1735-81. Born on 21 August 1735 at Swilly, near Stoke Damarel, Plymouth, he was the second son of William Furneaux and his wife Susanna Willcocks.
Furneaux’s early service in the Seven Years War was off France, Africa and in the West Indies, seeing duty as a midshipman aboard the Marlborough 80, being commissioned lieutenant on 19 October 1759 of the Edinburgh 64, Captain William Langdon, and seeing further duty in the Mélampe 36 and the sloop Ferret.
From 1766-8 he was the second lieutenant of the Dolphin 24, Captain Samuel Wallis, which vessel sailed around the world in company with the Swallow, Commander Philip Carteret. Because of illness to both Wallis and his lieutenant Furneaux often found himself commanding the vessel, and to him fell the honour of stepping ashore at Tahiti on 25 June 1767 to claim the island for King George.
Towards the end 1770 he was serving as the third lieutenant of the Trident 64, Captain Broderick Hartwell, and with the Falkland Islands dispute being resolved he joined Captain Wallis once more as second lieutenant of the Torbay 74.
On 28 November 1771 he was appointed commander of the Adventure, which sailed on 13 July 1772 with Captain James Cook’s Resolution on the latter’s second voyage of exploration. When the two ships became separated on 8 February 1773 Furneaux independently explored the coasts of Van Dieman’s Land. After rejoining Cook on 18 May in Queen Charlotte Sound, New Zealand, the two parted company again on 22 October, and shortly afterwards Furneaux had the misfortune to lose some members of his crew to a cannibal race in Queen Charlotte’s Sound. He returned to Spithead on 14 July 1774, bringing with him a Society islander, Omai, who quickly became a favourite of the British establishment, being introduced to the King at Kew by the Earl of Sandwich on 17 July, and taking residence with Joseph Banks. On completing his return voyage Furneaux became the first man to circumnavigate the globe in both directions
On 10 August 1775 he was posted captain of the Siren 28, which he commissioned at Chatham and took out to North America that winter, and in which he captured an American brigantine on 15 April 1776 bound from Philadelphia to Charleston with a company of artillerymen, most of whom immediately joined the King’s service. On 28 June he commanded the Siren in Commodore Sir Peter Parker’s unsuccessful attack on Charleston, in the course of which she grounded but was able to haul off.
During 1777 the Siren escorted the trade to Antigua before returning to New York, but she drove aground in poor weather when escorting a convoy of victuallers near Point Judith, Rhode Island on 6 November, and after coming under fire from colonial artillery was abandoned with the loss of five men killed and twenty wounded. Furneaux and the rest of his men got away in the boats to be detained by the Americans, but any hopes the rebels had of re-floating the Siren were abandoned when she was set alight by British men-of-war coming down from Rhode Island.
After being released from imprisonment in the following April Furneaux saw action as a volunteer aboard the Isis 50, Captain John Raynor, in operations off Rhode Island in August 1778 when that vessel was attacked by the César 74.
Furneaux was to live for just another three years, dying at Swilly on 19 September 1781 and being buried in the local church. He was unmarried.
He was described as being genteel and agreeable and was regarded as kind and humane by his men. Some commentators described him as a cautious navigator and explorer.