Louchuan

Louchuan (楼船, lit. tower ships) were a type of naval vessel, primarily a floating fortress, which has seen use in China since the Han Dynasty. Meant to be a central vessel in the fleet, the louchuan was equipped for boarding and attacking enemy vessels, as well as with siege weapons including traction trebuchets for ranged combat.

Description
Historical records relating to the lou chuan are found in sources such as the Wujing Zongyao, written during the Song Dynasty, and the Taibai Yinjing from the Tang Dynasty. From the latter (as translated by Joseph Needham), the tower ships were described as:

The use of such ships in riverine warfare, especially along the Chang Jiang, stretches back to the late Han Dynasty, and perhaps even earlier.