv. Top-centre tie.
(2) Intermediate-eye tie. This tie is used to spike standard barbed wire to eyes other than the top center, in screw pickets. It is made as shown in figure 4-15. This tie and the other ties described beneath require more time to make than the top-eye necktie and each uses several centimeters of wire. In making the intermediate-centre shown in effigy 4-15, the following points are particularly of import:
(a) The right hand reaches over the fixed wire and around the lookout, with the palm down. The left mitt holds the fixed finish for tension.
(b) The loops are removed from the costless terminate and wrapped around the lookout.
(c) I side of the loop should laissez passer to a higher place the heart and the other side below the eye.
(3) Post tie. Standard spinous wire is attached to wooden pickets or to the steel U-shaped spotter with the postal service tie shown in effigy 4-16. The wire should be wrapped tightly effectually the post to keep the barbs from sliding down. With the U-shaped lookout, the wire wrapping is engaged in a notch in the picket. The method is substantially the same as that of the intermediate-middle necktie.
(four) Apron tie. The frock necktie is used whenever ii wires that cross must exist tied together. It is tied in the aforementioned fashion as the mail tie except a wire is substituted for the postal service (fig. 4-17).
(five) Spinous tape splices. Connecting slots at each end of a 50-meter (164 ft.) reel provide a quick method of splicing reels of barbed tape. Barbed tape may also exist spliced by interlocking the twisted barbs of two divide lengths, then completing the splice by twisting a brusk piece of wire to each end of the area where spliced.
e. Method of installing wires
(ane) The end of the wire is fastened to the showtime anchor picket. This is the picket at the right end of a section of entanglement, from the friendly side. Fences are built from right to left as this makes it easier for a correct-handed human being to brand the ties while remaining faced toward the enemy.
(ii) A bar is inserted in the reel and the reel is carried for 23 to 27 meters (75 to 88 ft.), allowing the wire to unwind from the lesser of the reel. This is washed on the friendly side of the row of pickets to which the wire is to be tied.
(3) Slack is put in the wire past moving back toward the starting point; the ties are then made by 2 men leapfrogging each other. If available, two men can be assigned to make the ties as the reel is unwound.
f. ;Tightening wire. Subsequently a wire is installed information technology tin be tightened, if necessary, by racking with a driftpin or brusk stick (fig. four-xviii). Wires should non exist racked at ties or where they intersect other wires because this makes salvage of the wire very hard. Fences are similarly racked to tighten them when they sag after having been installed for some time. Wires should be just taut enough to prevent them from being depressed easily by boards, mats, or like objects thrown across them. If wires are stretched too tightly they are more than easily cutting by fragments. Barbed steel record must never be tightened by racking.
Figure 4-15. Intermediate-centre tie.
Figure 4-xvi. Postal service tie .
4-seven. FOUR-STRAND CATTLE FENCE
a. Clarification. The four-strand middle section of a double apron fence can be installed apace to obtain obstruction result, and aprons can be added afterwards to develop information technology into a double apron fence. In rural areas where wire fences are used by farmers, obstacles in the form of 4-strand cattle fences (fig. iv-xix) will alloy with the landscape. Their blueprint should follow as closely every bit possible the local custom, usually wooden pickets at about 2- to four-stride intervals with four horizontal strands of barbed wire stock-still to them. They should be sited forth footpaths and edges of fields or crops, where they volition not expect out of place. If conditions permit, this contend may be improved by installing guy wires in the aforementioned manner as the diagonal wires of the double apron argue. All longitudinal wires of this debate must start and end at an ballast picket.
b. Construction. Eight men may be employed on brusk sections of this fence up to xvi men on 300-meter (984 ft.) sections.
Figure 4-17. Standard barbed wire frock tie.
Effigy four-xviii. Tightening wire by racking.
The ii operations are laying out and installing pickets, and installing wire.
(1) First operation. The work party is divided into two groups of approximately equal size. The outset group carries and lays out long pickets at iii-meter (ix.8 ft.) intervals along the centerline of the fence, beginning and catastrophe the department with an ballast lookout man, and including anchor pickets for guys if needed. The 2d group installs the pickets.
