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By George F. Lee, Star-Bulletin
An oil slick was left behind by the Ehime Maru after its
collision with the submarine. The sub can be seen on the
surface; the Ehime Maru quickly sank after the crash in
waters the Coast Guard says are 1,860 feet deep.

Surfacing always
dangerous despite
equipment, cautions

'Water is coming in'
The missing and injured
'I am alive'
Uwajima agonizes

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By Burl Burlingame
Star-Bulletin

Although great care is exercised when submarines surface, collisions do happen, say submarine experts.

In one six-year period, from 1983 to 1989, American submarines suffered 42 collisions, many with fishing boats, according to Navy records.

Some recent sub incidents:

In 1998 a South Korean fishing boat was sunk near the port of Chinhae after colliding with the submarine La Jolla. The crew was rescued by the La Jolla.

In 1989 the USS Houston, a Los Angeles-class submarine, snagged a tug's towline during the filming of the movie "The Hunt for Red October." A crew member of the tug was killed in the accident off the California coast.

In 1988 the Japanese submarine Nadashio collided with fishing boat Fuji Maru No. 1, sinking it. Thirty crew drowned and 16 were injured in the accident.

In 1986 the USS Georgia -- a ballistic missile sub -- collided with a surface ship off Midway Island. Two civilians working on the civilian tug were lost.

In 1981 the USS George Washington, another nuclear missile sub, hit the 23,000-ton Japanese merchant ship Nissho Maru off the southern coast of Japan. The ship sank and two crew members were killed.

By Dennis Oda, Star-Bulletin
These are civilians who were guests on the USS Greeneville
when it collided with and sank the Japanese fishery training
and research vessel Ehime Maru. They spent the night on
the submarine as the Greeneville stayed at sea to help with
the search. This morning, the civilians were put on this
boat that took them to shore in Pearl Harbor.

A whirlwind of activity

How could such accidents happen?

According to Gerry Hofwolt, director of the USS Bowfin submarine museum and a former executive and commanding officer aboard nuclear submarines, the moments right before surfacing are a whirlwind of furious activity as the craft passes from the darkness of the deep sea to the open air.

"They come up very quickly to minimize transition time from one realm to another," said Hofwolt.

Typically, while running under the surface, a submarine uses passive sonar to listen to "targets" in the water around it. Every type of ship has an acoustic "signature" that identifies it and gives the submarine's computers an idea of bearing and distance.

As a submarine rises to an intermediate depth, "say, less than a hundred feet, the procedures change and more watches are stood," said Hofwolt.

"There are extra bodies around keeping extra eyes on everything." A sophisticated acoustic array watches for any maneuvers on the surface that could become a threat.

Then they rise to periscope depth, and the officer of the deck raises it quickly and takes a 360-degree look around to make sure there are no close contacts, within a hundred yards. If there are, the command given is "Emergency Deep!" and the submarine goes right back down.

"If you can't discern the horizon, it can become very difficult to estimate the size of a vessel," Hofwolt said.

"Fishing vessels also are a problem in that they start and stop, making them hard to track, and if their engines are off, they're invisible to the submarine. You'd never know they're there. Also, certain conditions create acoustic boundaries in the water, which can mask surface signals."

Even ships as large as supertankers have blind spots to submarines, said Hofwolt. "The hulls are so deep that they mask the sound of the propeller, and there's a cone of silence directly in front of the supertanker, and that's very dangerous."

"Something like this is such a tragedy," said Hofwolt. "We feel for those who are lost at sea in any circumstance."

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Reporter Gregg Kakesako
contributed to this story.