American Projectiles and Explosives
Shipboard Pyrotechnics
Submarine Items
Diameter: 3 inches
Delay: 27 seconds
Burning time: 15 seconds
Color: Black, Yellow, Green, or Red
Use: These float signals are used to mark the position of a submerged submarine, and for other marking purposes.
Description: The firing mechanism consists of a firing pin, firing-pin spring, firing-pin lever, and tripping lever or lug. The ignition system consists of a primer, time fuse, quick match, and a starter mixture. The aluminum signal contains a smoke pot, smoke mixture, smoke pot cover, and central tube. The signal has a nose cap and release valve.
Operation: The signal is fired from a submerged submarine, through a tube, using compressed air as a propellant. As the signal is leaving the ejector, a tripping lever is raised by contact with a lug in the gun, cocking and releasing the firing-pin lever, which fires the primer. The primer ignites the time fuse, which burns for 27 seconds. The signal is buoyant and rises to the surface within the 27 seconds of fuse delay. The time fuse ignites a piece of quick match, which, in turn, initiates the starter composition. The starter composition sets off the smoke mixture.
Remarks: The maximum launching depth is 162 feet.
The Submarine Float Signal Mk 2 Mod 0 is similar to the Mk 1 Mod 1, except for a fixed delay of 54 to 59 seconds, a maximum launching depth of 285 feet, and sturdier construction.
Diameter: 3 inches
Burning time: 25 seconds
Delay: 27 seconds
Color of star: Red, Yellow, or Green
Use: These signals are used for submarine emergency identification, whether submerged or surfaced.
Description: The signal consists of a cylindrical aluminum case containing the grenade-type Pyrotechnic Candle Mk 3. The bottom end contains two delay elements. A single-star candle is attached to a parachute by an asbestos cord.
Operation: The shell is projected from the standard submarine emergency identification signal ejector, using compressed air as the propellant. The shell is fired by a lug at its base which projects beyond the side of the shell and rides in a groove in the ejector tube. As the shell is forced through the tube, the extended lug reaches the end of the groove just before the base of the shell passes the muzzle door. The tripping lever is pulled back, thereby cocking and releasing the firing pin lever and firing pin. The firing pin strikes the primer, and the flash from the primer ignites a time fuse. The time fuse burns while the signal is rising to the surface. The delay ignites the grenade-ejection charge, which ejects the signal to a distance of approximately 250 feet. At the summit of the trajectory, the delay train flashes into the signal-ejection charge and causes the parachute-suspended star to be ejected.
Remarks: The Mk 2 Mod 2 is obsolescent, being replaced by the Mk 3 Mods 0 and 1. The Mk 3 Mod 0 has a slightly different method of expelling the inner grenade. The maximum launching depth is 160 feet.
The Mk 3 Mod 1 is similar tot he Mk 2 Mod 1, except for the following:
-A delay of 54 to 59 seconds,
-A maximum launching depth of 285 feet, and
-A sturdier construction to withstand pressures at a lower depth
Pistol Rocket Signal Mk 1, Comet; Mk 3, Shower; and Chameleon
Diameter: 1.5 inches
Burning time: 1 seconds
Intensity: 60,000 candlepower
Color of single star: Red, Yellow, or Green
Use: These signals are used for emergency identification by surfaced submarines.
Description: The upper section or signal chamber contains a pyrotechnic composition and powder-ejection charge. The rocket motor, which is riveted to the signal chamber, contains one gram of black powder above a felt washer and 58 grams of black powder, which is the rocket element. Four spring-loaded hinged vanes, four inches long and one inch wide, are attached to the rocket tube and fold and fit into the rocket chamber. The rocket chamber is an aluminum container with a Primer Mk 5 in its base. This unit receives the rocket motor.
Operation: The signal is fired from the submarine rocket pistol or the Pyrotechnic Pistol AN-M8. Release of the trigger fires the primer, which ignites the one-gram auxiliary propelling charge. This black-powder charge propels the signal chamber and attached rocket motor to about 30 feet from the pistol muzzle. At this point the 58-gram charge of black powder, which is the rocket element, takes effect and propels the signal to a height of approximately 650 feet. The rocket element ignites the expelling charge at the zenith of its trajectory. The expelling charge ignites the star and simultaneously ejects it. The single star falls freely, and burns out just before hitting the water.
Remarks: This signal replaces the chameleon-type submarine rocket signal.
The Rocket Pistol Signal Mk 8 Mod 0 (Shower) is similar to this signal, except that a burst shower is produced instead of a single star.
