Somerled Macdonald was born in Woking, Surrey, (3^rd Quarter 1904) the son of John Doran Macdonald (an Automobile Engineer) and Katherine Alleyne Macdonald (née Borthwick). At the time of the 1911 Census the Macdonald family were living at The Whins, Hook Heath, Woking., Surrey. His father later of Harfield, Hambledon, Hants, was serving as a 48 year old Temporary Captain, Special List, with the Graves Registration Commission (GRC) when he was killed on 18 March 1916 whilst charting War Graves on the Menin Road in France.

Somerled Macdonald joined the Royal Navy as a Cadet on 15 May 1918 and, at the time of the 1921 Census, he was listed as a sixteen year old Naval Cadet serving in the Royal Naval College, Dartmouth. After promotion to Midshipman he served in the battleships HMS CENTURION and HMS EMPEROR OF INDIA from 15 September 1922 to February 1925 before taking his Courses and Examinations for the rank of Lieutenant.

Having volunteered for service in submarines he was appointed to HMS DOLPHIN ‘for Submarine Training’ from October 1926 to 14 February 1927. On completion of his training he served in HMS L52 from February to April 1927 and then in ‘Submarine L69 as 3^rd Hand’ until 20 June 1927 before being sent to the Far East to join the Submarine Depot Ship HMS TITANIA at Hong Kong ‘for Submarines’ where he served until July 1928.

Somerled Macdonald then returned home and was appointed to HMS PEMBROKE at Chatham ‘for Submarine L7’ but only for a week from 1 August 1928 before he joined the Submarine Depot Ship HMS VULCAN at Portland  ‘for Submarine H44 as First Lieutenant’ serving there until 12 August 1929. He next served in the battleship HMS REVENGE from 19 August 1929 to August 1930. After training courses at HMS VICTORY, the Royal Naval Barracks at Portsmouth, he returned to submarines with an appointment to HMS DOLPHIN ‘as Spare Submarine First Lieutenant’ on 10 November 1930 and then to the Submarine Depot Ship HMS LUCIA – also as ‘as Spare Submarine First Lieutenant’ on 8 January 1931.

He was further appointed to HMS DOLPHIN ‘for Submarine M2 as First Lieutenant’’ on 26 April 1931. HMS M2 was lost with all hands on 26 January 1932. The submarine had been carrying out exercises in West Bay off the Dorset coast and is believed to have been flooded through the aircraft hangar – whilst in the act of surfacing to fly off the Parnall Peto aircraft. Somerled Macdonald who was unmarried was lost in the accident.