Originally from Dunbar, Duncan`s experience at sea started when, as a youngster, he sailed on ocean bulk carriers with his father. This saw him traveling to various parts of the world.

Duncan skippered his own charter boat before going offshore to work on a multi-role vessel, where he was soon made an offshore coxswain.

He joined the RNLI in 1987 and was promoted to Emergency Coxswain in 1995. Duncan commanded various different classes of lifeboat before being appointed to Dover in 2003.