The V-1302 John Mahn has sat at the bottom of the North Sea off Belgium for decades. The ship began its life in Germany as a 48-meter-long fishing vessel. However, during the Second World War, the Nazi Kriegsmarine requisitioned it for use as a patrol boat. On February 12, 1942, a squadron of six British Royal Air Force planes struck it with two bombs. It sank. It wasn’t just the boat that sank, however. Along with it went its stores of coal and its remaining ammunition, among other chemicals. While the boat’s no longer a Nazi threat, new research suggests...