How could submarine have failed to detect boat?
© St. Petersburg Times, published February 12, 2001
HONOLULU -- The rapid ascent the USS Greeneville was making when it struck and sank a Japanese ship Friday must be preceded by a careful scan that the captain is solely responsible for overseeing, current and former submarine commanders said.
They said Sunday that Cmdr. Scott Waddle, who has been reassigned pending the outcome of the investigation, likely will never command another Navy ship -- even if he is cleared of any wrongdoing.
A central question in the investigation, Navy and civilian officials said, would be how or whether the crew of the 360-foot submarine, the Greeneville, could have failed to detect the presence overhead of the Japanese vessel, the Ehime Maru, before surging to the surface in a breaching maneuver known as an emergency main ballast blow.
Careful sonar scanning and a look through the Greeneville's periscope immediately before the rapid ascent should have revealed the presence of the Ehime Maru in the submarine's practice area. When other vessels are nearby, the rapid ascent should not be performed.
Nine people, including four high school students, aboard the Ehime Maru remain missing, and the trawler's captain said they were below decks when the ship quickly sank. The Coast Guard said it would continue searching for them, while Japanese Prime Minister Yoshiro Mori suggested raising the wreckage from 1,800 feet.
The Greeneville's rapid ascent drill occurred in waters with heavy traffic from pleasure vessels and ships traveling among the Hawaiian islands.
The emergency main ballast blow is described by those who have experienced it as one of the most thrilling sensations at sea. The super-rapid ascent from hundreds of feet below the ocean surface sends the submarine rocketing through the water and then breaching like a whale.
"It is really quite a ride," said James H. Patton Jr., a retired Navy commander who skippered the USS Pargo, a Sturgeon-class submarine. "It's like an elevator, and the ascent is very, very rapid. You've seen the pictures, where the submarine comes out of the water a third of its length."
But the maneuver is filled with potential danger for ships in the area and must be exercised with extreme caution, the submarine commanders said.
The precautions of the captain and crew of the Greeneville are the subject of Navy and National Transportation Safety Board investigations.
The Greeneville struck the Ehime Maru with the force of an unarmed torpedo. The vessel sank in minutes, its engine room torn open.
While the investigations have just begun, several current and former Navy officers say it is the captain's responsibility to be sure his surfacing submarine is not going to hit another vessel.
The nuclear-powered Greeneville, a Los Angeles-class attack submarine, left its home port in Pearl Harbor at 8 a.m. (1 p.m. EST) Friday for a daylong routine training mission. In addition to the crew of some 100 Navy personnel, 15 civilians were along.
Taking riders on a quick training mission is a Navy tradition that keeps the public, the news media and dignitaries informed of the Navy's capabilities and lets it display its expensive hardware. Navy spokesman Sunday declined to identify the civilians aboard or to reveal their affiliations.
Submarines such as the Greeneville routinely practice the emergency main ballast blow, usually about four times a year. Former submarine officers said it is not unusual to perform such a drill with civilians aboard.
A submarine submerges as its expels air from its ballast tanks and fills them with water. Once filled with water, submarines prowl by using their engines and trim blades. In an emergency ballast blow, the ballast tanks are quickly -- in seconds -- flushed of seawater and filled with air from pressurized tanks. The air in these tanks are typically pressurized to 4,500 pounds per square inch. A car tire is filled with air to about 30 pounds per square inch.
Before performing the emergency ballast blow exercise, a submarine will typically surface to periscope depth, some 60 feet below the surface.
The eyes peering through the periscope are typically the skipper's or those of the officer on deck. When the Greeneville was practicing this maneuver, about nine miles south of the Oahu landmark of Diamond Head, daytime visibility was good, though the seas were choppy, with swells of 6 to 8 feet. A scan by a periscope should have been able to see at least 10 miles in all directions.
Sonar should also have been employed. The captain of the Ehime Maru, Hisao Onishi, said his ship's engines were running at the time of the accident at 11 knots, or 12.6 mph. This would have given off the distinct "pings" and "turns" of a rotating propeller. The Ehime Maru, moreover, was 180 feet long and stood high in the water.
"Our normal procedure, which has been tested over the years, is to do an acoustic and visual search of the surface," said Adm. Thomas Fargo, commander of the Pacific Fleet and former sub commander.
After the sonar and periscope scans, a captain would order the submarine to dive to 400 feet or so and then give the order to perform the emergency ballast blow.
After the "chicken switches" in the main control room were hit, those aboard would feel a jolt, and the ship would ascend rapidly, at an angle of 15 to 25 degrees and speed of 10 to 15 knots, or 11.5 to 17.25 mph.
Submarine commanders said investigators will focus on what, if anything, the captain and crew saw through their periscope and heard on sonar. Some possibilities are that the fishing vessel changed course or speed, that it was not seen or heard, that the submarine's officers did not look long enough or that after descending from periscope depth the Greeneville idled too long below before resurfacing.
Meanwhile, relatives of the Japanese fishermen and students missing brought their vigil to Hawaii on Sunday as rescuers continued searching. Thirty-four family members and officials traveled from Osaka to be with survivors and await word of the three crewmen, two teachers and four students who disappeared.
Five Coast Guard and Navy aircraft and four vessels were conducting the search that covered more than 5,000 square miles.
PRIME MINISTER CONTINUED GOLF: Japanese Prime Minister Yoshiro Mori was berated by a leader of his coalition Sunday for taking two hours to finish a round of golf after hearing about the submarine accident that left nine Japanese missing.
"I think he should have stopped playing golf immediately and returned to his office," Takenori Kanzaki, leader of the New Komei Party, said on a Fuji Television news program.
Mori defended his decision.
"It would not get any of us anywhere if I rushed and got all flustered," he was quoted as saying by the Kyodo news agency. Remaining where he was, he said, was "the safest course of action."
- Information from the New York Times and the Associated Press was used in this report.
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