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  3-5-2 AND 10-2-1 DERAILMENT SYSTEMS

  Figure 3.

  III. CRATERING TECHNIQUE.

  A delay cratering technique has been developed that produces excellent results, and it should be considered if time and materials are available. The charges themselves should be either the standard 40-pound cratering charge, or 30 to 40 pounds of C4 (depending to some extent on the depth and diameter of the bore holes). Depth of the holes should be 4 or 5 feet.

  JUNCTION DESTRUCTION

  Figure 4.

  Figure 5.

  Figure 6.

  MANUAL TRACK DISTORTION

  Figure 7.

  The line of two charges above should be primed to be detonated simultaneously. The line of three charges should all be primed to detonate simultaneously after the correct delay. The line of three charges should be detonated from one to two seconds after the first two charges detonate. The delay can be achieved in a variety of ways, but two separate electrical firing systems are probably the easiest. An expedient method of quickly sinking the bore holes themselves is to set up five 15 pound shaped charges (M2A3) over the desired locations. They should be provided with an improvised 30 inch standoff and all be detonated together. The effect of the delay in the cratering operation is to begin to move a large amount of earth around the first two charges, and then before it can fall back into the hole, the second line of charges displaces it entirely. The resulting teardrop shaped crater is very steep sided on the blunt end (the end having the three delay charges).

  IV. IMPROVISED DEVICES.

  Bangalore torpedos, if available, can be extremely effective if employed in an antipersonnel role. Best results are obtained if the Bangalore is planted upright in the ground so that the fragmentation effect will radiate out in 360 degrees.

  TABLE III. CHARGE SIZES.

  Figure 8. Square Charge.

  Figure 9. Cratering Technique.

  The fragmentation hand grenade is a versatile weapon that lends itself to a wide variety of booby trapping actions. One of the simplest booby traps is the grenade-in-a-can. The shipping container or can is affixed to a tree or other permanent object. The grenade, with pull ring removed is placed in the can so that the arming lever is held down by the can. A string or wire is then so placed that the victim will pull the grenade from the can, releasing the lever and detonating the grenade.

  Improvising electrical booby trap firing devices. Each of the following simple booby traps can be used in conjunction with a wide variety of casualty producing charges, from the 3.5 inch rocket, fired by expedient electrical means, to the bangalore torpedo primed to be detonated in an antipersonnel role.

  Open loop. The open loop arrangement shown is the ONLY break in an otherwise complete electrical circuit. A wide variety of actions on the part of the victim could result in pulling the two bare ends of the wire together.

  Expedient firing of 3.5-inch Rocket. The following technique is one method for firing the rocket electrically. Either the cardboard shipping container or a V-shaped wooden trough may be used as an expedient launcher, with the trough being preferred if available. The rocket is prepared for electrical firing by locating the two wire in the nozzle and fin assembly that are coated with clear plastic. (The other green, red, and blue wires are disregarded). After scraping the ends of the clear plastic wires, to provide a good contact for splicing into the firing wire, the connection is made and preferably taped. Experience has indicated that the railing splice is the preferable splice to be used without any adverse effect on rocket accuracy.

  The bare-riding safety band is removed and the rocket is placed on the trough so that the bore-riding safety will face a side of the trough during firing. The shorting clip is removed, the rocket is aimed, an electrical power source is provided and the rocket is fired.

  Obviously results comparable to those obtained by using the launcher should not be expected. As with all expedient demolition work, trial and error experimentation is stressed. An experienced demolitionist can reliably hit a 55 gallon drum, a relatively small target, up to a range of 40 to 50 yards. In an antitank role, satisfactory results could be expected up to 150 yards. The rocket firing can be controlled by the operator, or can be effected by a wide variety of electrical booby trapping techniques. This expedient use of the rocket of course lends itself equally well to employment in an antipersonnel role.

  Figure 10. Open Loop.

  Figure 11. Clothespin.

  Power sources can be a 10-cap blasting machine or any of the following dry cell batteries: BA-317/U, BA-270/U, BA-279/U or combinations of the BA-30/U.

  Safety precautions should include all of those associated with electrical firing as outlined in FM 5-25, Explosives and Demolitions. Although it would be an extremely rare occurrence, we should operate on the assumption that the rocket may blow up on the launching site and take appropriate precautions to prevent injury from such an accident.

  Expedient firing of 3.5 rocket nonelectrically. Remove all wires from fin assembly.

  Remove the plastic cone from fin assembly.

  Place matchheads or other burning material in contact with the ends of the sucks of propellant. Tape matches around end of fuze.

  Place fuze flush against perforated disc, and among matchheads already in the nozzle.

  Remove the hare-riding safety band and place the bore-riding safety pin in depressed position against sides of improvised firing platform.

  V. ADVANCED TECHNIQUES.

  Charges constructed employing advanced techniques generally produce more positive results while using less explosive than required by conventional or standard formulas. Disadvantages of advanced technique charges are that they usually require more time to construct and once constructed they are usually more fragile than conventional charges. Following are rules of thumb for various charges and the targets they are designed to destroy.

