Description
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 gasless 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 supplied 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 Mods 0, 1, and 2 are identical, except that one explosive disc in Mod 1, and two in Mod 2, have been replaced by initial time-delay discs.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.
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, 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 to the first of the explosive capsules. It has the approximate times as follows:
Mod 0 - 30 seconds
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 fuze 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; and Mod 3, 35.
A center connecting rod and end discs support the explosive stack. The secondary delay and parachute ejection charge are located in the 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.
The signal may be ejected from either the hand or the new hydraulic air-operated ejector at any depth.
Functioning
No information about functioning.
See Also
Nothing else to see.
Source(s)
OP 1664, Volume 1 - US Explosive Ordnance (1947)
