HMS Ajax was a 74-gun third rate ship of the line of the Royal Navy, launched on 2 May 1809 at Blackwall Yard.

[1] On 11 September 1810, in a ship action off Elba in the Mediterranean, Charles Benyon, Lieutenant in Ajax, aged 22, was killed attempting to board a French vessel.

[2] On 13 December 350 sailors and 250 marines from the 74-gun third rates Ajax, Cambrian and Kent attacked Palamós.

[4] Apparently Napoleon Bonaparte intended them as a present for Hammuda ibn Ali, the Bey of Tunis.

[5] Admiral Sir Charles Cotton, commander in chief of the British Mediterranean Fleet, decided to buy her and her stores for the Royal Navy.

[1] The conversion process involved removing her copper, ballast and some of the bulkheads, and cutting her down in the shape of a blockship.

In 1858 she resumed guardship duties, this time in Kingstown, now Dún Laoghaire, where she remained until 1864 when she was decommissioned and broken up.