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USS Dolphin (AGSS 555). Fire broke out on the research sub early today.

Navy Research Sub Burns in Pacific

The U.S. Navy's only operational research submarine caught fire and flooded 160 kilometers off the California coast early this morning. The 43 crew members, including two civilians, escaped, but damage to the sub's research capabilities is still being assessed.

The USS Dolphin (AGSS 555) is the world's deepest diving submarine, having set a depth record of over 900 meters shortly after its deployment in 1968 (although small submersibles have gone deeper). It is also the Navy's only remaining diesel-powered submarine, as all newer subs are nuclear powered. Its deep-diving ability has allowed the 50-meter sub to conduct unique research, including oceanic surveying and deep-water acoustic studies. The Dolphin has also been extensively involved in the development of weapons and other technology, and it has been important in testing sonar systems. Much of its research and development are military, but civilian researchers have conducted work from it as well.

The sub was engaged in a military exercise when the fire first broke out at 11:30 last night, says Lt. Kim Marks, spokesperson for Submarine Squadron 11, based in San Diego. Navy officials could not immediately say whether the sub was currently outfitted for scientific research and, if so, what projects may have been disrupted. The cause of the fire is under investigation, and ships are presently assessing damage to the sub while it remains floating in the ocean off San Diego.

Related sites
Navy fact sheet on the sub
More info on the sub and its research, from the Federation of American Scientists U.S. Navy News, for news updates on the situation