The following is the entry for William Fanshawe Martin in William O'Byrnes 1849 'Naval Biographical Dictionary'.
MARTIN. (Captain, 1824. f-p., 18; h-p., 16.)William Fanshawe Martin is eldest son of Admiral Sir Thos. Byam Martin, G.C.B.
This officer entered the Navy, 15 June, 1813, as Fst.-cl. Vol., on board the Prince Frederick 74, Capt. Rich. Pridham, in which ship, and in the Impregnable 98, and Akbar 50, each bearing the flag of his father, he served at Plymouth and off the Scheldt until April, 1815. He then became in succession attached, for short periods, to the Glasgow 50, Capt. Hon. Henry Duncan, Spencer 74, Capt. Richard Raggett, Rochfort 74, Capt. Sir Archibald Collingwood Dickson, and Eridanus 36, Capt. Wm. Paterson, all on the Channel station; and on next, in Jan. 1816, joining the Alceste 38, Capt. Murray Maxwell, he sailed in that ship with Lord Amherst for China – continuing in her until wrecked in the Straits of Gaspar, on her passage home, 18 Feb. 1817. In the following Aug. Mr. Martin was rated Midshipman of the Prince Regent yacht, Capt. Sir Edw. Hamilton. He was promoted (after nearly three years’ servitude in the Mediterranean in the Glasgow 50, Capt. Hon. Anthony Maitland) to a Lieutenancy, we believe, in the Forte 44, Capt. Sir Thos. John Cochrane, 15 Dec. 1820; and, on 7 April, 1821, he joined the Aurora frigate, Capt. Henry Prescott, fitting for South America; where, on 8 Feb. 1823, he was made Commander into the Fly sloop. He attained Post-rank 5 June, 1824; and was subsequently appointed – 29 April, 1828 to the Samarang 28, on the Mediterranean station, whence he returned in the summer of 1831 – and, 19 July, 1844, and 80 Jan. 1845, to the Queen 110, and Trafalgar 120, flag-ships of Sir John Chambers White and Sir Edw. Durnford King, at Sheerness. He has been on half-pay since Oct. 1845.
Capt. Martin married, first, 24 July, 1826, Hon. Anne Best, daughter of the late Lord Wynford, Lord Chief Justice of the Court of Common Pleas, and sister of Capt. Hon. Thos. Best, R.N. That lady dying in 1836, he married, a second time, 21 May, 1838, Sophia, second daughter of Rich. Hurt, Esq., of Wirksworth, Derbyshire. He has issue by both marriages. Agent – J. Chippendale.