Hennah is one of those who had greatness thrust upon him. At approximately the same moment that Lord Nelson received his fatal wound, Captain George Duff of hms Mars (74) was decapitated by a cannon ball fired from the French ship Fougueux. Hennah, as first lieutenant, assumed command.

William Hennah was born the son of the Revd Richard Hennah, Vicar of St Austell, Cornwall, and domestic chaplain to Viscount Falmouth. It is recorded that he was baptised on 7 January 1768. The Gentleman’s Magazine states briefly that ‘he entered the Navy under Wallis the circumnavigator.’ He was made lieutenant in 1793. Little or nothing appears to be reported of his early career until 17 November 1800, when he first made a name for himself in command of a gallant boat action at Morbihan, in which the French corvette Réloaise was boarded and destroyed. As the historian William James remarked, ‘The enterprise thus entrusted to Lieutenant Hannah was conducted with great judgement and gallantry.’

On 19 October 1805, hms Mars was the first ship to hoist the signal No 370 – ‘The Enemy’s ships are coming out of port, or are getting under sail.’ On the 21st, she sailed third in Collingwood’s column between the Belleisle and Tonnant. Trying to find an opening in the enemy’s line, she was fired upon by the French Pluton. To avoid a collision with the Spanish Santa Ana, the Mars was obliged to turn her head to the wind, thus exposing her stern to the guns of another Spaniard, the Monarca, and the French Algésiras, which punished her severely until the Tonnant was able to come to her aid. The Mars with difficulty paid off, only to be further punished by the broadsides of the French Fougueux, one of whose shots took off Duff’s head.

Hennah fought the Mars as well as he was able, given its damaged condition. Including her captain, a total of ninety-eight officers and men were killed or wounded at Trafalgar. For his role at Trafalgar, Hennah received a sword from the Lloyd’s Patriotic Fund (the naval gold medal was presented to Duff’s widow). On 1 January 1806, he was promoted captain. He also received the unusual honour of a Letter of Commendation from the ship’s company. In 1815, he was made a Companion of the Order of the Bath. Marshall merely records he had ‘a large family’ but at least three of their children were born in Tregony, on the Roseland peninsula, Cornwall.

Captain William Hennah CB died at Tregony on 23 December 1832. The Times, in a short obituary, described him as ‘one of the old school of British sailors, having entered the Navy under Wallis, the circumnavigator and finished his active career in the wake of Collingwood at Trafalgar.’

AJC