Turtle ship

A turtle ship (Korean: 거북선; RR: geobukseon; Korean pronunciation: [kʌbuksən]) was a type of warship that was used by the Korean Joseon Navy from the early 15th century up until the 19th century. They were used alongside the panokseon warships in the fight against invading Japanese fleets. The ship's name derives from its covering that was said to resemble a turtle shell. Some historians have described it as a very early type of ironclad though the historical evidence for this is uncertain.