  Saddle Charge. This charge can be used to cut mild steel cylindrical targets up to 8 inches in diameter. Dimensions are as follows: The short base of the charge is equal to one-half the circumference. (Note that previously published dimensions called for three times the base, rather than twice the base.) Thickness of the charge is 1/3 block of C3 or C4 for targets up to 6 inches in diameter: use one-half block thickness for targets from 6 to 8 inches in diameter. Above 8 inches in diameter, or for alloy of steel shafts, use the diamond charge. Prime the charge from the apex of the triangle, and the target is cut at a point directly under the short base by cross-fracture. Neither the saddle nor diamond will produce reliable results against non-solid targets, such as gun barrels. These charges benefit from prepackaging or wrapping, providing that no more than one thickness of the wrapping material is between the charge and the target to be cut. Heavy wrapping paper or aluminum foil are excellent, and parachute cloth may be used if nothing else is available. (See figure 14.)

  Figure 12.

  Diamond Charge. This charge can be used to cut hard or alloy steel cylindrical targets of any size that would conceivably be encountered. It has reliably been used, for instance, against a destroyer propeller shaft of 17 inch diameter. Dimensions are as follows: The long axis of the diamond charge should equal the circumference of the target, and the points should just touch on the far side. The short axis is equal to one-half the circumference. Thickness of the charge is 1/3 thickness of a block of C3 or C4. To prime the charge, both points of the short axis must be primed for simultaneous detonation. This can be accomplished electrically or by use of equal lengths of detonating cord, with a cap crimped on the end that is inserted into the charge. As detonation is initiated in each point of the diamond and moves toward the center, the detonating waves meet at the exact center of the charge, are deflected downward, and cut the shaft cleanly at that point. The diamond charge is more time consuming to construct, and requires both more care and more materials to prime. Transferring the charge dimensions to a template or cardboard or even cloth permits relatively easy charge construction (working directly on the targe
t is extremely difficult). The completed wrapped charge is then transferred to the target and taped or tied in place, insuring that maximum close contact is achieved. The template technique should be used for both the saddle and diamond charges.

  Figure 13.

  Ribbon Charge. To out flat or non-cylindrical steel targets the ribbon charges produce excellent results at a considerable savings in explosive. Dimensions are as follows: the thickness of the charge is equal to the thickness of the target to be cut. (Note: never construct a charge less than 1/2 inch thick.) Width of the ribbon is equal to twice the thickness of the target. Length of the charge is equal to the length of the desired cut. Prime from an end; and for relatively thin charges, build up the end to be primed. Build up corners if the charge is designed to cut a target such as an I-beam. Tamping is unnecessary with the ribbon charge. A frame can be constructed out of stiff cardboard or plywood to give rigidity to the charge and to facilitate handling, carrying, and emplacing it. The ribbon charge is effective only against targets up to 2 inches thick, which effectively accounts for the great majority of flat steel targets likely to be encountered.

  Paste Explosive. Excellent results have been obtained in cutting railroad rails and other steel targets by using improvised paste explosive. An example of paste effectiveness follows: the standard steel cutting formula, P = 3/8 A, yields an answer of 560 grams of explosive required to cut a rail 90 lb/yard. Eighty grams of paste explosive were actually used, and this charge removed more than a foot of the track.

  Shaped Charges. If available, manufactured shaped charges will always give results far superior to those produced by any improvised shaped charges. The angle of the cavity of an improvised shaped charge should be between 30 and 60 degrees. Stand-off should be from 1 to 2 times the diameter of the cone. Height of the explosive, measured from the base of the cone should be twice the height of the cone. Exact center priming and tightly packed C4 is important. Trial and error experimentation in determining optimum stand-off is necessary. A point worth mentioning in preparing hollow-bottomed bottles for shaped charge use is to hold the bottle upright when burning the string soaked with gasoline. As the flame goes out submerge the bottle, neck first, in water; and if properly done, the bottle will break cleanly where the string was burned. Hemispherical cavities will produce more surface damage on the target but less penetration. A true cone with an angle of approximately 45 degrees will produce more penetration, which ultimately is the desired results. (See figure 17.)

  Figure 14. Saddle charge.

  Figure 15. Diamond Charge.

  Platter Charge. The platter charge has been developed to breach volatile fuel containers and ignite their contents, from distances up to 50 yards depending on the size of the target. The platter can also employed to destroy small electrical transformers or other similarly “soft” targets, again from a distance.

  Figure 16. Ribbon Charge.

