氷川丸
The Japanese naval base at Truk was a large, sprawling complex, with hundreds of vessels anchored among dozens of islands, surrounded by a protective coral reef. The islands were studded with airfields, hospitals, repair shops, storage sheds, fuel depots, and command facilities. It was defended by coastal guns in concrete casemates, hundreds of fighter planes, and hundreds of anti-aircraft guns of all types, both on ship and shore. "Heian Maru" was moored next to her sister ship "Hikawa Maru" (in wartime service as a hospital ship) on the leeward side of Dublon Island when, on the morning of 17 February 1944, the Americans launched Operation Hailstone.