SEOUL, March 27 (Yonhap) — A South Korean navy ship sank off the west coast near its maritime border with North Korea, officials said Saturday, prompting President Lee Myung-bak to convene a late-night meeting of security-related ministers. The 1,500-ton ship “Cheonan” went down around 9:45 p.m. near a South Korean island in the Yellow Sea, and 58 of the 104 crew members on board have been rescued so far, navy officials said.