Typical fighting ships in sixteenth century Choson and Japan were little different than their merchant ship counterparts. Fighting ships generally had more oars for greater speed and a better hull design for added maneuverability. Japanese fighting ships still used the boarding tactics employed in the Battle of Lepanto. The captains's main goal was to get close enough to the enemy ship to use grappling hooks and pull his ship close aboard so his soldiers could then engage in hand-to-hand combat with the enemy. When that wasn't possible, archers and men armed with matchlock rifles targeted the crew of the enemy ship and frequently fired flaming arrows to set the enemy ship ablaze. Even the arquebus, a predecessor to the musket used by the Japanese, required the ships to get close enough for the guns to be effective. Well aware of his navy's current limitations, potential threats, and the need to improve and strengthen Choson's naval forces, Admiral Yi Sun-sin began work in 1588 to develop an entirely new ship design.
While diplomatic wrangling continued between Seoul and Kyoto, Admiral Yi was busy creating a genuinely secret weapon, the kobukson, or "turtle ship" (Figure 1). Although Yi Sun-sin is commonly given credit for inventing the "turtle ship," the term kobukson was actually used in historic documents as early as 1414, when King T'aejong first inspected this new warship design. The aggressive use of the kobukson in Koryo's 1419 raid against pirates on Tsushima Island certainly indicates it was originally designed as an attack ship.
Beginning with a hull design adapted for high speed and maneuverability, Admiral Yi's highly-modified kobukson was essentially a flat-bottomed, oar-powered galley 100 feet in length with a 25 foot beam and two large masts rigged with large rectangular sails. Admiral Yi did not have to defend the open seas of the Tsushima Strait, but faced the constant battlefield constraint of inadequate maneuvering room in the narrow channels and shallow waters among the 400 small islands and uninhabited islets of the Hallyo Waterway. This small inland sea stretches 172 km from Hansan Island in the east, including Ch'ungmu, Samch'onp'o and Namhae Island, Odong Island, to the seaport of Yosu in the west.
Japanese superiority in both soldiers and firearms made engaging Japanese ships at close quarters a very dangerous tactic. Admiral Yi could not afford to be boarded, so he designed an arched "roof," believed to have been made of iron plate, that covered ship's entire topside structure to ward off enemy arrows and cannon shells. The top of this roof was studded with sharp upright spikes to deter potential boarders. The Yi court had discussed the idea of building ironclad ships as early as 1413, but the world's first ironclad warship was not actually built until Yi Sun-sin took command of the Choson navy.
Choson had already manufactured some very powerful cannons designed to protect fortresses and they soon figured out how to put them on ships. Yi Sun-sin increased the firepower of his kobukson by mounting thirteen small cannon atop the rowing deck along both flanks of the ship that fired through portholes to allow the vessel to deliver a broadside attack from either side at will. The Choson Navy had four types of cannons; ch'on (heaven), chi (earth), hyon (black) and hwang (yellow). The heavy 660 pound ch'on cannon, with a 5.5 inch bore, could hurl a cannonball only a few hundred yards. Smaller and shorter in range than contemporary English cannons, Admiral Yi's guns certainly proved adequate to counter the threat posed by the smaller cannons aboard Japanese ships.
A large dragon head sat above the reinforced ram in the ship's bow and a wood-fired smoke generator was used to spew sulfur smoke through the dragon's grinning mouth. When put to use with the ship underway, the smoke screen enshrouded the entire ship and no doubt intimidated superstitious enemy sailors. The addition of new advanced cannons, archery ports ahead, astern and abeam, iron spikes on the roof, and the smoke generator in the bow made the kobukson a true offensive weapon.
although the units were not speaking korean.
Somebody knows how can I put the Korean Civilization in the Earth Map that comes with the game? 
