Ehime Maru and USS Greeneville collision

On 9 February 2001, about nine nautical miles (17 km; 10 mi) south of Oahu, Hawaii, in the Pacific Ocean, the United States Navy (USN) Los Angeles-class submarine USS Greeneville (SSN-772) collided with the Japanese fishery high-school training ship Ehime Maru (えひめ丸) from Ehime Prefecture. In a demonstration for some VIP civilian visitors, Greeneville performed an emergency ballast blow surfacing maneuver. As the submarine shot to the surface, she struck Ehime Maru. Within ten minutes of the collision, Ehime Maru sank. Nine of the thirty-five people aboard were killed: four high school students, two teachers, and three crew members.

Many Japanese people, including government officials, were concerned by news that civilians were present in Greeneville's control room at the time of the accident. Some expressed anger because of a perception that the submarine did not try to assist Ehime Maru's survivors and that the submarine's captain, Commander Scott Waddle, did not apologize immediately afterwards. The USN conducted a public court of inquiry, blamed Waddle and other members of Greeneville's crew, and dealt non-judicial punishment or administrative disciplinary action to the captain and some crew members. After Waddle had been questioned by the Naval Board of Inquiry, it was decided that a full court-martial would be unnecessary, and he was forced to retire and given an honorable discharge.

In response to requests from the families of Ehime Maru's victims and the government of Japan, the USN raised Ehime Maru from the ocean floor during October 2001 and moved it to shallow water closer to Oahu. Once there, USN and Japanese divers located and retrieved the remains of eight of the nine victims from the wreck. Ehime Maru was then moved back out to sea and scuttled in deep water. The USN compensated the government of Ehime Prefecture, Ehime Maru's survivors, and victims' family members for the accident. Waddle traveled to Japan in December 2002 to apologize to the ship's survivors and victims' families.

The accident renewed calls by many in Japan for the United States to make more effort to reduce crimes and accidents involving U.S. military personnel who injure or kill Japanese citizens. In response to the accident, the USN changed its policies regarding civilian visits to its ships.

Incident

Prelude

On 10 January 2001, Ehime Maru, a Japanese fishing trawler owned by the government of Ehime Prefecture, 191 feet (58 m) in length and measuring 741 gross tons, departed from Uwajima Fisheries High School, a high school in Uwajima, Ehime Prefecture. The ship, captained by Hisao Ōnishi, headed for Hawaii on a planned 74-day voyage to train high school students who were interested in pursuing careers as fishermen. A total of 35 people were on board Ehime Maru: 20 crewmembers, 13 students, and two teachers. The ship's curriculum included long-line tuna fishing, maritime navigation, marine engineering, and oceanography. The ship docked at Honolulu Harbor on 8 February.

On 9 February, USS Greeneville, a U.S. Navy nuclear-powered attack submarine, prepared to depart Pearl Harbor, Hawaii, to perform a public relations mission as part of the USN's Distinguished Visitor Embarkation (DVE) program. The program took civilians, members of Congress, journalists, and other "opinion makers" for rides on nuclear submarines to demonstrate the submarines' capabilities; its goal was to demonstrate the need to maintain a fleet of nuclear-powered submarines. Greeneville had previously participated in several DVE missions, carrying notable civilians such as Tipper Gore and James Cameron. For this mission, Greeneville was to carry 16 civilian Distinguished Visitors (DVs): eight corporate chief executive officers (CEOs), six of them with their spouses; and a free-lance sports writer with his spouse. The CEOs were in Hawaii to assist a fundraising effort to restore the retired battleship Missouri. This DVE visit had originally been arranged by retired Rear Admiral Richard C. Macke who was a former commander of the Pacific region before his early retirement in 1996 and volunteered for the Missouri Memorial Association. Accompanying the DV civilians on the mission was Navy Captain Robert L. Brandhuber, Chief of Staff for Rear Admiral Albert H. Konetzni Jr., the commander of the submarine component of the United States Pacific Fleet, abbreviated as COMSUBPAC. The captain of the Greeneville, Commander Scott Waddle, had commanded the submarine during several previous DVE missions.

