Two U.S. sailors died after waves swept them from the deck of a nuclear submarine off the coast of southwestern England on Friday, British coast guards said. The USS Minneapolis-St. Paul was leaving Plymouth harbor in rough weather around midday, said Sean Brooks, a coast guard spokesman. Four sailors were tied to the vessel with ropes — a routine precaution — but two fell into the surging water. British rescue boats picked up all four, Brooks said. The nuclear-powered attack submarine, which is based in Norfolk, Virginia, has a crew of 110 and can reach speeds exceeding 30 mph. Its weapons include torpedoes and Tomahawk cruise missiles. Sixth Fleet is the operational arm of U.S. Naval Forces Europe and is primarily responsible for the Mediterranean and western and central Africa.