Behind the Myth: The Turtle Ship

DID KOREANS REALLY INVENT THE FIRST SHIP WITH IRON ARMOR?

The question should be asked with sensitivity, because there is some national pride at risk in the answer. In particular, South Jeolla Province and its port town of Yeosu have long celebrated their status as the home of the geobukseon, or “turtle ship” – a warship supposedly protected from Japanese projectiles and boarding parties by an iron roof covered in spikes, said to be the first historical use of iron armor in naval warfare.

The turtle ship’s role in Korea’s national mythology is even more important than its role in world history. The ship gets a lot of attention in Korean retellings of the Imjin War, an invasion by Japan in 1592, which now symbolizes every war. Its creation and use suggests that Korea can compensate for its small size through ingenuity.

Nevertheless, evidence strongly supports the theory that the turtle ships designed in 1592 had only wooden roofs with iron spikes. In his book Haeng Rok, Yi Bun – nephew to the famous Admiral Yi Sun-shin – described the vessels in detail, explaining that “the turtle’s ‘back’ is a roof made with planks.” The prime minister of Korea at that time, Yu Song-nyong, also reported that the ships were “covered by wooden planks on top.”

Contradictory evidence is almost nonexistent. Scholars find no mention of plated ships in any Korean writing from the era. Even Admiral Yi Sun-sin, who ordered the construction of the ships, wrote nothing of the idea in his journal, possibly because he realized that putting iron decks on the ships would have been a bad idea. The ships did not need the additional armor; thick wood was enough protection, since the Japanese used few cannons at sea. Moreover, cladding the ships in iron would have slowed them down. Since turtle ships were meant to ram other vessels, their speed was very important. Finally, there was the expense: the amount of iron necessary to armor a single gobukseon equaled the amount of iron needed for an entire second gobukseon.

But even if the vessel’s architect, Na Dae-yong, did not cover his creations with metal, he still designed a ship worthy of Korean pride. The gobukseon represented a multitude of advancements in shipbuilding. Ironically, one of these advances was the use of wooden nails instead of metal ones. Metal nails rusted, weakening the ship, but the wooden nails absorbed water and expanded in their holes, which strengthened the ships’ joints. More visibly, the ships became capable of shooting cannonballs directly ahead and behind themselves, a new trick the sailors used to brutal advantage; they rammed enemy ships, then fired cannonballs at them at nearly point-blank range.

For now, however, an iron roof remains the mistaken focus of praise for the turtle ship.