고대 동아시아의 항해술은 ‘시인거리(視認距離) 연안항해(沿岸航海)’-‘천문관측(天文觀測) 대양항해(大洋航海)’ 단계, 조선술은 ‘독목주(獨木舟)’-‘준구조선(準構造船)’-‘구조선(構造船)’ 단계로 발전하였다. 4~5세기까지 한반도와 일본열도에서는 준구조선이 광범위하게 활용되었고, 신라와 일본의 자료에서는 7세기 무렵부터 구조선의 존재가 확인된다. 이와 달리, 중국에서는 늦어도 위진남북조 시대에 대규모 구조선이 활용되었으며, ‘천문관측 대양항해’ 단계의 항해술도 확인된다.
동아시아 속에서 백제 한성기 해양기술의 시간적, 공간적 위치는 위진남북조시대에 천문관측 대양항해, 구조선을 널리 활용한 중국과 7세기 이후 구조선 자료가 확인되는 신라, 일본 사이에 존재한다. 백제와 중국의 교섭기록에서는 구조선 활용 흔적을 찾을 수 있다. 백제는 4세기초에 낙랑·대방지역 유민을 통해 해양 경험, 기술, 정보를 습득하여, 4세기 후반에 동진과 빈번하게 교섭, 교류하였을 것으로 추정된다. 중국과 빈번한 해양 교섭 및 교류는 백제 해양기술의성장으로 이어졌을 것이다. 아울러, ‘시인거리 연안항해’에서 필요한 장거리 연안의 정보 습득, 안전한 기항지 확보를 위하여, 백제는 마한을 세력권이나 영역에 포함하고, 가야의 여러 세력과 우호관계를 맺으면서 연안항로를 네트워크 형태로 운용하였다.
백제는 한성기에 황해중부횡단항로를 건너는데 필요한 천문관측 대양항해, 구조선의 해양기술을 중국으로부터 수용하였을 가능성이 충분히 있다. 왜까지 이어지는 서남해안 연안항로네트워크에서는 준구조선을 주로 활용하였으나, 백제 한성기의 구조선 활용 가능성, 중국 선박의 왕래 가능성, 백제와 왜 교섭기사에 남은 구조선의 흔적 등을 종합해보면, 서남해안 연안항로 네트워크에서 구조선이 활용되었을 개연성은 있다.
한성기 백제는 중국으로부터 보편적인 동아시아의 해양기술, 즉 천문관측 대양항해, 구조선단계의 항해술과 조선술을 수용·활용하였던 것으로 생각되며, 더 나아가 이러한 기술을 신라와일본에 전파하는 징검다리 역할을 하였다.
The maritime technology of ancient East Asia evolved from the stage of coastal navigation within visible distance of land to that of long-distance oceanic navigation based on astronomical observation, while shipbuilding progressed through the stages of dugout canoes, semi-structured vessels, and fully structured vessels. Semi-structured vessels began to be widely used by the inhabitants of the Korean Peninsula and the Japanese Archipelago in the fourth and fifth centuries, while fully structured vessels appeared around the seventh century according to archaeological evidence from Silla and Japan dating from the same period. In China, fully structured vessels came to be widely used during the Wei, Jin, and Northern and Southern Dynasties at the latest. It was also during that period that Chinese seafarers began to navigate the oceans using astronomical observation.
The temporal and spatial position of the maritime technology used by Baekje in the Hanseong period is located somewhere between China in the period of the Northern and Southern Dynasties, where oceanic navigation by astronomical observation was common, together with the use of fully structured vessels, and Silla and Japan in the seventh century when fully structured vessels first began to be used. Early records of diplomatic relations between Baekje and China suggest that Baekje had already begun to use fully structured vessels in this period. It is conjectured that Baekje obtained advanced maritime knowledge, skills and experience in the early fourth century through migrants who came from Nangnang and Daebang and, by the second half of that century, through the frequent exchanges between Baekje traders and diplomats and Eastern Jin. Frequent exchanges with China via sea routes must have played a crucial role in the development of maritime technology in Baekje. Baekje also increased its knowledge of long-distance navigation through repeated visible-distance coastal voyages to the neighboring chiefdoms of Mahan and Gaya and its efforts to secure safe ports in those areas. Baekje maintained friendly relations with these chiefdoms, developing a coastal navigation network around the region.
It is highly possible that, in the Hanseong period, Baekje acquired from China the knowledge and skills it required to construct fully structured vessels and navigate the oceans based on astronomical observation, thus ensuring safe passage across the Yellow Sea to and from China. The major means used by Baekje to link the ports along the southwestern coast of the Korean Peninsula and the Japanese northwestern coastline must have been semi-structured vessels. Considering the possibility that Baekje used fully structured vessels in the Hanseong period, and that Chinese traders visited Baekje, and given the evidence of the use of fully structured ships in Baekje's exchanges with the Japanese state of Wa, one should not exclude the possibility that fully structured vessels followed the network of sea routes off the southwest coast of the Korean Peninsula.
In conclusion, it is highly possible that Hanseong Baekje was first able to acquire the advanced navigation and shipbuilding skills and knowledge developed in China, such as oceanic navigation based on astronomical observation and fully structured ships, and then transmitted such skills and knowledge to Silla and Japan.