Watertight Compartment

A watertight compartment is a section of a ship's hull sealed off from the rest of the vessel by solid internal walls, called bulkheads, so that if the hull is breached in one compartment, water flooding in stays contained there instead of spreading through the whole ship and threatening to sink it. The technique originated in China, where the Song dynasty author Zhu Yu recorded in a book written in 1119 that Chinese ship hulls were already built with bulkhead construction, and archaeological confirmation survives in a Song dynasty ship recovered from China's southern coast in 1973, a vessel roughly 24 meters long whose hull was divided into twelve separately walled, watertight compartments and dated to about 1277; an even earlier fifth-century text, the Garden of Strange Things by Liu Jingshu, already describes a ship able to take on water at the bottom without sinking, showing the underlying principle was understood centuries before that. European shipbuilders were slow to adopt the practice: Benjamin Franklin urged building ships in what he called the Chinese manner, with caulked, subdivided holds, as early as 1787, but watertight bulkheads did not become standard in Western shipbuilding until the early nineteenth century.