## US Naval Mine, Mk 13 Mod 0 Magnetic Induction, Mk 13 Mod 3 Magnetic Induction, Mk 13 Mod 4 Magnetic Induction, Mk 13 Mod 5 Acoustic |

The Aircraft Mine Mk 13 Type is designed as a ground influence mine, laid offensively by aircraft from altitudes of 100 to 500 feet in 10 to 75 feet of water (10-100 feet for Mk 13 Mod 5) against surface craft and up to 500 feet against submarines. The Aircraft Mines Mk 13 Mods 0, 3, and 4 are magnetic induction mines using the Search Coil Firing Mechanism M4, while the Mk 13 Mod 5 is an acoustic mine utilizing the Acoustic Firing Mechanism A3.

When the mine is dropped as a bomb, the minimum altitude of release is 1,200 feet to insure pilot safety. Because of the shape of the mine, the standard bomb nose fuzes require longer air travel to arm.

The body is a cylindrical steel case with a welded hemispherical nose containing a fuze seat liner which houses an adapter ring and two Auxiliary Boosters Mk 1. The cylindrical tail section is of a smaller diameter and is welded to the body. The dome steel tail cover of the Mk 13 Mod 5 is modified to contain the Microphone MI-2; the rubber diaphragm microphone cover of the Mk 13 Mod 5 is stamped with the word “BRUSH.” Horizontal suspension is accomplished by either of three sets of lugs placed 45° apart; each set consists of two standard lugs 11 inches apart.

Black over all.

The extender and clock starter are activated by hydrostatic pressure at a depth of 16 feet or greater. The clock delay runs off in 45 minutes to arm the mine.

The Aircraft Mine Mk 13 Mod 3 is a Mk 13 Mod 0 fitted with the Tail Parachute Pack Mk 1.

In the Mk 13 Mod 4, the extender and clock starter are modified for shallow-water planting, allowing the mine to function in ten feet of water. In other respects the Mk 13 Mod 4 is identical to the Mk 13 Mod 0.

Booster, Auxiliary, Mk 1 Mod 0

Collaborative Ordnance Data Repository

OP 1664, Volume 2 - US Explosive Ordnance (1947)

USNBD - Bombs and Fuzes, Pyrotechnics (1945)