Reference material containing official documents submitted to withamyeong and Tongyeong by Yi Eon-sub (李彦燮, 1692–?)

while serving as Naval Commander of the left Gyeongsang-do Province from July 1747 (Yeongjo year 23) to September 1748,

as well as reports he submitted to King Yeongjo and Prince Sado.

One phrase that stands out in the report is “a request to build an armored warship (geobukseon) in which combatants can fight while hidden inside the essel

and that can change direction quickly and easily, rather than using a ‘tower ship’ (nuseon, 樓船) [a kind of flating fortress called lou chuan in Chinese],

which has a loft, is slow, and is prone to flipping while mooed.”

Besides this, one can also learn how he comprehended and solved various problems that took place in the jurisdiction of the naval bases of left Gyeongsang-do Province,

such as missing a Japanese vessel that was drifting near Cheonseongjin (天城鎭, current Gadeokdo Island Busan).

Since many of the records written here are absent from the government compiled historical records,

this document has n important value as a historiography in understanding the contemporary circumstances.