Admiral Adhar Kumar Chatterji (4 March 1914 – 6 August 2001) was an Admiral in the Indian Navy. He served as the 6th Chief of the Naval Staff, from 4 March 1966, until 28 February 1970. He was the first Indian officer of the navy to hold the rank of full Admiral. He is credited with the transformation of the Indian Navy. He made sweeping changes and restructured the navy, creating the Western and Eastern Naval Commands and the Western Fleet. Under him, the Indian Navy also entered the submarine age, with the commissioning of in 1967. Early life Chatterji was born in Dacca on 22 November 1914. He attended the Presidency College (as a graduating student of the University of Calcutta), graduating in 1933. The same year he saw a notice at the college about the relaxation of entry criteria for the Royal Indian Marine. He applied for and topped the Federal Public Service examination. Naval career Early career Chatterji was one of the first Indian cadet-entry officers to join the Royal Indian Navy in 1933. After training on board the Indian Mercantile Marine Training Ship (IMMTS) Dufferin, he was sent to the United Kingdom. He was commissioned into the Royal Indian Navy as a sub-lieutenant on 1 September 1935. He spent four years training on different ships. On 1 September 1938, he was promoted to the rank of lieutenant. In 1939, he was selected to specialise in anti-submarine warfare (ASW) and trained in the UK. He completed the course in August 1940 and was appointed an instructor at the ASW training school - HMS Osprey, Portland. World War II In late 1940, he was transferred to the Black Swan-class sloop . On 1 January 1942, he was appointed the first officer-in-charge of the ASW school in India - at castle barracks. He also served on board the Black Swan-class sloop . On 23 October 1944, he was promoted to the acting rank of lieutenant-commander and appointed commanding officer of the Bangor-class minesweeper . Kathiawar was a part of the Eastern Fleet, and escorted numerous convoys between Africa, British India and Australia in 1943-45. He then was appointed officer-in-charge of the radar school HMIS Chamak in Karachi. He was promoted to substantive lieutenant-commander on 1 September 1946. In January 1947, he was selected to attend the Royal Naval College, Greenwich in the UK. Post-Independence Chatterji completed the staff course