Poor surveillance by night-duty officers and bad teamwork caused the fatal collision between a Maritime Self-Defense Force destroyer and a fishing boat off Chiba Prefecture last year, the Defense Ministry said in a report released Friday.
The report describes a pattern of sloppy navigation by the Atago’s crew, which had been warned before about its inadequate watch performance during poor visibility.
To prevent similar accidents, the report recommends improving the quality of surveillance, bolstering teamwork among navigation personnel, and enhancing overall navigation through periodic evaluations and training.
Defense Minister Yasukazu Hamada on Friday took disciplinary action against 38 people involved in the accident.
The 35-page report — the product of a 15-month inquiry by the ministry’s accident investigation commission — was issued a month after prosecutors charged two Atago officers with professional negligence resulting in the death of the father-and-son fishing crew.
By interviewing some 80 people, including the indicted officers, the report delves into why the 7,750-ton Aegis destroyer collided with the 7.3-ton Seitoku Maru off the Boso Peninsula in the predawn hours of Feb. 19, 2008.
The report’s authors found that Lt. Cmdr. Tomohisa Nagaiwa, 35, the chief night-duty officer at the time of the accident, “failed to maintain continuous watch on the fishing boat after casually determining that it posed no collision risk due to the direction it was bearing.”
The chief antisubmarine warfare officer also failed to instruct radar operators to properly scan the water for vessels and failed to tell lookouts to keep an eye out for them, the report says.
As the other direct factor leading to the collision, the report cited insufficient coordination on the Atago’s bridge and between it and the radar-equipped Combat Information Center below deck.
Nagaiwa’s deputy did not tell a lookout to keep watch on specific vessels, and others on the bridge failed to convey information about the vessels to radar operators, the report says.
Several other factors led indirectly to the collision, it says. Chief among them was the action by Lt. Cmdr. Keitaro Ushirogata, 36, the chief navigator, who was on night duty just before Nagaiwa replaced him.
During the change of duty, Ushirogata wrongly told his colleague that vessels ahead and to the starboard side of the Atago posed no collision risk because they were not moving, the report says.
Ushirogata had earlier spotted a group of three small vessels around which the Seitoku Maru is believed to have been, on the radar but deleted their symbols from the screen after concluding they were either stationary or moving slowly, the report says.
Nagaiwa and Ushirogata were indicted last month on grounds that their overlapping errors led to the accident. Ushirogata’s indictment was surprising because crew members not operating a ship at the time of a collision are rarely indicted.
The report also blames their supervisors, including Capt. Ken Funato, 54, skipper of the Atago at the time, and another captain who commanded the 63rd Escort Division, to which the destroyer belonged at the time of the accident, for failing to properly supervise the crew.
The Yokohama Marine Accident Tribunal concluded in January that Nagaiwa, the officer in charge at the time of the accident, was partly responsible for the collision. But it let Ushirogata off the hook by determining that he played no role in causing the accident.
The Defense Ministry’s report puts the blame squarely on the Atago crew and others in the MSDF for the accident, even though the MSDF side had told the tribunal the fishing boat was the primary cause of the collision.
The MSDF side alleged during the trial-style proceedings that the boat made an abrupt turn and accelerated just before the accident.
“Unlike a marine accident tribunal, which must paint things in black and white or get to the bottom of an accident, our mission was to find where our problems lay and what we must do from now on,” a senior Defense Ministry official said of the report.
According to the report, the Atago collided with the Seitoku Maru about 42 km south of Cape Nojima at around 4:07 a.m. The two fishermen on the boat — Haruo Kichisei, 58, and his 23-year-old son, Tetsuhiro — went missing and were later declared dead.
MSDF Chief of Staff Adm. Eiji Yoshikawa was sacked after the accident. Six crew members, including skipper Funato, were removed from duty around the same time.
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