USNBD, Bombs and Fuzes; Section I - High Explosvie Bombs; Part III - U.S. Army-Navy "AN" Series Bombs: 1000 lb. Mk 13

U.S.N.B.D. - UNITED STATES - BOMBS AND FUZES; PYROTECHNICS

SECTION I - HIGH EXPLOSIVE BOMBS

PART IV - U.S. ARMY-NAVY "AN" SERIES BOMBS

DATA:		U.S. NAVY MINE
		1000 LB. AIRCRAFT MINE
OVERALL LENGTH	68.75 in.
DIAMETER
Case	19.875 in.
Tail section	15.25 in.	Ground Influence Fired
Fins on tail section	25.50 in.	Mk 13 Mod 0 Magnetic Induction
		Mk 13 Mod 3 Magnetic Induction
		Mk 13 Mod 4 Magnetic Induction
		Mk 13 Mod 5 Accoustic
		(Service)

WEIGHTS:

	Mk 13 Mod 0, 3, 4		Mk 13 Mod 5
Type of Filling	T.N.T.	Torpex	T.N.T.	Torpex
Weight of Filling	640 lbs.	700 lbs.	640 lbs.	700 lbs.
Total Weight	1030 lbs.	1090 lbs.	1000 lbs.	1060 lbs.
Chg/Wt. Ratio	62.0%	63.3%	64.0%	66.0%
Negative Bouyancy	430 lbs.	490 lbs.

FUZING:

For use as Mine:	Athwartship - Mine Mechanisms
Forward well:	Extender and Booster
After well:	Clock Starter and Clock Delay
For use as Bomb:
Nose:	AN-M103, AN-M103A1, M135, M135A1, M136, M136A1, M139, AN-M139A1, M140, AN-M140A1, M149, M163, M164, M165, AN-Mk 219 (by using adapter ring and one Mk I aux. booster).

GENERAL:

The Mk 13 is designed as a ground influence mine, laid offensively by aircraft from altitude of 100 to 500 feet in 16 to 75 ft. of water (40-100 ft. for Mk 15-5) against surface craft and up to 500 ft. against submarines.

The Mk 13-0-3-4 are magnetic induction mines using the M-4 Search Coil firing mechanism, while the Mk 13-5 is an acoustic mine utilizing the A-3 acoustic firing mechanism.

When dropped as a bomb, the minimum altitude of release for the mine is 1200 ft. to ensure pilot safety. Because of the shape of the mine, the standard bomb nose fuzes require longer air travel to arm.

MINE CONSTRUCTION:

The body is a cylindrical steel case with a welded hemispherical nose containing a fuze seat liner which houses an adapter ring and two Mk I auxiliary boosters. The cylindrical tail section is of a smaller diameter and is welded to the body. The dome steel tail cover of the Mk 13-5 is modified to contain the MT-2 microphone; the rubber diaphragm microphone cover of the Mk 13-5 is stamped with the word "BRUSH". Horizontal suspension is accomplished by either of three sets of lugs plac-ed 45° apart; each set consists of two standard lugs 14 in. apart.

COLOR & MARKINGS:

Black overall.

REMARKS:

The Extender and Clock Starter are functioned by hydrostatic pressure at a depth of 15 ft. or greater. The Clock Delay runs off in 45 minutes to arm the mine.

The Mk 13-3 is a Mk 13-0 fitted with the Tail Parachute Pack Mk 1.

In the Mk 13-4, the Extender and Clock Starter are modified for shallow water planting, allowing the mine to function in 10 ft. of water. In other respects the Mk 13-4 is identical to the Mk 13-0.