The Rocket Pistol Signal, Chameleon, is similar to this signal, except that a variety of colors is obtained.
Submarine Emergency Identification Flares Mk 10 Mods 0-2, Mk 11 Mods 0-2, and Mk 12 Mods 0-2
Diameter: 2 inches
Weight: 3.2 pounds
Use: These signals are used by surfaced submarines to identify themselves.
Description: The flare case consists of a seamless steel tube, one end of which is closed by a steel closure disc. The firing mechanism, which extends along the side of the flare body, is attached tot he base casting, which carries the closure disc and primer. The firing mechanism is enclosed in a brass housing which contains the following: (1) a brass shaft held in place by a cotter pin, (2) a firing pin attached to the brass shaft by a sear join, (3) a spring surrounding the firing pin, and (4) a lanyard attached to the brass shaft. The flare case contains the following: (1) a black-powder charge, (2) a starter composition, (3) a pyrotechnic charge, and (4) a steel cup riveted to the case, closing one end. Two clamps are welded to the flare body for mounting on the bracket, fixed to the submarine bridge.
Operation: Mount the flare so that the firing mechanism points toward the deck. A vertical pull on the lanyard forces the brass shaft up, compressing the firing-pin spring. The sear joint between the shaft and firing pin is broken when the shaft is pulled approximately 0.5 inches. The firing pin strikes the primer, which ignites a small charge of black powder. The flash from the black powder ignites the starter composition, which, in turn, ignites the pyrotechnic candle. The flare burns in four increments of 10 seconds duration and intervening blackout increments of five seconds.
Remarks: Flares that have been submerged below periscope depth should be thrown overboard at the first opportunity.
The possibility of detonation in any of the flares, and particularly in those with green pyrotechnics, should never be lost sign of. For this reason, personnel in the vicinity of the flares should be adequately shielded prior to firing.
Submarine Emergency Identification Flares Mk 10 and Mods are similar to the Flares Mk 11 and Mods and Mk 12 and Mods, except that these burn with only one uninterrupted color - Mod 0, red; Mod 1, green; and Mod 2, yellow.
False Target Shell Mk 1 Mod 0
Diameter: 3 inches
Delay: 27 seconds
Persistence of echo: 4 to 18 minutes
Use: This shell is used to confuse and disrupt enemy underwater echo ranging.
Description: The external appearance is similar tot he Submarine Emergency Signal Mk 2 Mod 2. The shell holds six metal cups 2.75 inches in diameter and 1.875 inches in depth, filled with a lithium hydride paraffin mixture. The base of the shell contains a primer, time fuse and 20-gram charge of smokeless powder. Attached tot he base is a firing mechanism which is used with the standard emergency identification signal ejector.
Operation: The shell is projected from the standard emergency identification signal ejector, using 200 pounds per square inch air pressure if possible. The shell is fired by a lug at its base which projects beyond the side of the shell and rides in a groove in the ejection tube. As the shell is forced through the tube, the extended lug reaches the end of the groove just before the base of the shell passes the muzzle door. The tripping lever is pulled back, thereby cocking and releasing the firing pin lever and firing pin. The firing pin strikes the primer, and the flash from the primer ignites a length of time fuse coiled in the base of the shell. The time fuse burns for 27 seconds, and then ignites the 20-gram charge of smokeless powder, which ejects the six cups of lithium hydride. When the lithium hydride touches the water, a chemical reaction occurs which yields fine hydrogen bubbles. The hydrogen bubbles return an echo of the same order and magnitude as that returned by a submarine.
Remarks: False target shells should be segregated from pyrotechnics and other ammunition components, and should be kept in a dry atmosphere.
When visibility is such that surface disturbance may be a hazard, false target shells should not be released from depths less than 150 feet, because small bubbles or a surfaced canister may result.
False Target Can Mk 2 Mod 0
Diameter: 3 inches
Use: False Target Can Mk 2 Mod 0 has the same use as False Target Shell Mk 1 Mod 0.
Description: Generally similar tot he False Target Shell Mk 1 Mod 0, this can is a tube of sheet steel sealed at both ends, containing nine metal cups filled with a lithium hydride composition. These cups can be released individually at any desired rate when used with the new hydraulic-type air-operated signal ejector. The cups are separated by aluminum discs, and a one-inch metal spacer separates the end caps of the outer tube from the top and bottom inner cups. Tear strips are provided at either end to open the can.
