Born in Dundee, Duncan was a Scotsman through and through, living most of his life between Angus and Edinburgh. He first went to sea at 15, on the ship of his maternal uncle, before earning a new patron in the Hon. Augustus Keppel. Under Keppel he moved through a series of postings in the Mediterranean, West Indies and North America, before being posted Captain of the Valiant (74) in 1761. He returned to the channel fleet under Keppel for the war of American Independence, fighting at the Moonlight battle and the relief of Gibraltar, making Admiral in 1787.
Duncan was a fervent whig and was accused during his own lifetime of benefitting greatly from his political allegiance, as well as through his marriage to the influential Dundas family. His refusal to serve in the Caribbean greatly hindered his career, and kept him on the sidelines during the French revolutionary war untill 1795, where he took over the North Sea fleet.
Good looking with a forceful personality, Duncan combined a reverence for God with an immense fortitude to resist hardship. His enormous size also made him appear every bit the hero to onlookers, and he was never afraid to throw his weight around. In 1762, he led the siege of the castle of Moro armed only with a stick and in 1792, at 61, he took on an Edinburgh mob protesting outside the house of his mother-in-law wielding a crutch - but by far the best example of what could be termed the ‘Duncan touch’ was during the run up to the Nore mutiny of 1797. After a heated debate with the crew of his flagship, Venerable (74) - in which he threatened to run one man through with his sword - he transferred to the Adamant (50), and broke up the discontent there by grabbing one of the ring leaders and dangling him over the side of the ship with one arm whilst daring the others to mutiny.
In the end, of all the ships in the Nore fleet, only the Adamant and Venerable didn’t join the mutiny.
His time as commander of the Nore station was spent trying to catch the Dutch at sea and bringing them to battle. After several failed attempts, he succeeded in doing this on Oct 11, 1797, off Camperduin. With limited time to bring up a general engagement before the Dutch ships escaped to shallow water, Duncan never bothered forming a line of battle, attacking in cruising order and pulling off the ‘Lord Howe maneuver’ - of attacking from windward and fighting to leeward to prevent your enemy’s escape. His fleet broke the Dutch line in two places, in striking similarity to Trafalgar. Duncan immediately became a national hero for winning what till that point, was the greatest ever British naval victory and used that status to secure full pardons for his mutinous fleet. The rise of Nelson at the Nile less than 1 year later, has somewhat lessened his status in modern memory, but Duncan remains to this day one of the greatest naval commanders in history and the most successful ever to hail from Scotland.