Effigy 4-nineteen. Four-strand cattle fence as viewed from the enemy side.
(2) Second performance. As the first task is completed, men motility individually to the head of the fence and are organized into teams of 2 or four men to install wires. Four four-homo teams, two men carry the reel and two men make ties and pull the wire tight. For two-man teams, the wire must first exist unrolled for l to 100 meters (164 to 328 ft.), so the men come back to the head of the work and brand the ties or the wire may start be made upward into bobbins to be carried and unwound by one homo while the other man makes the ties. The commencement team installs the lesser argue wire, and draws it tight and close to the basis. Succeeding teams install the next wires in lodge.
4-8. DOUBLE-Apron FENCE
a. Types. There are two types of double apron fence, the iv- and two-pace debate and the 6- and three-pace fence. The four- and two-pace fence (fig. iv-20) is the amend obstacle of the two and is the type more unremarkably used. In this fence the center pickets are four paces apart and the anchor pickets are two paces from the line of the center pickets and opposite the midpoint of the infinite between heart pickets. The 6- and three-pace debate follows the same blueprint with pickets at 6- and 3-step intervals. For this contend, less fabric and structure time are required, only the obstacle outcome is substantially reduced because with the longer wire spans make it is easier to raise or lower the wires and crawl over or under them. Except for lookout spacing, the 4- and 2-pace and the 6- and 3-pace fences are identical. Simply the iv- and ii-pace contend is discussed in detail.
Figure four-20. Double apron fence.
b. Construction. A 300-meter (984 ft.) section of either blazon of double-apron fence is a platoon job commonly requiring 1 l/2 hours, assuming 36 productive men per platoon. There are two operations in edifice a double apron fence: laying out and installing pickets, and installing wire. The get-go functioning is nearly completed prior to starting the second. The second operation is started every bit men become bachelor and the first operation has moved far enough ahead to avoid congestion. A platoon is normally assigned to build a 300-meter (984 ft.) section.
(ane) Starting time performance. The work party, if non organized in three squads, is divided into three groups of approximately equal size. Ane squad lays out the long pickets along the centerline of the fence at 4-pace intervals at the spots where they are to exist installed and with their points toward the enemy. Another squad lays out the anchor pickets, with points toward the enemy and positioned ii paces each style from the centerline and midway between the long pickets (fig. iv-21). The spacing is readily checked with a long picket. The 3rd squad installs all the pickets, with the assistance of the two other squads as the latter finish the work of laying out the pickets. When installed, the lower notch or bottom eye of the long pickets should be judge 10 cm (four in.) off the ground to make passage difficult either over or nether the bottom wires.
Figure 4-21. Laying out anchor pickets.
(ii) 2nd operation. As the groups complete the outset operation, they return to the head of the argue and brainstorm installing wire. The guild in which the wires are installed is shown in figure iv-20 and is farther illustrated in figure 4-22. Care must be taken to avoid having whatsoever of the men cut off between the fence and the enemy. The men are divided into two- or 4-man groups and proceed to install the wires in numerical guild; that is, as soon as the men installing one wire have moved away from the offset of the argue and are out of the way, the next wire is started. Installation is equally follows:
(a) The No. 1 wire is the diagonal wire on the enemy side and is secured with a top-eye tie to all pickets. It is important to keep this wire tight.
(b) The No. 2 wire is the trip wire on the enemy side of the contend and is secured to both diagonals but higher up the anchor spotter with the apron tie. This wire must exist tight plenty and close enough to the ground to make passage over or under the wire hard.
Figure four-22. Sequence of installing wire in a double frock contend.
(c) The No. three wire is an apron wire on the enemy side of the fence. It is secured to the starting time diagonal wire, and thereafter to each alternate diagonal, and then to the last diagonal wire. The No. 4 wire is also an apron wire on the enemy side of the debate. It is secured to the start diagonal wire (No. one), thereafter to the diagonal wires which are non tied to the No. iii wire, so to the last diagonal wire. Apron wires Nos. 3 and 4 are equally spaced forth the diagonal wire.
