Heading for the East China Sea
After returning to Midway Atoll, the Grayback was quick to set off on her next mission on December 2nd, 1943, for the East China Sea from Pearl Harbor. During this mission, the sub used all of her torpedoes in five days while sinking for Japanese ships in the process.
The Tenth Mission
After returning back from the East China Sea, the Grayback remained in Pearl Harbor for a mere three weeks before setting sail on her tenth and final active service mission on January 28th, 1944. The sub’s last radio contact was February 25th, 1944, which led to the U.S. Navy declaring the vessel lost at sea on March 30th.