French ironclad Thétis The French ironclad " Thétis " was a wooden - hulled armored corvette built for the French Navy in the late 1860s . She was named for the Greek sea - goddess Thetis . During the Franco - Prussian War she was assigned to a squadron of French ships that attempted to blockade the Prussia n ports in the Baltic Sea in 1870 . She accidentally rammed her sister in 1877 . En route to the Pacific in 1884 her propeller fell off and she had to return to France under sail . " Thétis " was eventually hulked in New Caledonia . Design and description . The s were designed as improved versions of the armored corvette suitable for foreign deployments . Unlike their predecessor the " Alma " - class ships were true central battery ironclads as they were fitted with armored transverse bulkheads . Like most ironclads of their era they were equipped with a metal - reinforced ram . " Thétis " measured between perpendiculars , with a beam of . She had a mean draft of and displaced . Her crew numbered 316 officers and men . Propulsion . The ship had a single horizontal return connecting - rod steam engine driving a single propeller . Her engine was powered by four oval boilers . On sea trials the engine produced and the ship reached . Unlike all of her sisters except , she had two funnels , mounted side - by - side . " Thétis " carried of coal which allowed the ship to steam for at a speed of . She was barque - rigged and had a sail area of . Armament . " Thétis " mounted her four Modèle 1864 breech - loading guns in the central battery on the battery deck . The other two 194 - millimeter guns were mounted in barbettes on the upper deck , sponsoned out over the sides of the ship . The four guns were also mounted on the upper deck . She may have exchanged her Mle 1864 guns for Mle 1870 guns . The armor - piercing shell of the 20 - caliber Mle 1870 gun weighed while the gun itself weighed . The gun fired its shell at a muzzle velocity of and was credited with the ability to penetrate a nominal of wrought iron armour at the muzzle . The guns could fire both solid shot and explosive shells . Armor . " Thétis " had a complete wrought iron waterline belt , approximately high . The sides of the battery itself were armored with of wrought iron and the ends of the battery were closed by bulkheads of the same thickness . The barbette armor was thick , backed by of wood . The unarmored portions of her sides were protected by iron plates . Service . " Thétis " , named for the Greek sea - goddess Thetis , was laid down at Toulon in 1865 and launched on 22 August 1867 . The ship began her sea trials on 1 May 1868 and was put into reserve at Brest the following year . She was commissioned on 20 July 1870 for the Franco - Prussian War and assigned to the Northern Squadron . On 24 July 1870 she departed Cherbourg in company with the rest of the Northern Squadron and they cruised off the Danish port of Frederikshavn between 28 July and 2 August until they entered the Baltic Sea . The squadron , now renamed the Baltic Squadron , remained in the Baltic , attempting to blockade Prussian ports on the Baltic until ordered to return to Cherbourg on 16 September . The ship was assigned to the Evolutionary Squadron in 1871 and detached to the Levant Squadron the following year . During the Cantonal Revolution " Thétis " and her sister spent much of September – October 1873 in the port of Cartagena , Spain where they could protect French citizens . She became the temporary flagship of Vice Admiral Roze after 31 October 1875 when the armored frigate caught fire and exploded in Toulon . " Thétis " was paid off on 1 March 1876 , but was recommissioned on 18 April 1877 for service with the Evolutionary Squadron . On 3 July 1877 she accidentally rammed " Reine Blanche " who had to be run ashore to prevent her from sinking . The ship was in reserve between 1878 and 1881 although she was intended to be used as the flagship of the Pacific Squadron . Her sister was sent instead . On 8 October 1885 she was commissioned as the flagship of Rear Admiral Marcq de St . Hilaire and sailed for the Pacific . " Thétis " lost her propeller off Madeira and had to return to Cherbourg under sail where the admiral transferred his flag to the . She ended her days as a hulk in Nouméa , New Caledonia .