US Bomb, 325 lb Depth, AN-Mk 53 Mod 1, Mk 53
The cylindrical welded sheet-stool body has a flat nose. A base closing plate is secured to the rear of the bomb by four bolts. A base closing plate is secured to the rear of the bomb by four bolts.
These bombs are suspended horizontally by two lugs seven inches on each side of the center of gravity, or by a single lug at the center of gravity and 180° removed from the other lugs. There is no external band, the bombs being strengthened internally by a band which is lilted into the bomb at the center of gravity. Trunnions for dive bombing may he threaded to the case and internal strengthening band.
Welded to the tail cone are four vanes which are strengthened by interior box-type struts, and an exterior wide ring strut. The tail cone is secured to the base closing plate by four bolts.
These two bombs (identical except for filling) have been designed to replace depth bombs using athwartship fuzes, since difficulties have been encountered at times in the past with the Athwartship Fuses AN-Mk 224 and AN-Mk 231. The Depth Bombs Mk 53 and Mk 54 will use the Tail Hydrostatic Fuze AN-Mk 230 and a nose fuze, having no athwartship pocket.
The Depth Bombs AN-Mk 53 Mod 1 and AN-Mk 54 Mod 1 differ from the Depth Bombs Mk 53 and Mk 54 respectively in that the suspension lugs are welded on, instead of being of the screw type. In addition, the walls of the explosive cavity of the two bombs are coated with an asphaltic composition known as Hot Melt. The AN-Mk 54 Mod 1 is loaded with HBX rather than Torpex.
Only the modifications of the Depth Bombs Mk 53 and Mk 54 have been standardized as AN bombs.
Collaborative Ordnance Data Repository