HMS Diadem (1782)

HMS Diadem was a 64-gun third rate ship of the line of the Royal Navy, launched on 19 December 1782 at Chatham. She participated in the Battle of Cape St Vincent in 1797 under Captain George Henry Towry.

In 1798 she was converted to serve as a troopship. On 7 April 1799 she left Portsmouth together with Trompe. They were carry the West York militia to Dublin.

In 1800 under the command of Post Captain Sir Thomas Livingstone she was employed in the expedition to Quiberon and Belle Île under Sir Edward Pellew, subsequently she was employed in the expedition to Cádiz under Admiral Lord Keith.

Because Diadem served in the navy's Egyptian campaign between 8 March 1801 and 2 September, her officers and crew qualified for the clasp "Egypt" to the Naval General Service Medal that the Admiralty authorised in 1850 to all surviving claimants.

Between April and July 1810 Diadem was at Chatham being fitted for service as a troopship of 28 guns. In June Captain John Phillimore (or Philmore) commissioned her for Lisbon. She then spent some time working with the Spanish anti-French forces on the north coast of Spain. In January 1812 she carried released Danish prisoners of war from Plymouth to Chatham. Later, she sailed to the Halifax station. Phillimore transferred to command of HMS Eurotas on 4 May 1813.