By early 1942, it was determined that Oklahoma could be salvaged and that she was a navigational hazard, having rolled into the harbor's navigational channel. Preparations for righting the overturned hull took under eight months to complete. Air was pumped into interior chambers and improvised airlocks built into the ship, forcing 20,000 tonnes (19,684 long tons; 22,046 short tons) of water out of the ship through the torpedo holes. Twenty-one derricks were attached to the upturned hull; each carried high-tensile steel cables that were connected to hydraulic winching machines ashore. On 28 December, Oklahoma was towed into drydock No. 2, at the Pearl Harbor Naval Shipyard. Once in the dock, her main guns, machinery, remaining ammunition, and stores were removed. The severest structural damage on the hull was also repaired to make the ship watertight. US Navy deemed her too old and too heavily damaged to be returned to service. Disaster struck on 17 May, when the ships entered a storm more than 500 miles (800 km) from Hawaii. The tug Hercules put her searchlight on the former battleship, revealing that she had begun listing heavily. had begun to sink straight down, causing water to swamp the sterns of both tugs. As the battleship sank rapidly, the line from Monarch quickly played out, releasing the tug. However, Hercules' cables did not release until the last possible moment, leaving her tossing and pitching above the grave of the sunken Oklahoma. The battleship's exact location is unknown.