Before departing for the mission, Commander Waddle was informed that the ship's Analog Video Signal Display Unit (AVSDU) was inoperative. The AVSDU was an analog video monitor, located forward of the submarine's periscope in the control room, that displayed information from the submarine's three sonar stacks and screens. The monitor helped communicate sonar information to the officer of the deck. Waddle decided to continue with the mission without attempting to repair the monitor, believing that it was not a crucial piece of equipment.

Greeneville departed Pearl Harbor on time at 08:00 local time (HST) with a crew of 106 in addition to the 16 DV passengers and Chief of Staff Brandhuber. As the submarine transited the ship channel from Pearl Harbor, Waddle noticed that the weather was "hazier than normal", but he thought that the haze would burn off soon. Greeneville reached its dive point south of Oahu (21°6′N 157°55′W) slightly later than scheduled, at 10:17, and submerged. The DVs were scheduled to be served lunch in two sittings, the first from 10:30 to 11:30 and the second from 11:30 to 12:30. After lunch, the submarine was to display its operational abilities and then return the DVs to Pearl Harbor for a reception that was scheduled to begin at 14:30. The lunch service ran late, and other Greeneville officers repeatedly reminded Waddle that the submarine needed to begin its demonstration maneuvers or it would be late back to port. Finally, at 13:10, Waddle entered the submarine's control room and prepared to execute the demonstration. Fifteen of the 16 DVs and Brandhuber entered the control room to observe the maneuvers.

Meanwhile, at 12:00, Ehime Maru had departed Honolulu harbor en route to fishing grounds about 300 nautical miles (560 km) south (14°N 156°W) of Oahu. By 12:50, the ship was proceeding at 11 knots (13 mph; 20 km/h) about eight nautical miles (15 km) south of Oahu and was nearing the area where Greeneville was conducting the DVE cruise.

Three crewmen were on duty in Greeneville's sonar room. At 12:30, the submarine's sonar operators detected a surface vessel in the vicinity and designated the contact as "Sierra 12" (S-12). A few minutes later, they detected a second vessel estimated to be about 20 nautical miles (37 km) away, which was designated as "Sierra 13" (S-13). S-13 was Ehime Maru. Also tracking the sonar contacts in the control room was Patrick Seacrest, Greeneville's sole fire control technician on duty at the time. Seacrest was responsible for "determining the course, speed, and range of surface and submerged vessels (or targets) potentially posing a threat to the submarine." At 12:58, Seacrest designated the track of S-13 as heading away from Greeneville's location. Beginning at 13:00, Seacrest elected to discontinue updating the Contact Evaluation Plot (CEP) in the control room. The CEP is a "labor-intensive" paper display that plots ship data and contact information for reference by control room personnel. Seacrest stated that one of the reasons that he decided to stop updating the CEP was that the DV guests were standing between his watchstation and the CEP.

Collision

Before beginning the maneuvers, Waddle checked the submarine's sonar contacts and noted that there were several surface vessels in the vicinity, but none closer than seven nautical miles (13 km) away. Ehime Maru was one of these vessels. The civilians were spread throughout the control room, with three on the periscope platform and others in front of the fire control station, restricting free access to some of the displays. According to several crewmembers, Waddle, when informed that equipment preparations would further delay the start of the demonstration maneuvers, "seemed frustrated that he couldn't start the maneuvers right away".

For 15 minutes, beginning at 13:15, 46 minutes after the scheduled time, Greeneville performed a series of drastic maneuvers, including high-speed, full-rudder, 35-degree turns side to side, as well as rapid up-and-down movements. Waddle personally directed the maneuvers. According to Waddle, the DVs "were loving it". Waddle adds, "I could barely suppress a smile as I watched the expressions of joy and amazement on the faces of our distinguished visitors". During the maneuvers, several civilians in the sonar room conversed with the sonar technicians, who were at the same time trying to keep track of any sonar contacts in the vicinity.