DATA:

BOMBS USED IN

FUNCTIONING

ARMED CONDITION

FUZES USED WITH

ARMING TIME

Instantaneous

GENERAL:

The Mk 3 Mod 1 is a water impact fuze designed as an integral part of each bomb in which it is used. It consists of a fuze body, mounted in the nose of the bomb, and a vent tube assembly running through the HC filler of the bomb. A washer in front of the fuze body serves to retain the firing pin which is held away from the primer by a creep spring. The primer is mounted over a length of time fuze extends to a quickmatch increament in the starting mixture at the rear of the vent tube. The after end of the vent tube is sealed with a blow-out disc.

The Mk 1 Adapter is attached to the protruding fuze body to insure fuze functioning on either water or land impact. The adapter, which is attached to the protruding body by three set screws, consists of a cup-shaped head mounted on a freely moving plun-ger. The plunger, which is held in its guide by two stop screws, will transmit any blow on the cup to the firing pin. A spring loaded horseshoe collar is mounted beneath the cup to hold the plunger away from the firing pin.

OPERATION:

Upon the relase of the bomb, the arming wire is pulled, releasing the spring loaded horseshoe collar which falls away from the adapter. The fuze is armed. On impact with either land or water, the plunger drives the striker into the primer. The primer ignites the time fuze which burns for 18 seconds and then sets off the quickmatch and start-ing mixture. The starting mixture ignites the HC filler. As pressure builds up in the vent tube, the seal is blown out and since the bomb floats nose down, the smoke passes out the after end of the vent.

REMARKS:

In using smoke bombs for screening landing operations, it was found that a fair num-ber of bombs were dropped on land and the fuze did not function. The addition of the Mk 1 adapter insured functioning of the fuze on either land or water impact.