The purpose of this study is not to imagine and reproduce Lee Sun-shin’s turtle ship at the time of the Imjin War (Japanese invasions of Korea in 1592), but to estimate the internal structure of the late Joseon turtle ships that were actually used in the late 18th century (Late Joseon Dynasty) based on historical records related to the Joseon Navy at that time. Like the infantry (foot soldiers), the Joseon Navy had matchlock soldiers as its main force, and the number of artillerymen was less than that of archers. More specifically, as a result of examining the historical materials, it was confirmed that the proportion of artillery among the crew of the turtle ship in the late Joseon period was very small. Since the Imjin War, the turtle ship has not only increased in size, but its main weapon was changed from conventional cannons to a matchlock. The most important issue raised in this study is that the so-called “Korean-style Oar” paradigm, which all preceding researchers have agreed to, is merely a weak argument that cannot be confirmed in historical records. In the West, only the oar was used, but in the East, oar, Yuloh, and Ro were used altogether. So, for large warships, it makes sense to infer oars were used for rowing rather than Chinese Yuloh and Japanese Ro. If we reconsider the oar rowing method in this way, it is possible to reasonably solve the problem of the coexistence of rowers and soldiers inside the turtle ship, which has been debated for a long time.