In ancient China, the sluice gate, the canal lock, and flash lock had been known since at least the 1st century BCE (as sources then alluded that they were not new innovations), during the ancient Han dynasty (202 BCE-220 CE) [REF].
Although the drydock had been known in Ptolemaic Egypt since the late 3rd century BCE (by a Phoenician; not used again until Henry VII of England in 1495), the scientist and statesman Shen Kuo wrote of its use in China to repair boats during the 11th century.