William Mends was born at Plymouth into a naval family. He married Melita, third daughter of Dr Joseph Stilon M.D. R.N. on 6 January 1839. The doctor was born Giueseppe Maria Joseph Stilon, a native of Calabria and a Royal Naval surgeon in Malta.[3]
On 8 November 1846 he was promoted to commander, serving in HMS Vanguard from 1 January 1848 to March 1849 once more in the Mediterranean, under Captain George Frederick Rich,[4] and then from 11 July 1850 on HMS Vengeance commanded by Henry Martin Blackwood at Portsmouth.
Mends was promoted to captain on 10 December 1852. He served from 22 October 1853 to 1 January 1854 as captain of HMS Agamemnon, flagship to Rear-Admiral Edmund Lyons of the Mediterranean fleet, during the Crimean War. From January 1854 he was captain of HMS Arethusa serving in the Black Sea.[5] Between 14 February 1855 and April 1857 he was captain of HMS Royal Albert, flagship to Edmund Lyons in the Black Sea and then the Mediterranean.
From 3 April 1857 to 1 February 1860 he was captain of HMS Hastings on Coast Guard service. He moved to take command of HMS Majestic on 1 February 1860 when she replaced Hastings on coast guard service and was then appointed deputy controller general of the coast-guard in 1861. He spent May 1862 to February 1883 as Director of Transport at the Admiralty.
Mends retired at the rank of rear-admiral on 1 January 1869, was promoted to vice-admiral on 1 January 1874 and then a full admiral on 15 June 1879.
^Cassar, Paul (1981). "Giueseppe Maria Stilon". Malta History - [p.93] Oversea Medical Graduates and Students at the University of Malta in the Nineteenth Century. Archived from the original on 6 June 2019. Retrieved 22 May 2020. Acta Acad. Melit. 1800-32, fol. 95.
Laughton, J. K.. "Mends, Sir William Robert (1812–1897)". Oxford Dictionary of National Biography (2004 ed.). Oxford University Press. doi:10.1093/ref:odnb/18559. Accessed 10 October 2010.