The following is the entry for James Crawford Caffin in William O'Byrnes 1849 'Naval Biographical Dictionary'.
CAFFIN. (Commander, 1842. f-p., 17; h-p., 6.)James Crawford Caffin, born 1 March, 1812, is third son of Wm. Caffin, Esq., of the Royal Laboratory, Woolwich. This officer entered the Navy, 12 Aug. 1824 as Fst.-cl. Vol., on board the Pylades 18, Capt. Fras. Fead, from which vessel he was discharged 10 May 1825. On 18 Jan. 1826, he re-embarked, on board the Brisk 10, Capt. Chas. Hope, and, in July 1827 he became Midshipman of the Cambrian 48, Capt. Gawen Wm. Hamilton, both stationed in the Mediterranean, where he appears to have been very actively employed against the pirates in the Grecian Archipelago, and to have shared in the battle of Navarin 20 Oct. 1827. The Cambrian being ultimately wrecked while engaged in action with the pirates of Fort Carabusa, 31 Jan. 1828, Mr. Caffin next joined for brief periods, on the Home and Mediterranean stations, the Gloucester 74, Capt. Henry Stuart, Protector surveying-vessel, Capt. Wm. Hewett, Donegal 76, Capt. Sir Jahleel Brenton, Hermes steam-packet, Lieut.-Commander Andrew Kennedy, Gloucester again, Capt. Henry Coffin, and Messenger steam-packet, Lieut.-Commander Benj. Aplin. Having passed his examination, 3 Aug. 1831, he was soon afterwards appointed Mate of the Flamer, another steam-packet, Lieut.-Commander Richard Bastard, with whom he served, also in the Mediterranean, until Jan. 1834. In Oct. following he joined the Excellent, Capt. Thos. Hastings, gunnery-ship at Portsmouth, where his professional attainments, after the usual course of study, were acknowledged by a first-class certificate. He next served for upwards of two years as Gunnery-Mate of the Asia 84, Capt. Wm. Fisher, again in the Mediterranean, and, on 28 June, 1838, was advanced to the rank of Lieutenant. His following appointments were – 17 Oct. 1838, as Gunnery-Lieutenant, to the Excellent – 9 May, 1839, to the Blenheim 72, Capt. Sir Humphrey Le Fleming Senhouse, in the Channel – 10 Aug. 1839, to the Excellent again – and, 2 Oct. 1841, to the Queen 110, fitting for the flag of Sir Edw. W. C. R. Owen. In honour of Her Majesty’s visit to the latter ship, previously to her final departure for the Mediterranean, Commander Caffin was advanced to the rank he now holds, 7 March, 1842. He has been in command, since 26 Nov. 1845, of the Scourge steam-sloop, attached to the Channel squadron.
Commander Caffin (who was a student at the Royal Naval College at Portsmouth from May to Dec. 1842) is the officer who was nominated by the Admiralty to act as Joint Commissioner with Lieut.-Col. Chalmer, R.A., in the investigation of Capt. Warner’s celebrated "Long Range" and "Invisible Shells." In Feb. 1845, he was, in conjunction with Capts. Henry John Codrington and John Robb, sent out in the Black Eagle on an experimental cruize with the royal steam-yacht Victoria and Albert and Rattler (screw) steamer, for the purpose of reporting on the capabilities of those vessels. He married, 21 Sept. 1843, Fanny Brouncker, youngest daughter of Wm. Atfield, Esq., of Cosham House, Hants, by whom he has issue one son.