(d) The No. 5 wire is the first i which is non started from the cease anchor lookout man. It is started at the starting time long watch, and ended at the final long sentry. Information technology is secured with the intermediate-eye necktie and is stretched tightly to forestall passage over or under it.
(e) Wires No. half-dozen, 7, and 8 complete the center portion of the fence and are secured to the long picket No. six and 7 with the intermediate-eye tie. They besides start at the first and cease at the last long watch. No. eight is secured with the top-eye ties. These wires (No. half-dozen, vii, and eight) for the backbone of the debate and are drawn upwardly tightly to concur the pickets in position.
(f) No. 9 is the diagonal apron wire on the friendly side of the fence and is secured with the elevation-eye to all pickets. No. 10 and 11 are apron wires and No. 12 is the tripwire on the friendly side of the argue. Wire No. 12 is installed in the same manner as wire No. 2 (b) above).
(m) If the fence is not satisfactorily tight when installed, wires are tightened by racking as described in paragraph four-6f.
4-9. STANDARD CONCERTINA FENCES
As an obstacle, in virtually situations, the triple standard concertina contend is better than the double apron argue. The material for the standard concertina fence weighs almost fifty percentage more than for a triple standard concertina fence of the same length, merely information technology is erected with most half the man-hours. Every concertina contend is secured firmly to the footing past driving staples at intervals not more than two meters (6.6 ft.). The staples are used on the single concertina fence and on the front concertina of the double and triple types. The two types of argue are as follows:
a. Single concertina. This is i line of concertinas. Information technology is erected quickly and easily but is not an effective obstacle in itself. It is used as emergency entanglement or for the temporary closing of gaps between other obstacles. It is for such purposes that ane roll of concertina may exist habitually carried on the front of each vehicle in gainsay units.
b. Double concertina. This consists of a double line of concertinas with no interval between lines. The two lines are installed with staggered joints. As an obstacle, the double concertina is less effective than a well-emplaced, double apron fence. It is used in some situations to supplement other obstacles in a band or zone.
iv-ten. TRIPLE STANDARD CONCERTINA FENCE
a. Clarification. This consists of two lines of concertinas serving as a base, with a third line resting on top, equally shown in figure iv-23. All lines are installed with staggered joints. Each line is completed before the next is started so a partially completed concertina entanglement presents some obstruction. It is erected rapidly and is hard to cantankerous, cut, or clamber through.
Figure 4-23. Triple standard concertina fence.
b. Particular. A 300-meter (984 ft.) section of this debate is a platoon task normally requiring less than one hr. There are two operations: conveying and laying out pickets and concertina rolls and installing pickets, and opening and installing concertinas.
c. Get-go performance. For the get-go operation, the piece of work party is divided into three groups of approximately equal size: one to lay out all pickets, one to install all pickets, and ane to lay out all concertina rolls.
(1) The start group lays out front row long pickets at 5 pace intervals on the line of fence (fig. 4-24) with points of pickets on line and pointing toward the enemy. The rear row long pickets are laid out on a line ninety cm (3 ft.) to the rear and opposite the center of interval between the forepart row long pickets. An anchor picket is laid out at each end of each line, 1.five meters (5 ft.) from the terminate long picket.
Figure iv-24. Laying out long pickets for triple concertina fence.
(2) The second group installs pickets starting time with the forepart row (fig. four-25). As in other fences, eyes of screw pickets are to the right. Concave faces of U-shaped pickets are toward the enemy.
Figure 4-25. Installing front row pickets for triple concertina fence.
(iii) The third group lays out concertinas forth the rows of pickets (fig. iv-26). In the front row, ane roll is placed at the third lookout man and one at every quaternary picket thereafter. Sixteen staples accompany each front row concertina. In the 2nd row, 2 rolls are placed at the third lookout man and two at every fourth sentry thereafter. Equally each coil is placed in position, its binding wires are unfastened but are left fastened to the hoop at one end of the curl.
