Turtle ships
A Geobukseon, also known as turtle ship in western descriptions, was a type of large Korean warship that was used intermittently by the Royal Korean Navy during the Joseon dynasty from the early 15th century up until the 19th century.
Built: circa 1590
Armament: sulfur gas thrower, iron spikes, 26 cannons
Length: 100 to 120 feet (30.5 to 36.6 m)
Completed: 20-40 units deployed
Laid down: March 12, 1592
Builders: Yi Sun-shin