William Kennish
William Kennish (1799-1862) was born in Cornaa in the Isle of Man, and joined the Royal Navy in 1822.
Initially speaking only in his native Manx Gaelic, within 7 years he had risen through the ranks to become the master carpenter to the RN Mediterranean Fleet.
He invented a marine theodolite which led to his 'Method for concentrating the Broadside of a Ship Of War' to be so successfully trialled. He had numerous other inventions to his credit, including various pumps, a pneumatic sounding instrument, a propeller. He also advised on important construction projects in the USA.
For much more information, see here [1] and the 2011 biography 'William Kennish: Manninagh Dooie - True Manxman' by Robert W. Stimpson.