Type A Depth Charge (UK)
The British Type A Depth Charge was an early, small antisubmarine weapon adapted from the "Vernon boom" described in the Annual Report of the Torpedo School, 1915.
The total weight of the weapon was 210 pounds, only about 1⁄7th of this weight being explosive: 32.5 pounds of gun cotton initiated by a G.C. primer of 2.25 pounds.
Explosion was triggered mechanically by a float and wire system at a depth of 40 feet. Vernon calculated that this gave the weapon a 10 foot danger radius. It was the first British depth charge to be used and was in general use by small craft in October 1915.
The Type B was a minor refinement of the design, offering an 80 foot detonation depth option and a lower overall weight, and the Type E greatly increased the proportion of explosive comprising the overall weight.
- Annual Report of the Torpedo School, 1915. Plate 82.
- Annual Report of the Torpedo School, 1915. pp. 164-5, 172, Plate 73, Plate 82.