OP 1664 - U.S. Explosive Ordnance (Vol. 2); Part 6 - Bombs and Bomb Fuzes; Chapter 20 - Bomb Fuzes; Section 3 - Navy-Designed Bomb Fuzes: Mk 232 Mod 1 (Nose Impact or Electrical Firing)

U.S. EXPLOSIVE ORDNANCE

PART 6 - BOMBS AND BOMB FUZES

Chapter 20 - BOMB FUZES

Section 3 - NAVY-DESIGNED BOMB FUZES

Mk 232 Mod 1 (Nose Impact or Electrical Firing)

Bombs	All G.P. and depth bombs, and old-tpye demolition and L.C. bombs
Functioning	Impact instantaneous or electrical impulse
Armed condition	When vanes are 3/8 inch away from striker housing
Fuzes used with	Usually none
Arming time	8 vane revolutions
Over-all length, inches	7
Body diameter, inches	2.5
Vane span, inches	5.125 (6 vanes)
Material	Steel and brass

General: The Nose Impact or Electrical Firing Fuze Mk 232 Mod 1 is a bomb nose fuze of the arming-vane type, requiring little air travel to arm. It may be initiated by an elec-trical impulse or impact on a hard surface, detonating instantaneously. The fuze has an electric semi-cap which, when fired by an impulse, blows through a hole leading to the detonator and sets it off. For electrical firing as well as impact, the fuze must first be armed, allowing the detonator slider to move over into a position where the detonator can be initiated by either the firing pin or the explosion of the semi-cap.

Operation

As an impact fuze: A cotter oin, which is wired in place with a small fuze wire, pre-vents the arming vanes from rotating. The arming wire is attached to this cotter pin, and withdrawal of the arming wire breaks the light fuze wire. The vanes are then rotated by action of the wind stream, and this rotation is transmitted to the striker, which advances on the threads in the striker housing. It advances until stooped by the striker stop com-ing up against the bottom of the striker housing. As the striker advances on its threads, it withdraws the firing pin from the slider, which is then forced over by its springs, lining the detonator up with the firing pin and booster lead-in. A detent locks the detonator slider in the armed position. Upon impact, the brass collar threads are sheared by the firing-pin block, and the firing pin is forced into the detonator.

Electrical firing: Detonation is initiated by means of the squip being directly fired by an electric current through the igniter bridge.

Remarks: The fuze will not function on impact with water, but must strike a hard sur-face in order to strip the striker housing threads.

No attempt should be made to unarm this fuze by rotating the vanes backward.

Figure 369. Nose Impact or Electrical Firing Fuze Mk 232 Mod 1