Figure 4-26. Laying out concertina.
d. 2nd operation. Equally they complete the first functioning, all men are organized in four-homo parties (fig. 4-27) to open up and install concertinas, beginning at the caput of the fence. The sequence, shown in general in figure four-27 is as follows:
(1) Open the front row concertinas in front of the double line of pickets and the other two in its rear.
(2) Lift each forepart row concertina in turn and driblet information technology over the long pickets, so join concertina ends every bit shown in effigy 4-28.
(three) Fasten the bottom of the concertina to the ground by driving a staple over each pair of end hoops, one over the lesser of a roll at each long scout, and one at the l/2 and fifty/4 points of the three.8-meter (12.5 ft.) picket spacing. Securing the front concertina to the footing is essential and must be washed earlier installing some other concertina in its rear unless the enemy side of the entanglement is sure to be accessible later.
Figure four-27. Installing concertina.
Figure four-28. Joining concertina.
(4) Stretch a barbed wire strand along the top of each front row and fasten it to the tops of the long pickets, using the top heart tie for screw pickets. These wires are stretched every bit tightly equally possible to improve the resistance of the fence against crushing.
(v) Install the rear row concertina as described above for the front row concertina.
(6) Install the top row concertina (fig. 4-27), fastening the end hoops of fifteen-meter (50 ft.) sections with patently steel wire ties. Brainstorm this row at a point betwixt the ends of the forepart and rear of the lower rows, thus breaking all end joints.
(7) Rack the tiptop concertina to the rear horizontal wire at points halfway between the long pickets. If there is safe access to the enemy side of the argue, similarly rack the meridian concertina to the forrard horizontal wire.
4-11. LOW-WIRE ENTANGLEMENT
a. General. This is a 4- and 2-pace double frock argue in which medium pickets supervene upon long pickets in the debate centerline (fig. four-29). This results in omission of the Nos. 6, 7, and 8 wires, and in bringing all the apron and diagonal wires much closer to the ground and so passage underneath this fence is difficult. This fence may be used advantageously on one or both sides of the double frock fence. The low wire entanglement is used where concealment is essential. In tall grass or shallow water, this entanglement is most invisible and is particularly effective as a surprise obstacle. Notwithstanding, a man tin selection his style through this low wire fence without much difficulty; therefore, for all-time results it must be employed in depth.
Effigy 4-29. Depression wire fence.
b. Structure. Except for the omission of 3 wires and the exchange of the medium pickets, this debate is constructed in the aforementioned mode as the double apron contend.
4-12. High-wire Entanglement
a. Description. This obstacle consists of two parallel 4-strand fences with a tertiary 4-strand fence zigzagged between them to course triangular cells. With 2 rows of pickets equally shown in figure four-thirty, the entanglements is classed as a chugalug; with i or more additional rows of fences and triangular cells it is a band. To add to the obstacle effect, front and rear aprons may be installed and spirals of loose wire may be placed in the triangular cells.
Figure 4-30. Loftier wire entanglement.
b. Structure. A 300-meter (984 ft.) section of loftier entanglement with two rows of pickets, equally shown in figure four-xxx, is a platoon task unremarkably requiring about ii hours, assuming 38 men per platoon. The ii operations are: laying out and installing pickets, and installing wire.
(1) Start operation. For this operation the working party is divided into ii groups, ii-thirds of the men going to the get-go group and one-third to the second. The offset group carries and lays out pickets, front row showtime and at 3-meter (ten ft.) intervals. 2d row pickets are laid out in a line 3 meters (x ft.) to the rear of the front row and spaced midway betwixt them. The first group also lays out an anchor picket in line with each terminate of each 4-strand argue, iii meters (10 ft.) from the nearest long picket. If guys are needed, anchor pickets are also laid out in lines two paces from the lines of the front and rear fences, opposite and midpoint of spaces between the long pickets. The second group installs front row pickets, returns to the caput of the fence, installs the rear row, and so installs the anchor pickets. When the offset group finishes laying out pickets, they begin installing wire and help finish installing the pickets.
