Alma-class ironclad
 The Alma-class ironclads were a group of seven wooden-hulled armored corvettes built for the French Navy in the mid to late 1860s. Three of the ships attempted to blockade Prussian ports in the Baltic Sea in 1870 during the Franco-Prussian War. Three others patrolled the North Sea and the Atlantic while the last ship was en route to Japan when the war began and blockaded two small Prussian ships in a Japanese harbor.