Sumner supports Ehime Maru lift

Story courtesy of American Maritime Officers

Chief Mate Charles Reina, Bosun Art Cros and Able Seaman Colins Agyemang prepare the apparatus USNS Sumner used to track currents during the tansfer of Ehime Maru to the shallow-water recovery site. Dub Allen photos

Military Sealift Command's USNS Sumner filled a crucial role in the multi-month recovery and relocation of Japanese fisheries training vessel Ehime Maru near Honolulu, Hawaii.

Ehime Maru sank Feb. 9, 2001, when U.S. Navy submarine USS Greeneville collided with her about nine miles south of Oahu. Greene-ville was demonstrating an emergency surfacing maneuver during routine operations when her stern gashed the hull of the 190-foot training vessel. Nine people aboard Ehime Maru — two teachers, four 17-year-old students and three crewmembers — died, and 26 people were rescued.

After the accident, the Navy pledged to attempt to recover the bodies of the deceased. To do so, salvage engineers moved the 830-ton Ehime Maru from her initial resting place in 2,003 feet of water to a shallow site, located about one mile south of Honolulu International Airport in about 115 feet of water.

Sumner, an oceanographic survey ship, conducted a detailed survey of the 14-mile route over which the Ehime Maru would be transported to the shallow water recovery site.

Sumner also deployed current meters and buoys, collected ocean sediment samples and took conductivity, temperature and depth measurements prior to the operation.

During the transfer of Ehime Maru, Sumner maintained a distance of 0.25 nautical miles from Rockwater Two, a privately owned, multipurpose diving vessel used to lift the training vessel from the bottom of the ocean and move it to the shallow water recovery site. During the transfer, Sumner monitored currents using an Acoustic Doppler Profiler Transducer, which measures currents from the surface of the water to the ocean floor, and provided real-time data on the currents in front of Rockwater Two.

"This involved precise navigation and tracking within a few meters of the assigned path at speeds of approximately 0.8 knots," said Capt. Fred Smallwood, master of Sumner during the operation. "There were frequent stops along the way for the Ehime Maru to be raised as the depth of water decreased."

USNS Sumner (far left) monitored currents while Rockwater Two lifted and relocated Japanese fishing vessel Ehime Maru. The Japanese vessel sank Feb. 9, 2001, when a U.S. Navy submarine collided with her.

The Navy located the wreck of Ehime Maru Feb. 16, 2001. The Navy's remotely operated vehicle Scorpio II detected the Japanese vessel using its on-board sonar. Positive identification was made four minutes after discovery by using Scorpio II's video cameras to read the stern plate of the vessel, which was found sitting nearly upright on the ocean floor.

Sumner began work on the relocation of the Japanese vessel in June 2001. From June 17 to 22, Sumner conducted a bathymetry survey from the deep-water location of Ehime Maru to the shallow-water recovery site, measuring the depth of the ocean along the route that would be used to move the vessel. Sumner also took conductivity, temperature and depth measurements and deployed current meter arrays on both sites.

Later in the month, Sumner made repeated passes over the transit route to ensure accurate, detailed coverage of the ocean floor. From July 17 to 20, the current meter arrays were retrieved, and Sumner collected additional conductivity, temperature and depth measurements. In August, Sumner tested the Acoustic Doppler Profiler Transducer and made preparations to participate in the transfer of Ehime Maru.

Rockwater Two began efforts in August to lift and position Ehime Maru for transport. She successfully moved the Ehime Maru Oct. 5, positioning it on a level area of the ocean floor. The salvage crew positioned lifting plates under the pilot house and engine room and assembled a frame around the vessel over several days.

Rockwater Two began lifting Ehime Maru Oct. 12 at 1:30 a.m. They raised the vessel approximately 100 feet from the ocean floor and towed Ehime Maru beneath the water. Rockwater Two set Ehime Maru down in the shallow water recovery site at 3:22 p.m., Oct. 14.

The salvage team recovered eight of the nine victims of the Feb. 9 collision from the wreck. The cost of the project has surpassed $60 million.

Sumner was released from duty on the evening of Oct. 13 as she reached the shallow water recovery site. The officers and crew received a "thanks for a job well done" from Capt. Bert Marsh, USN, the supervisor of diving and salvage from the Naval Sea Systems Command.