Mk 141 Mod 0

Rocket uses in

Functioning

Arming time

Body diameter, inches

Over-all length, inches

8.5

General: The Nose Fuze Mk 141 Mod 0 is issued to amphibious groups for use in des-troying beach obstacles. The fuze is water-discriminating and so designed that it will not fire on impact with water but will be actuated by impact with the earth or soft sand, provided the water travel before impact is not more than twenty feet. The water-discri-minating feature is obtained by use of a copper shear wire. The Mk 141 Mod 0 will re-place the Mk 152 in the 7.2-inch Demolition Rocket, Head Mk 5.

Description: The fuze was developed from the Bomb Nose Fuze AN-M110A1 and re-tains the upper body and gear-reduction system used in that fuze. To obtain detonator safety, a pivoted detonator shutter has been added below the firing pin. The shutter is held in the safe position by the firing pin, and, when the fuze is armed, the shutter is locked in position by a spring-loaded detent. The safety block of the bomb fuze has been replaced by the arming hub, an integral extension of the stationary gear which located the cross-shaped striker head in the safe position. The movable gear in the Mk 141 Mod 0 acts to thread the striker assembly forward and out of the fuze body, thus with-draw-ing the firing pin from the detonator shutter slideway, releasing the shutter to move into the armed position, and moving the striker head away from the arming hub. The striker and firing pin are mounted, by a copper shear wire, in the inner sleeve which forms the threaded hub of the movable gear. The arming wire bracket of the bomb fuze has been retained and, in shipment, a safety wire ties the vanes to this bracket. To insure proper air flow past the fuze vanes, an elongated booster chamber has been added to the fuze. This cavity, loaded with tetryl increments, extends the tip of the fuze six inches beyond the rocket head. At the lower end of the booster chamber a threaded adapter has been fixed to adapt the 1½-inch diameter fuze to the 2-inch diameter fuze pocket. Two Auxi-liary Boosters Mk 1 Mod 0 are required in the fuze pocket.

Operation: When the rocket is fired, the arming wire is pulled, and the vanes are free to rotate. The rotation of the vanes acts through the reduction gears to thread the in-ner sleeve up in the arming hub and thereby withdrawn the firing pin from the detonator shutter. The shutter is forced across the shutter cavity by its  spring and is locked in the armed position by the spring-loaded detent. On impact, the striker is driven down, shearing the copper shear wire, and fires the detonator, booster lead-in, and booster.

Figure 154. Navy Nose Fuze (Rocket) Mk 141 Mod 0