The USS Megrez was a Crater-class cargo ship in the service of the US Navy during World War II. The ship was built under a MARCO contract as the Liberty Ship SS General Vallejo, by California Shipbuilding Corporation, in March 1943. Once it was acquired by the Navy, the ship was converted and sent to Micronesia. The ship operated out of Funafuti and Kwajalein until mid-1944, distributing supplies to mobile supply base craft. In June and August 1944, the ship provided support for the invading forces on Saipan and Tinian and then sailed for Eniwetok, where it remained for 7 months, serving as a floating supply and freight depot, providing lube oil to the warships as they advanced towards the enemy’s home islands. Towards the end of the war, the USS Megrez provided support for the Philippines operations before returning to Pearl Harbor to be placed out of commission. It was laid up in the reserve fleet at Suisun Bay and remained there until it was bought by Zidell Exploration, Inc. for non-transportation use.