The USS Oglala (CM-4) capsized at Pearl Harbor, USS Helena (CL-50) is on the left.
The USS Oglala (CM-4) was a minelayer ship in Pearl Harbor when the Japanese attacked December 7, 1941. While the Oglala did not take any direct hits, a nearby bomb and torpedo explosions from the Japanese caused significant underwater damage. About two hours after receiving her initial damage, the USS Oglala rolled over and sank. According to the book, Rendezvous At Midway (New York: The John Day Company), wags in the Navy said that “she had died of fright.”
The USS Oglala was originally evaluated as a total loss. The only salvage goal was to clear the ship from the pier for valuable space. However, it was ultimately decided to fully recover and repair the ship, and the USS Oglala became the subject of a big salvage effort.
The USS Oglala in the summer of 1941.
USS Oglala Specs
- Type: Minelayer
- Displacement: 3,746 long tons (3,806 t)
- Length: 386 ft 7 in (117.83 m)
- Beam: 52 ft 2 in (15.90 m)
- Draft: 14 ft 7 in (4.45 m)
- Propulsion: Triple Expansion Machinery, Twin Screws, 7,000 hp (5,220 kW)
- Speed: 20 knots (37 km/h; 23 mph)
- Range: 5,000 nmi (9,300 km)
- Capacity: 110 men
- Complement: 200
- Armament: 300 mines
- Aircraft carried: 6
USS Oglala Salvage
The salvage effort for the USS Oglala was complex. Think about righting and refloating a capsized ship with poor stability. Not an easy task.
Divers spent nearly 2,000 hours underwater on the salvage effort. Reports say there was between 15 to 18 divers, and that’s about 133 hours for each diver to be underwater. Have you ever spent an hour underwater? That’s a long time to be in the Harbor.
These divers spent their time patching the hull, rigging chains, cutting away unwanted structure and executing many other tasks. After her top hamper had been removed, ten salvage pontoons were used to pull the ship upright while air was pumped into her to lighten the load. The first attempt to right the Oglala failed after several connecting chains parted. However, the USS Oglala was righted after a second try twelve days later.
Still, even though the Oglala was upright, the ship was still mostly underwater. The salvage effort was not yet complete.
A large wooden cofferdam was built around the edges of her decks to allow water to be removed from her interior. The ship was refloated in June, but resank after a pump failure led to cascading flooding in her forward hull. The Oglala was brought afloat again a few days later, and promptly sank again for a third time after the cofferdam failed.
No one said this was going to be easy, and it wasn’t over yet! A few days later the Oglala was raised again, and a serious fire nearly produced a fourth resubmergence!
However, the next day Oglala was finally drydocked, completing a legendary salvage effort. The USS Oglala continued to receive temporary repairs during much of the rest of 1942 and, in December, left Pearl Harbor for the U.S. west coast, there to be refurbished for active service.
USS Oglala after refloating, 1942.
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