  Platters do not have to be round or conclave although a round, concave platter is undoubtedly best. (The concave side of the platter faces the target, and the explosive goes on the reverse, or convex, side.) First, square or rectangular platters are permissible with steel being the best material. Platter size preferably should be between 2 to 6 pounds, and weight of explosive should approximately equal platter weight. The explosive should be uniformly packed behind the platter and it must be primed from exact rear center. (Build up the C4 in the center of the charge if necessary to insure detonation.) A container is completely unnecessary for the platter charge as long as some way is found to hold the plastic firmly to the platter; tape is acceptable. The range is something in the neighborhood of 25 to 50 yards. With practice, a good demolitionist can hit a 55 gallon drum, a relatively small target, at 25 yards 90 percent of the time. The largest glass or ceramic platters do not give results approaching those of steel.

  Improvised Claymore or Improvised Grapeshot Charge. One of the most effective antipersonnel charge that can be improvised in the field requires the use of C4 and only a few other widely available materials. A container such as a number 10 can is excellent, although virtually any sized can or container could obviously be used. The ratio of projectiles ideally should be small pieces of steel although other objects can be used. Iron, brass, and stones can be used but, for the more fragile items, reduce the weight of explosive and add a few inches of buffer material, either earth or leaves, between the explosive and the projectiles. To prepare the charge, place the projectiles in the container. Next place a layer of thick cloth, felt, cardboard, wood, or some silmilar material over the projectiles. Whenever in doubt about the amount of explosive to use, use a lighter rather than a heavier charge. Again trial and error experimentation is extremely important in arriving at the best charge loading. The effectiveness of the finished product in this case makes all such efforts extremely worthwhile. Pack the C4 uniformly behind the separator disc, prime from exact rear center, and aim the charge toward the center of the desired target area. We obtain excellent results, in dispersion, penetration, and range, by using expended .45 caliber slugs. The main problem to guard against is the tendency to overcharge. A relatively small amount of C4 is all that is necessary to propel the projectiles: anything more will pulverize them.

  Soap Dish. An excellent charge for both rupturing and igniting the contents of volatile fuel containers is the soap dish which, in contrast to the platter charge, must be placed directly on the target. Using a standard GI soap dish, containers up to 100 gallons can be reliably attacked. Charge proportions are as follows: Equal parts by volume of plastic explosive and thermate mix are placed in the container to be used, always insuring that the incendiary mix is placed against the target. The mix can be composed of a number of compounds, among which are: three parts potassium chlorate and two parts sugar, or two parts aluminum powder to three parts of ferric oxide. In lieu of these improvised incendiary mixes, the contents from thermate grenades can be used or military dynamite may be used as the explosive and match heads as the incendiary. As a rule of thumb, a thin cigar box (from an inch and a half to an inch and three-quarters thick) loaded as specified above with one-half C4 to one-half incendiary mix will reliably rupture and ignite volatile fuel containers of up to 1,000 gallon capacity. A charge of approximately twice the size will successfully attack containers of up to 5,000 gallon capacity. To prime the charges always insure that the cap is inserted into the explosive and not the incendiary mix. Holding the charge in place may be accomplished by the use of magnets or adhesive. Always insure that the charge is placed below the fuel level in the container.

  Opposed Charge. (Also called the “counterforce” or “ear muff ” charge.) Within its limitations, which are quite restrictive, the opposed charge offers dramatic savings in explosives for destroying reinforced concrete targets. The rule of thumb for construction is as follows: for each foot of target thickness, up to a maximum of 4 feet, use 1 pound of C4; for fractions of a foot, go to the next higher pound. Divide the total amount of C4 exactly in half, placing one half of the charge on each side of the target, diametrically opposite each other. (This brings up one limitation, the requirement to have two sides of the target accessible.) Prime the two charges to detonate exactly simultaneously, and the target will be destroyed as the shook waves meet in the center of the target and, in effect, cause it to virtually explode from within. It will be noted that the charge size has been reduced by one-half the amount called for in previous publications. This charge is onyl effective and reliable against targets that are approximately square and not much much larger than 4 feet square. (See figure 18.)

  Improvised Cratering Charge. Ammonium nitrate fertilizer is a material that is readily available in many parts of the world. With AN and one other simple ingredient we have the ability to “tailor make” cratering charges to practically any size or configuration. A rule of thumb for the construction of an improvised cratering charge is as follows: to each 25 pounds of ammonium nitrate fertilizer, which should be the prilled or pelleted variety,
add approximately 1 quart of diesel fuel, motor oil, or gasoline. The motor oil may be drained from a crankcase, which will not impair the effectiveness of the charge. Allow the charge to soak for 1 hour, prime with 1 pound of TNT, or its equivalent, tamp well in an appropriate bore hole, and detonate. The results obtainable with this charge compare very favorably with the manufactured variety. The prilled Ammonium Nitrate fertilizer should be of a kind having at least 33 1/3 percent nitrogen content and care should be exercised to see that the fertilizer used is not damp. Obviously it cannot be left for extended times in a borehole or water will reduce the effectiveness of the charge. When difficulty is encountered in producing a borehole diameter that is capable of accommodating the bulk of the manufactured 40 pound cratering charge, 8 1/4 by 17 inches, excellent results can be obtained by pouring and tamping the improvised AN cratering charge into the available space.