 Maitland went on to be commanding officer of the third-rate HMS "America" off the coast of Portugal in November 1846, commanding officer of the first-rate HMS "San Josef", flagship of Admiral Sir William Gage serving as Commander-in-Chief, Plymouth, in April 1848 and commanding officer of the second-rate HMS "Impregnable", Gage's new flagship, in January 1849.After that he became commanding officer of the second-rate HMS "Agamemnon" in the Channel Squadron in September 1852, commanding officer of the first-rate HMS "Victory", flagship of Admiral Sir Thomas Cochrane serving as Commander-in-Chief, Portsmouth, in December 1853 and commanding officer of the Gunnery School HMS "Excellent" at Portsmouth in January 1854.Promoted to rear-admiral on 18 June 1857, Maitland gave evidence to the Royal Commission on the Defence of the United Kingdom in 1859 and argued that building powerful ships was more important than building fortifications.