(2) Second functioning. Equally the offset task is completed, men motion individually to the head of the fence and are organized into teams of two or four men to install wires in the same way as for the 4-strand fence. The order of installation is as shown in figure 4-thirty, except if forepart guys are used they are installed before the No. 1 wire; rear guys after the No. 12 wire. The lengthwise wires of each iv-strand fence brainstorm and end at an anchor picket.
iv-13. TRESTLE Frock Contend
The trestle frock contend (fig. four-31) has inclined crosspieces spaced at 4.eight- to half dozen-meter (15.seven - 19.vii ft.) intervals to conduct longitudinal wires on the enemy side. The rear ends of the crosspieces are carried on triangular timber frames which are kept from spreading past tension wires on the friendly side. The crosspiece may exist laid flat on the ground for tying the longitudinal wires in identify and and then raised into position on the triangular frames. The frames are tied securely in place and held past the tension wires. The contend should be sited in such a way it tin can be guyed longitudinally to natural anchorages and racked tight.
Figure 4-31. Trestle frock debate.
Figure 4-32. Lapland fence.
4-14. LAPLAND FENCE
Figure four-32 shows the lapland debate which can be used equally well on frozen or rocky ground, and on bogs or marshlands. This fence is wired with six strands of barbed wire on the enemy side, four strands on the friendly side, and four strands on the base. In snowfall, the tripods tin can be lifted out of the snowfall with poles or other ways to reset the obstacle on pinnacle of newly fallen snowfall. On soft ground, the base setting of tripods and the base wires give enough bearing surface to prevent the obstacle from sinking.
4-xv. PORTABLE BARBED WIRE OBSTACLES
Standard concertinas are readily moved and are well adapted for the temporary closing of gaps or lanes, or for calculation rapidly to the obstacle effect of fixed barriers such as the double apron fence. Other portable barbed wire obstacles are described below.
a. Spirals of loose wire. By filling open spaces in and between wire entanglements with spirals of loose wire, the obstacle issue is substantially increased. Spirals for such use are prepared equally follows:
(i) Drive four i-meter (3.3 ft.) posts in the ground to class a diamond 1 by l/2-meter (iii.3 by i.6 ft.).
(2) Air current 75 meters (246 ft.) of barbed wire tightly effectually the frame. Start winding at bottom and wind helically toward meridian.
(iii) Remove wire from frame and necktie at quarter points for carrying or hauling to site where information technology is to exist opened and used. One screw weighs less than nine.1 kg (twenty lbs.) and a homo can behave three or more of them past stepping within the coils and using wire handles of the blazon furnished with the standard concertina.
(iv) If spirals are needed in large quantities, mount the diamond-shaped frame on the winch of a truck and utilise the winch to curlicue the wire.
b. Knife rest. The pocketknife balance (fig. 4-33) is a portable wooden or metal frame strung with barbed wire. It is used wherever a readily removable barrier is needed; for example, at lanes in wire obstacles or at roadblocks. With a metal frame it can be used as an constructive underwater obstacle in beach defenses. Knife rests are normally synthetic with 3 to 4 meters (9.8 to 16.iv ft.) between cross members. They should be approximately 1 meter (iii.3 ft.) high. The cross members must exist firmly lashed to the horizontal member with apparently wire. When placed in position, knife rests must be deeply fixed.
Figure 4-33. Knife rest.
c. Trip wires. Immediately after a defensive position is occupied and before an attempt is fabricated to erect protective wire, trip wires should exist placed simply outside of grenade range, usually 30 to xl meters (98 to 131 ft.). These wires should stretch about 23 centimeters (nine in.) above the ground and be fastened to pickets at not more than than 5-meter (sixteen.iv ft.) intervals. They should be curtained in long grass or crops on a natural line such every bit the side of a path or the border of a field. The Trip wires should be placed in depth in an irregular pattern.
d. Tanglefoot. Tanglefoot (fig. iv-34) is used where concealment is essential and to prevent the enemy from crawling between fences and in front of emplacements. The obstruction should be employed in a minimum depth of 10 meters (32.8 ft.). The pickets should be spaced at irregular intervals of from 75 cm to three meters (2.five to 10 ft.), and the height of the barbed wire should vary between 23 to 75 cm (ix to 30 in.). Tanglefoot should be sited in scrub, if possible, using bushes every bit supports for part of the wire. In open footing, brusque pickets should be used. Growth of grass should exist controlled to aid prevent the enemy from secretly cutting lanes in, or tunneling under, the entanglement.
