1764-1805. He was born on or about 1 February 1764 in Banff, Scotland, the younger son of a solicitor, James Duff, who was related to the Earl of Fife. His mother, Helen Skene, died six weeks after his birth. He was a great nephew of Vice-Admiral Robert Duff.
Duff spent much of his childhood exploring the harbour and waters around Banff, and when he stowed away aboard a merchant vessel on a voyage to a nearby port his tutor was ordered to prepare him for a career in the Navy. Accordingly in September 1777 he joined the Panther 60, Captain John Harvey, flying the flag in the Mediterranean of his great-uncle, Rear-Admiral Robert Duff. Whilst still on this station his kinsman commissioned him lieutenant of the Enterprise 28, Captain Sir Thomas Rich, on 15 September 1779.
He was present at the Moonlight Battle off Cape Finisterre on 16 January 1780, and continued his service in the Leeward Islands aboard the Montagu 74, Captain John Houlton. When this ship was driven out to sea from her anchorage at St. Lucia and dismasted during the Great Hurricanes in October Duff suffered an injury to his leg that resulted in some discomfort for the rest of his life. Continuing on the Montagu, he is said to have participated in the Leeward Islands campaigns of 1780-2, including the reduction of St. Eustatius on 3 February 1781 and the Battle of Fort Royal on 29 April under Captain Houlton, and following that officer?s replacement by Captain George Bowen he fought at the Battle of Chesapeake Bay on 5 September 1781, the Battle of St. Kitts on 25 January 1782, and the Battle of the Saintes on 12 April.
During 1784 he was employed aboard the sloop Camilla, Captain John Hutt, returning from Jamaica and then sailing there again where he saw further service, including aboard the Europa 50, Captain James Vashon, with the broad pennant of Commodore Alan Gardner. His long years in the West Indies, and in particular the re-opening of the wound to his leg, brought about his return to Scotland in 1787, where after a period of convalescence he was soon restored to good health.
In 1790 Duff managed to obtain the interest of the Duke of Gordon and through him the influential Henry Dundas, the treasurer of the Navy. This resulted in his promotion to commander along with many other lieutenants on 21 September, and having kissed the King?s hand on 13 October he joined the new sloop Martin 16 at Woolwich, serving on the east coast of Scotland, and taking pressed men into Portsmouth from Leith in May 1791 before returning north in the following month. A more pleasant experience was the embarkation of the Duke of Gordon for a cruise to the northern islands in September. During 1792 the Martin grounded on the beach at Shields after arriving to help quell a riot amongst the seamen there, but this did not prevent the rioters from coming aboard the vessel to help refloat her. She left Newcastle for Scotland at the end of November, and Duff continued with her until the beginning of the following? year.
In January 1793 he appears to have been employed in manning the Nemesis 28 at Portsmouth, and he was posted captain on 9 February to the Resource 28. However, whilst this frigate was still fitting out he was prevailed upon to relinquish the command by the Earl of Chatham, the first lord of the Admiralty, and he removed shortly afterwards to the Duke 98, which flew Commodore Hon. George Murray?s broad pennant in the unsuccessful campaign against Martinique and other Leeward Islands during March -June. After the Duke came home with most of Gardner?s force in September Duff briefly commanded the Glory 98 in early 1794, and in September he joined the eighteen year-old Ambuscade 28 at Woolwich, serving thereafter in the North Sea and Downs.
In April 1796 Duff commissioned the new fir-built eighteen-pounder frigate Glenmore 36 at Deptford, the timber for which had come from the Great Glen, and which was predominantly officered by Scots. Serving initially in the North Sea, she arrived at Elsinore in early December to collect the Baltic convoy and escort it back to Leith before in February she carried Admiral Adam Duncan from that port to Great Yarmouth to assume command of the North Sea Fleet. Shortly afterwards Duff reported to the Admiralty that the Dutch fleet had made its departure from the Texel.
