Delfin (Дельфин, Russian: "Dolphin") was the first Russian battle submarine. She was designed by Naval architect Senior Assistant Ivan Grigoryevich Bubnov, Lieutenant M.N. Beklemishev and Lieutenant I.S. Goryunov of the Construction Commission for Submarines (later the Rubin Design Bureau), laid down by Baltic plant at St. Petersburg, launched in 1902, and entered service in 1903, training officers and sailors. On 29 June 1904 the submarine sank in the Neva River by the wall of the Baltic shipyard during a test dive. The captain and 24 crewmen were killed, and 12 men were rescued.