William Mirtle (24 December 1739 – c. 1769) was a Scottish mariner and explorer, primarily known for his time with the Bengal Pilot Service (or the Bombay Marine) and the British East India Company. On 22 December 1768, he was granted a coat of arms for “having been on the 7th day of January 1763 taken by a French Squadron cruising off Bengal in the East Indies and by desperate attempt overcoming the crew of the vessel whereon he was prisoner, by which success he regained his liberty and got safe to Calcutta where his critical intelligence of the enemy proved of essential service to the Commerce which the Factory testified by public thanks. After which engaging as a volunteer he served with reputation having likewise had the happiness to succeed in establishing an important fir trade for masts in the interior parts of Bengal with the Mountain Rajas”.
William Mirtle was born 24 December 1739 to Thomas Mirtle, brewer in Edinburgh, and his wife Jean Rannie. Jean was the niece of Sir David Rannie (1 July 1716 – 17 November 1764), who made a fortune with the East India Company, later returning to Scotland and purchasing Melville Castle.
At a consultation held at Fort William on 12 January 1763, Peter Amyatt Esq., President and Council of Fort William, informed the Agent Board … “that the Chowky Boat arrived at Town last night at 12 o’clock with William Mirtle on Board, late Mate of the “Speedwell” Snow (under) Captain Ramsay, who brings the following intelligence: Namely, that they were taken on the 7th Instant in 25 fathoms of water by a French Squadron consisting of two Ships & Frigate which is cruising in Balasore & has made besides the following Prizes Vizt. The “Walpole”, bound to Madras, the “Grampus” Pilot Sloop, Mr. Savage Pilot, & a Sloop from Chittagong supposed to be the “Clive”. That he (Mirtle) on the morning of the 9th repossessed himself of the “Speedwell” & was pushing in for the River, but finding he was in danger of being again taken by the French Frigate he took to his Boat with ten Lascars and made his escape.”
In the debate that followed it was decided that several ships should remain at Kedgeree, but that Pilots should be sent aboard them with instructions to sail up the Hooghly River if the enemy attacked, and that twenty sepoys should be detailed to each ship as a further safeguard. It was also decided to send a sloop to cruise off Palmyras Point to warn inbound ships, and that another sloop (well armed and manned) should watch the motions of the French squadron and annoy any boats or sloops they may send into the river.
The only other event of importance during the French squadron’s visit to Balasore was a fight with the East Indiaman Winchelsea, which escaped after an engagement lasting for two hours.