HONOLULU -- A crew member plotting sonar readings on a U.S. submarine that collided with a fishing vessel has told investigators he briefly stopped performing the task because he was distracted by civilian guests in the control room.
The National Transportation Safety Board also said Tuesday that the Navy has determined the submarine's sonar crew detected the Japanese boat 71 minutes before the submarine collided with it while performing an emergency rapid-ascent drill.
NTSB member John Hammerschmidt said three crew members in the USS Greeneville's sonar room worked uninterrupted to monitor ships in the area south of Oahu.
But the fire control technician, who plots the submarine's position using sonar contacts, told investigators his duties were interrupted less than an hour before the collision with the Ehime Maru, Hammerschmidt said.
"He ceased this updating of the CEP (Contact Evaluation Plot) because of the number of civilians present," Hammerschmidt said.
That day, the control room was filled with 16 civilians touring the Greeneville.
Hammerschmidt would not say whether investigators believe the crew member's temporary absence from his plotting duties was a factor in the accident.
"In terms of how important it was, we do not know at this point," he said.
According to the Navy's findings, the Greeneville gained passive sonar contact with a surface vessel at 12:32 p.m. Feb. 9 and designated the contact as Sierra 13. Hammerschmidt said the Navy reconstructed the path of the Ehime Maru and determined that Sierra 13 was the Japanese ship.
Despite several periscope sweeps before the rapid ascent, the submarine crew did not spot the Ehime Maru. When the submarine surfaced, it tore through the ship's hull, sinking the 190-foot commercial fishing and training vessel within minutes.Twenty-six people were rescued, but nine are missing and presumed dead.
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