A report reconstructing the internal structure and operational methods of the turtle ship, a key strategic asset of the Joseon navy during the Imjin War (Japanese invasions of 1592-1598), is drawing attention.
The National Research Institute of Maritime Heritage Studies recently published a report analyzing the structure, functions, and operational systems of the two turtle ships recorded in the "Complete Works of Admiral Yi Sun-sin," following about five years of research and investigation. The Complete Works of Admiral Yi Sun-sin was published in 1795, during the reign of King Jeongjo (1776-1800), about 200 years after the Imjin War ended. Through its "Academic Restoration Report on the Turtle Ship," the institute stated that "both the Tongjeyeong turtle ship and the Jeolla Left Naval Command turtle ship in the 'Complete Works of Admiral Yi Sun-sin' had a two-story structure."
The Tongjeyeong was the highest naval command organization that supervised the navies of the three provinces of Gyeongsang, Jeolla, and Chungcheong during the Joseon Dynasty, while the Jeolla Left Naval Command was the organization responsible for naval command and defense of the coastal waters of Jeolla Left Province. The institute estimated that "the two turtle ships weighed about 140.4 tons each, and were large warships measuring 35.27 meters in total length including the tail (113 cheok, applying 31.22 centimeters per cheok)." Regarding the internal space, it concluded there was a "two-story structure," explaining that "the first floor was for weapon storage and soldiers' rest, while the second floor consisted of a combat space for rowing and firing cannons and a loft-style upper deck plate (sangpopan)."
Regarding the upper deck plate, the institute's assessment is that the two turtle ships used it for different purposes. The institute said, "It has been confirmed that the Tongjeyeong turtle ship used it as a space for operating sails, while the Jeolla Left Naval Command turtle ship used it as a space for observing the exterior," and attached an illustration depicting this.
How did the sailors row the turtle ships at sea? The institute gave weight to the possibility that they rowed while seated, saying, "Considering the enormous size of the turtle ship and its enclosed nature during combat, the method of rowing while standing would have had significant structural constraints." This conclusion also took into account a painting depicting the "Jeongsagiseon," a Joseon envoy ship anchored at Osaka Port in Japan in 1763, and the case of the Daedonggang hwanmokseon, in which oars arranged in a front-to-back seating configuration were confirmed.
In the report, the institute also dealt in detail with the structure and differences of the two turtle ships. The two turtle ships recorded in the "Complete Works of Admiral Yi Sun-sin" differ in the number of oars, the shape of the dragon head, and other features. The institute explained that "the Tongjeyeong turtle ship had a structure that could be used for both ceremonial and combat purposes, as it was rigged with sails that could be quickly switched by lowering or raising the mast." By contrast, the Jeolla Left Naval Command turtle ship had no mast and was structured around oars. The institute said, "We also learned that the structures on both sides of the roof plate (gaepan), previously presumed to be entrances, were 'observation posts' for external observation and combat command." This research was led by curatorial researcher Hong Soon-jae, who has studied underwater archaeology and traditional ships for more than 30 years and has restored and reproduced various old ships including the Joseon envoy ship.
Based on the research results, the institute also produced a turtle ship model scaled down to one-thirtieth of the original size. The model is scheduled to be introduced at the "Republic of Korea Pavilion," which promotes Korean heritage, in conjunction with the 48th UNESCO World Heritage Committee (July 19-29) held this month at BEXCO in Busan.
