bantarleton:

This illustration, from ACM 21: Battle of the Atlantic 1942–45 by Edouard A Groult, shows the loss of K-74 in July 1943. Having spotted a U-boat on radar, K-74 made visual contact with U-134 running surfaced, heading in the direction of a nearby tanker and freighter. To protect these ships, K-74’s commander, Lieutenant Nelson G. Grills, chose to attack U-134. The encounter ended badly for K-74. Attacking just before midnight on 18 July 1943, K-74 opened fire with its .50-calibre machine gun at 250 yards. Passing directly overhead, the bombardier dropped two depth charges – which failed to sink the U-boat. A second pass would be necessary. Meanwhile, U-134’s anti-aircraft battery returned K-74’s fire, and with a target larger than U-134, successfully hit it. The blimp’s starboard engine was knocked out and the cells holding the blimp’s helium were repeatedly punctured.