Louchuan

'tower ships') were a type of Chinese naval vessels, primarily a floating fortress, which have seen use since the Han dynasty.

There are ports and openings for crossbows and lances [and at the sides there is provided felt leather to protect against fire], while (on the topmost deck) there are trebuchets for hurling stones, set up (in appropriate places).

In the Jin period the Prancing-Dragon Admiral, Wang Jun, invading Wu, built a great ship 200 paces (1000 ft.) in length, and on it set flying rafters and hanging galleries on which chariots and horses could go.

But if [all of a sudden] a violent wind is encountered, (such ships are likely to) get out of human control, so they were judged inconvenient in practice [for warlike action].

[1]The use of such ships in riverine warfare, especially along the Yangtze River, stretches back to the late Han dynasty, and perhaps even earlier.