Used in: 4.5-inch Rocket Head Mk 3 (High Capacity)

Overall dimensions and weight of fuze:

Length

Diameter (maximum)

Body threads

Weight

Applicable specification: (to be prepared)

General arrangement drawing:

344601 (Mod 0)

422548 (Mod 1)

Sketch list of drawnings & specs:

102957 (Mod 0)

109583 (Mod 1)

Explosive components:

Delay assembly consisting of a Detonator Mk 31 and a Primer Mk 105. Delay is 0.02 second.

Booster lead-in housed in the magazine.

Booster charge (approximately 11.5 grams of tetryl) housed in the magazine.

General. Nose Fuzes Mk 145 Mods 0 and 1 are rocket fuzes designed principally for rockets launched from small craft to provide a beach barrage prior to landing operations. The fuzes are air arming and impact firing and are similar to the Mk 137, but incorporate a 0.02 second delay in the detonator assembly.

Figure 13 – Nose Fuze Mk 145, External View, Full Size (approximately)

Use. Fuze Mk 145 is used in the 4.5-inch High Capacity Fin Stabilized Surface Rocket (Complete Round) Mk 1 Mod 0. (See OP 1415). This fuze is used when a delay detonation on impact is desired.

Functioning mechanism. The functioning mechanism of Fuze Mk 145 is similar to the mechanism of Fuze Mk 137. The differences incorporated in the mechanism of Fuze Mk 145 are:

1. The arming shaft which mount the propeller is attached to the firing pin by means of a locking pin. The purpose of the locking pin (which may be sheared upon impact) is to prevent the firing pin from being forced too deeply into the shutter thus disrupting the delay element on heavy impact.

2. The fuze contains a delay element which is initiated by a firing pin with a rounded point.

3. The magazine is designed to receive the booster lead-in which climinates a separa-te lead-in disc.

Differences in mods. The Fuze Mk 145 Mod 0 is similar to the Fuze Mk 137 Mod 1 but has a 0.02 second delay. The Fuze Mk 145 Mod 1 is similar to Fuze Mk 137 Mod 2 with a 0.02 second delay.

Figure 14 – Nose Fuze Mk 145 Mod 1, Cross Section View,
Armed and Unarmed Position

Arming. Arming of the Fuze Mk 145 is identical with Fuze Mk 137.

Firing. Similar to firing of Fuze Mk 137, but fuze functions with a 0.02 second delay after impact.

See Fuze Mk 137.

See Fuze Mk 137.

See Fuze Mk 137.

See Fuze Mk 137.