Operation: The tear strips, the end caps, the spacers on either end, and the corrugate paper disc at the top end are removed, with the can in a horizontal position to prevent dropping one of the cups. Insert one end into the breech of the ejector about one inch. Put a rammer int he other end of the can and push the cups toward the muzzle of the ejector, until the spring detent near the top of the barrel drops behind the last cup. Remove the empty tube. Place the firing valve on "Vent". Close the breech door and flood the barrel from the sea through the flood line, allowing air to escape through the vent line. When no air escapes the vent or firing valve, close these valves and open the muzzle door.
Make the pressure in the volume tank 50 pounds greater than sea pressure, and through the firing valve into the "Fire" position.
Signal (Pepper) Mk 14 Mods 0-2 (Production Suspended)
No picture available
Diameter: 3 inches
Weight: 19 pounds (approximately)
General: The Signal (Pepper) Mk 14 is an expendable explosive noisemaker for underwater use. It consists of a series of aluminum discs, each of which has sixteen small explosive charges around its periphery. Each disc contains a gas-less fuse train which ignites the charges at one-half second intervals and then communicates the ignition to the succeeding discs. Approximately five minutes of noise can be produced. Parachute suspension is used to retard the sinking rate. A firing device ignites two delay-fuse trains. The initial delay train ignites the first of the explosive discs, and the secondary delay train fires a small black-powder charge which ejects the parachute. The Signal (Pepper) Mk 14 is supplies as Mods 0, 1, and 2, having 30-second, 2-minute, and 6-minute initial delays respectively. Mods 0, 1, and 2 are identical, except that one explosive disc in Mod 1, and two in Mod 2, have been replaced by initial time-delay discs. The effective firing time is the same in all three Mods, for practical consideration.
Tests on the initial production of this device show that about 75% of the units may be expected to operate to completion. It is recommended that, wherever possible, two or more units be fired in quick succession to insure functioning.
Description: The signal consists of the following components: firing device, initial time delay, secondary time delay, a stack of explosive-loaded discs, a center connecting tube and end discs to support the explosive stack, a parachute knock-off charge, parachute assembly, and packing container.
The firing device is identical in operation to the firing device used on the Submarine Emergency Identification Signals. It consists of a support, firing lever, tripping lever, safety pin, and safety cotter pin. When the safety cotter pin is pulled, it allows the safety pin to be forced back by its spring, releasing the tripping lever. On ejection, the tripping lever is forced back by the end of the tripping groove. The tripping lever lifts the firing lever against the firing spring and then releases it to fire the primer. The primer ignites both the initial and the secondary time delays.
The initial time delay is a pyrotechnic fuse train from the primer tot he first of the explosive capsules. It has the approximate times as follows:
-Mod 0: 30 sceonds
-Mod 1: 2 minutes
-Mod 2: 6 minutes
The secondary time delay is a pyrotechnic fuse train from the primer to the parachute knock-off charge. It is approximately five seconds for all three Mods, starting from the time of ejection.
The explosive stack consists of a series of aluminum discs three inches in diameter and one-half inch thick. Each disc has sixteen small explosive-loaded capsules inserted radially around the periphery. The capsules are connected by an internal ring fuse train which is timed to fire the charges at the rate of two shots per second. The number of explosive discs in the stack varies with each Mod as follows:
-Mod 0: 37
-Mod 1: 36
-Mod 2: 35
A center connecting rod and end discs support the explosive stack. The secondary delay and parachute-ejection charge are located int he center tube. The parachute assembly, chute packed in a can which is split open by the ejection charge, is screwed onto the end opposite the firing device.
Ejection: The signal may be ejected from either the hand or the new hydraulic air-operated ejector at any depth.
-Mod 2: 6 minutes
The secondary time delay is a pyrotechnic fuse train from the primer to the parachute knock-off charge. It is approximately five seconds for all three Mods, starting from the time of ejection.
The explosive stack consists of a series of aluminum discs three inches in diameter and one-half inch thick. Each disc has sixteen small explosive-loaded capsules inserted radially around the periphery. The capsules are connected by an internal ring fuse train which is timed to fire the charges at the rate of two shots per second. The number of explosive discs in the stack varies with each Mod as follows:
-Mod 0: 37
-Mod 1: 36
-Mod 2: 35
A center connecting rod and end discs support the explosive stack. The secondary delay and parachute-ejection charge are located int he center tube. The parachute assembly, chute packed in a can which is split open by the ejection charge, is screwed onto the end opposite the firing device.
Ejection: The signal may be ejected from either the hand or the new hydraulic air-operated ejector at any depth.
Next Time: Hand Grenades (Part 1)
