Endymion - class frigate The " Endymion " - class was a class of six Royal Navy 40 - gun fifth - rate frigates , with the prototype launched in 1797 and five slightly amended versions built of fir launched from 1813 to 1814 . Design . In 1794 , a frigate squadron under the command of Captain Sir John Borlase Warren captured the French 40 - gun frigate . Surprisingly to her captors , the ship was armed with 26 × 24 - pounder long guns , a main armament that was relatively uncommon for frigates in the 18th century . Furthermore , the " Pomone " impressed the British with outstanding sailing qualities in every variation of the wind , and being capable of sailing more than 13 knots . On 30 April 1795 , the Admiralty ordered three frigates — with 36 guns , 38 guns and 40 guns — the first and third built to the lines of the captured French frigate and the second to a new design by the Surveyors ( the ship designers of the Royal Navy ) . The 40 - gun French design was copied from the " Pomone " , and in November 1795 the keel was laid down at the Rotherhithe shipyard of John Randall & Company for the new ship , which on 14 November 1795 was named as the . She was launched on 29 March 1797 and towed to Deptford Dockyard , where she was commissioned in April 1797 and completed on 12 June 1797 . The " Endymion " was not an exact copy of the " Pomone " , being built to British design standards with stronger construction . Surprisingly , " Endymion " sailed even better than " Pomone " , reaching 14 . 4 knots , the highest recorded speed during the Age of Sail . Reclassified as a 48 - gun fourth - rate frigate in February 1817 , then as 50 - gun , and finally as 44 - gun in February 1839 , " Endymion " ' s fine qualities were such that she continued to be praised for nearly half a century . She was finally broken up at Plymouth Dockyard in June 1868 . The 1812 Programme . Early in 1812 , war with the United States seemed inevitable . To cope with the heavy American 24 - pounder frigates of the " Constitution " - type , the Admiralty decided to build a batch of new 24 - pounder frigates . During the long war with France , the standard British frigate was of about 1000 tons and armed with a main battery of only 18 - pounders , no match for the big US ships . The only proven design for a suitable 24 - pounder frigate was that of " Endymion " , and in May 1812 two ships were ordered from Wigram , Wells & Green of Blackwall Yard , who were to construct all five ships eventually built . They differed from the prototype by being constructed of " fir " ( actually , pitch pine ) rather than oak , and mounted an extra ( fourteenth ) pair of 24 - pounder guns on the upper deck forward . All would be reclassified as 50 - gun fourth - rate frigates in February 1817 ; however , the use of softwood in their construction was such that they were only intended for a short lifetime , and indeed all five were taken to pieces after a few years ' service . The first pair were originally ordered on 4 May 1812 as the " Tagus " and " Eridanus " of the 18 - pounder armed " Leda " class , but were renamed on 7 January 1813 as the and the . The War broke out in June , and on 26 December two further ships were ordered , becoming the and . The final ship was the , ordered on 7 January 1813 . These five new ships were of a slightly modified design , having ports for 28 instead of 26 × 24 - pounders and were built of softwood , to speed up the construction . The ships were launched from June 1813 to February 1814 . Principal characteristics . There were small variations in the dimensions of the different ships :