Japanese Submarine Sinks USS Indianapolis

Context

By late July 1945, American forces held undisputed control of the central and western Pacific, yet scattered Japanese submarines continued to patrol key sea lanes. The Manhattan Project’s urgent need to assemble the first combat atomic weapons required rapid, secure transport of specialized components across vast distances, often aboard fast warships whose movements were shielded by operational secrecy. The USS Indianapolis, a Portland-class heavy cruiser that had seen extensive service since 1932, received orders to carry uranium and other critical parts from the United States to the forward base on Tinian, arriving on July 26.

What Happened

After completing the delivery, the Indianapolis proceeded to Guam and then received orders to sail unescorted to Leyte Gulf in the Philippines to join preparations for the planned invasion of Japan. Just after midnight on July 30, roughly halfway between Guam and Leyte, the Japanese submarine I-58, under Commander Mochitsura Hashimoto, sighted the cruiser on the surface. Hashimoto fired two Type 95 torpedoes; both struck the starboard side, one forward and one amidships. The explosions severed the bow, ruptured fuel and magazine spaces, and knocked out all power. Within minutes the ship took on a severe list and began to settle by the bow. Captain Charles B. McVay III gave the order to abandon ship; the Indianapolis rolled over and sank stern-first approximately twelve minutes after the first torpedo hit, carrying nearly three hundred men down with her.

Aftermath

Roughly nine hundred crew members entered the water with few lifeboats or rafts and almost no food or water. The Navy did not immediately realize the ship was missing because no distress signal had been transmitted and standard movement reports had not been filed. On August 2 a routine patrol aircraft spotted the survivors; rescue operations began that day and continued into August 3, ultimately saving 316 men. The remaining survivors succumbed to exposure, dehydration, and shark attacks over the four days at sea. In November 1945 McVay was court-martialed—the only U.S. Navy captain so charged for the loss of a ship during the war—for failing to zigzag, though Hashimoto testified that zigzagging would not have prevented the attack.

Legacy

The sinking produced the largest single loss of life at sea in U.S. Navy history and prompted postwar reforms in distress signaling, ship-movement reporting, and rescue coordination procedures. McVay’s conviction remained controversial; surviving crew members argued he had been made a scapegoat, and in 2000 Congress passed legislation that effectively exonerated him. The episode continues to illustrate the human cost of maintaining absolute secrecy around strategic operations and the thin margin between routine transit and catastrophe in the final weeks of the Pacific war.