Figure 4-34. Tanglefoot in barrier arrangement.
4-sixteen. COMBINATION BANDS
As noted in paragraph iv-12, the high wire entanglement may exist congenital with additional rows of fences and triangular cells to form bands of any desired depth or may be made more effective past adding forepart and rear aprons. Other types of fences may exist combined in bands to form obstacles which are more difficult to breach than a single chugalug. Portable spinous wire obstacles may be added as described in paragraph 4-xv. The structure of bands of varied types is desirable because this makes information technology difficult for the enemy to develop standard methods of passage and it permits fitting the obstacles to the situation and to the time and materials available. Six different types of effective combination bands are shown in figure 4-35. Other variations are readily adult.
Effigy four-35. Combination bands of wire obstacles.
Section Iii. Cloth and Labor Estimates
4-17. BASIC CONSIDERATIONS
Barbed wire obstacles are constructed primarily from outcome materials, thus, both logistical and construction estimates are involved. Table 4-ane gives weights, lengths, and other information required for estimating truck transportation and conveying party requirements. Table 4-2 gives the material and labor requirements for construction of various wire entanglements.
4-eighteen. Requirements for a Defensive Position
a. When estimating materials and labor requirements for wire entanglements deployed forth the FEBA, use the following rules of pollex to determine the constructive length of the entanglement:
(1) Tactical wire: Front ten 1.25 x number of belts.
(2) Protective wire: Front x 5 x number of belts.
(3) Supplementary wire:
(a) Forward of FEBA: Front end x 1.25 x number of belts.
(b) Rear of FEBA: Unit depth ten ii.5 x number of belts.
b. When estimating fabric and labor requirements for wire entanglements deployed effectually a perimeter defensive position, use the post-obit rules of thumb to determine the constructive length of the entanglements.
(ane) Tactical wire: Mean perimeter of the wire ten 1.25 x number of belts.
(ii) Protective wire: Mean perimeter of the wire x 1.10 x number of belts.
(3) Supplementary wire: Mean perimeter of the wire x 1.25 x number of belts.
c. Method of estimating. The following step- by-pace procedure is recommended for estimating material, labor, and transportation requirements for diverse lengths and types of wire entanglements.
(1) Make up one's mind the employment by apply, whether Tactical, Protective, or Supplementary wire volition be synthetic.
(2) Determine the depth of employment by totaling the number of belts of wire.
(3) Determine the constructive length of the entanglement by utilizing the appropriate rule of thumb in a or b above.
(four) In order to utilise table 4-iii to determine the quantities of cloth and the manhours required for construction, the effective length must be divided by 300. This gives yous the number of 300 meter sections yous would finer construct. Carry this number out 2 decimal places and then round-off to the nearest 10th.
(a) Multiply the number of 300 meter sections times the values in table 4-three co-ordinate to the type of wire to be constructed. Pay careful attention to the footnotes for this tabular array. You may have more one choice of values and diverse factors may be required to conform the table values.
(b) The number of 300 meter sections is multiplied past the appropriate value in each column of tabular array 4-2, except for the cavalcade entitled Kilograms of materials per linear meter of entanglement. The value in this column is the average weight per meter and should exist multiplied past the full effective length of the entanglement to decide the total weight of the required materials. Divide the full weight by the vehicle chapters to make up one's mind the number of trucks or truckloads required to haul the cloth. Footnote b, to table 4-ii states the vehicle capacity should be 2268 kgs, which equates to 2 l/2 tons. Use of this weight limit volition enable you to brand an accurate estimate of the number of trucks required, whether ii 50/ii ton cargo or 5 ton dump trucks are used. The five-ton dump has less than l/3 the volume capacity of the ii l/ii-ton cargo truck, and the bulk or volume of wire entanglement materials volition limit a 5-ton dump truckload to approximately 2 50/ii tons.
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