Why ancient China did not use steel to build ships

Ancient Chinese shipbuilding with many types of wood, generally are locally sourced, the best of the best. And according to the different characteristics and properties of wood used in different parts of the ship.

Shipbuilding wood generally use pine or cedar. Ship side and bottom with two or three planks, and with tung oil, lime cabin seam, can prevent water leakage. Each boat is generally separated into more than ten compartments, even if one or two compartments leakage, but also does not lead to the sinking of the ship.