HMS Fortitude was a 74-gun third-rate ship of the line of the Royal Navy, built by John Randall & Co. and launched on 23 March 1780 at Rotherhithe. Under Captain Richard Bickerton, Fortitude served in the English Channel. In April 1781 she participated in the second relief of Gibraltar. In May 1781, during the Fourth Anglo–Dutch War, Vice-Admiral Hyde Parker's shifted his flag from HMS Victory to Fortitude. On 5 August, Fortitude fought in the Battle of Dogger Bank as Parker's flagship. After a desperate, bloody battle in which neither combatant gained any advantage, both sides drew off.