Hyundai Heavy Industries has unveiled the nation's largest submarine Son Won-il.

President Roh Moo-hyun and Defense Minister Yoon Kwang-ung on Friday attended a ceremony in which First Lady Kwon Yang-sook officially launched the new craft.

Sixty-five meters long and six meters wide, the 1,800-ton submarine can run at 37 kilometers per hour and carry up to 35 crew members.

Equipped with a torpedo and missiles, the submarine is part of the Navy's project designed to strengthen its next-generation capabilities.

Named after the late Admiral Son Won-il, the submarine will undergo test runs for a year in waters off the nation before its transfer to the Navy in November next year.