The Japanese attack on Pearl Harbor was planned as the initial step of their Pacific campaign. Admiral Isoruku, then Commander-in-Chief, Combined Fleet, supposedly originated the plan in early-1941.
The force assembled 2 battleships, 6 carriers, 3 cruisers, approximately 20 destroyers and 5 submarines, including midgets which were carried by mother submarines.
The force departed at 6 am, November 26, Japan time, and set an indirect northern course for the next rendezvous, 200 miles north of Oahu. On December 6, when the force was still 800 miles north of O‘ahu; it received the long awaited code message to proceed with the attack.
When the Japanese attacked, 86 vessels, including 8 battleships, 7 cruisers, 28 destroyers and 5 submarines, plus the usual complement of small craft, were based in the harbor (there were no aircraft carriers moored at Pearl Harbor at the time.)
When the onslaught subsided, nearly every ship bore scars. One of the worst damaged, the Oklahoma, was salvaged by one of the most complex operations in history. (Morris) Salvage efforts concentrated on the least damaged ships first, the Oklahoma was one of the last ships to receive serious attention.
The Oklahoma was, at the time of the attack, located outboard of the battleship Maryland, which was moored alongside Ford Island. She was struck on the port side by four to nine torpedoes, which caused the ship to capsize quickly and come to rest on the bottom at an angle of over 150-degrees from upright.
The righting and refloating of the capsized battleship Oklahoma was the largest of the Pearl Harbor salvage jobs, and the most difficult. Because the Oklahoma was old and very badly damaged, future active service was not seriously contemplated. The salvage effort focused on clearing an important mooring berth for further use.
Refloating operations were commenced by installing four independent patches in breaches of the hull, the largest of which consisted of five sections and was 130 ft long by 57 ft high.
The external structure served to reinforce the patch, which consisted of 4-in. thick siding sealed with packing materials. The sections were secured to the sides by means of hook bolts installed in holes burned by divers through the damaged shell of the ship. The patches were sealed by means of concrete poured into forms along the bottom and up both ends.
Fuel oil, ammunition and some machinery were removed to lighten the ship. Coral fill was placed alongside her bow to ensure that the ship would roll, and not slide, when pulling began.
Oklahoma’s port side had been largely torn open by Japanese torpedoes, and a series of patches had to be installed. Divers worked in and around her to make the hull as airtight as possible; their work was critical to the salvage success.
They wore deep-sea diving dresses weighing 185-lbs, and worked for many hours several hundred feet from access openings. All of this was done in total darkness, underwater lamps being of no use because of the excessively murky water.
All in all, about 6000-individual dives were made, during salvage operations at Pearl Harbor, averaging approximately four hours per dive.
An extensive system of righting frames (or “bents”) and cable anchors was installed on the ship’s hull, twenty-one large winches (the winches were powered by motors from Honolulu street cars) were firmly mounted on nearby Ford Island, and cables were rigged between ship and shore. (Navy)
The Oklahoma capsized in a position parallel to the shore. Righting operations involved the use of 21 five hp DC motor-driven winches, each of which, through two 17-part tackles, applied an approximately horizontal force transverse to the ship.
To allow turning moments, pendants extending from the outer blocks were secured to the tips of 21 40-ft-high “A” frames mounted on the above-water portion of the starboard bilge.
The first pull began on March 8, 1943, the final pull was on May 20, 1943 – it took 74-days to turn the ship over. She was floated by pumping air into air-tight compartments and pumping water out of the hull.
The ship came afloat in early November 1943, and was drydocked in late December. Once in Ship Yard hands, Oklahoma’s most severe structural damage was repaired sufficiently to make her watertight.
Guns, some machinery, and the remaining ammunition and stores were taken off. After several months in Drydock Number Two, the ship was again refloated and moored elsewhere in Pearl Harbor
The Oklahoma was later sold to the Moore Drydock Co of Oakland, California, for scrapping. On May 17, 1947, while under tow, the Oklahoma sank 540-miles out of Pearl Harbor with no one on board.
In the attack on Pearl Harbor, there were 2,402 US deaths from the attack. 1,177 of those deaths were from the USS Arizona, while 429 of the deaths were from the USS Oklahoma (14 Marines and 415 Sailors.)
Thirty-five crew members were positively identified and buried in the years immediately after the attack. By 1950, all unidentified remains were laid to rest as unknowns at the National Memorial Cemetery of the Pacific.
Recently, the Defense Department recovered for identification and return to families the last of 388 sailors and Marines killed on the battleship USS Oklahoma on December 7, 1941, and later buried as “unknowns” in the National Memorial Cemetery of the Pacific at Punchbowl. (Lots of information here is from Navy, Morris and USSOklahoma-com.)