During 1797-8 the Glenmore was based on the Irish station, and she later went out to the West Indies where she took several prizes. On 17 December 1799 she recaptured the outward-bound East Indiaman Calcutta from the French frigate Sir?ne 36 and corvette Berg?re 18 off Porto Santo, Madeira, but Duff was later subjected to some criticism for not assisting his smaller consort, the Aimable 32, Captain Henry Raper, in the pursuit of the two French vessels. In his defence it was cited that he believed the Calcutta to be a cut-down ship of the line and had directed his attention to her as a result. In March 1800 the Glenmore was docked at Plymouth, and in June she sailed from the Devonshire port to join the Channel Fleet.
In March 1801 after a brief period aboard the Courageux 74 in the Channel Fleet under the orders of Rear-Admiral Sir Robert Calder, Duff transferred to the Vengeance 74, which initially departed Yarmouth in April for service with the Baltic fleet under Admiral Sir Hyde Parker, but then joined the North Sea fleet. On 17 August she entered Portsmouth, where aboard the Gladiator 44 on 1 September Duff sat on the court-martial into the loss of the Hannibal 74 at the Battle of Algeciras on 6 July. In December the Vengeance was present when a mutiny broke out in Bantry Bay, although she remained conspicuously loyal, and Duff was even able to allow his men liberty ashore when she returned to Portsmouth on 1 January 1802. Later that month she went out to the West Indies with Rear-Admiral George Campbell?s squadron, and at the end of June she returned to Portsmouth to be paid off.
Upon the resumption of hostilities with France in 1803 Duff was not immediately re-employed, so instead he voluntarily gave his services in advising on the defences in the Firth of Forth. In April 1804 he was appointed to the Mars 74 in place of the promoted Rear-Admiral John Sutton, and arriving at Plymouth in May he took passage out to join her, serving thereafter off Ferrol. After returning to Plymouth to refit and victual in August the Mars sailed two months later to join the Channel Fleet, and in the following winter she saw service both off Rochefort and off Brest.
In April 1805 the Mars re-entered Portsmouth, and she was subsequently one of the first ships sent out to reinforce Vice-Admiral Lord Collingwood when the Franco/Spanish fleet under Vice-Admiral Pierre Villeneuve entered Cadiz in August. Duff later raised a broad pennant in command of a detachment of vessels relaying signals between the inshore squadron and the fleet further out to sea under Vice-Admiral Lord Nelson.
At the Battle of Trafalgar on 21 October the Mars was placed second in line to Vice-Admiral Cuthbert Collingwood?s flagship Royal Sovereign 100, and she was badly damaged by the Fougeuex 74, Monarca 74 and Alg?siras 74, being raked by the latter two in attempting to avoid the Santa Ana 112. Duff was then be-headed by a double-headed shot from the Pluton 74 which had joined the assault upon her, and he became one of twenty-nine men killed and sixty-nine wounded on his ship. Bizarrely his headless corpse was lifted high in an act of defiance by the crew and was then left on the gangway covered by a flag until the end of the battle when his son, Norwich Duff, helped carry it below.
Duff was buried at sea, and his son, who was erroneously reported to have also been killed, took passage home aboard the Euryalus 36, Captain Hon Henry Blackwood. When Edinburgh was illuminated to celebrate the Trafalgar victory Castle Street, where Duff had his residence, was kept conspicuously dark. A monument was later erected to his memory in the crypt of St. Paul?s Cathedral.
He married his childhood sweetheart, Sophia Dirom of Muiresk, Aberdeenshire, at Fintray, Aberdeenshire, on 6 May 1791 and had issue two sons and three daughters. His eldest son, Norwich Duff, born in 1793, fought with him at Trafalgar and became a vice-admiral.
Duff was Scottish, was described as looking so, and did his best to populate his ships with his countrymen. Well-built and over six feet tall, he cut an imposing figure. He was well regarded, particularly by Vice-Admiral Lord Nelson, was a popular, genial man, and a favourite of Vice-Admiral Lord Collingwood, as well as being on friendly terms with Captains Alan Hyde Gardner, William Henry Jervis, John Cooke, and Sir Richard Bickerton. Renowned for keeping a frugal table, he claimed to be a poor man who had earned little prize money, although some viewed him as wealthy. He wrote on an almost daily basis to his wife.