Colin James Buchanan was born at Abbotabad in India on 15 October 1890, the son of Brigadier General Kenneth James Buchanan CB and Ethel Mary Buchanan (née Walker). On 13 June 1909 he was indentured to the Anglo American Oil Company for three years serving in the SS Marere, the square riggers Glendoon and Eclipse and SS Iroquois. He served as Second Mate in the Barque Inverlyon from 5 September 1912 to 13 July 1913 and as Second Mate in the barque Port Jackson on the Rotterdam-Australia run from 2 September 1913 to 7 July 1914.

Temporary Acting Sub Lieutenant Colin Buchanan, Royal Naval Reserve was appointed to HMS C33 at Dover as Third Hand on 20 August 1914. This was to be his first (and only) submarine appointment. On 4 August 1915 HMS C33 was operating in conjunction with the trawler MALTA in an operation against the U-Boats. In the early evening, the two vessels parted company. After a wireless message later the same evening, nothing more was heard from C33. It is believed that the submarine strayed into a minefield, hit a mine and was lost with all hands.

Colin Buchanan was the husband of Clarice Grace Buchanan (née Prosser) of Young Street, Wallaroo, South Australia and the father of Colin Thomas Buchanan (born 28 September 1914). He is commemorated on the Portsmouth Naval War Memorial on Panel No 9 and in the Cemetery at Wallaroo, Copper Coast, South Australia.