미 해군 왈, "해도에 없는 산에 박았습니다"

패시브 소나만 쓰는 항해의 본질적 한계겠네요. -- Navy Says Sub Hit Mountain That Was Not on Its Charts * Writer: Christopher Drew * Source: New York Times * Date: January 11, 2005 A nuclear attack submarine that ran aground Saturday in the South Pacific, killing one sailor and injuring 23 others, appears to have smashed into an undersea mountain that was not on its charts, Navy officials said yesterday. The submarine, the San Francisco, was cruising at high speed - about 30 knots - and was more than 400 feet below the surface when the accident forced it to blow air into its emergency ballast tanks to surface. Some of the tanks were damaged by the impact. One officer said the effort to keep the submarine afloat was initially "very touch and go." The accident occurred 350 miles south of Guam, and the vessel returned to its base there under its own power yesterday. The Navy is investigating how the crash occurred. The dead sailor was identified as Joseph A. Ashley, 24, of Akron, Ohio, a machinist's mate second class. Officials said he was thrown forward during the accident and hit his head on a metal pump casing, knocking him unconscious. He died on Sunday. Other sailors were treated for broken bones, cuts and bruises. One hurt his back. Navy officials said the vessel's hull was damaged but did not rupture. The nuclear reactor, which is in the back of the submarine, was not damaged. The officials said navigational charts are prepared from both government and commercial soundings of the ocean depths, many dating back centuries. Given the vastness of the oceans, they said, there could still be small areas that were never properly charted or where earthquakes have altered the contours. The officials said it appeared that the San Francisco, which was en route to Australia, had not strayed off course. "The initial reports are that they were using the proper charts, and they were where they were supposed to be and at the depth they were supposed to be," said a former Navy officer who was briefed on the accident. Investigators will check whether the crew made any errors, officials said. The Navy began basing attack submarines in Guam in 2002. The San Francisco, with a crew of 137, is one of three operating from there. During the cold war, attack submarines conducted regular surveillance off the Russian coast. From the base in Guam, the submarines can easily monitor naval activities by China, which some military analysts view as a potential future rival. In recent years, China has been buying diesel-powered submarines from Russia and expanding its fleet of nuclear-powered vessels. Similar accidents have happened before, in part because submarines typically do not use their active sonar systems, which emit loud pings, to navigate. Instead, submarines try to operate silently, relying on undersea charts, checks with navigation satellites and passive sonar systems that pick up the noises of other vessels.