“The stern-post rudder [was a] steering device mounted on the outside or rear of the hull. [It] could be lowered or raised according to the depth of the water. This type of rudder made it possible to steer through crowded harbors, narrow channels, and river rapids.” — from The Beijing Qingming Scroll and Its Significance for the Study of Chinese History, by Valerie Hansen

Shipbuilding

The Song Chinese were world leaders in shipbuilding. Watertight bulkheads improved buoyancy and protected cargo. Stern-mounted or stern-post rudders (see right) improved steering. Sounding lines were used to determine depth. Some ships were powered by both oars and sails and large enough to hold several hundred men.

The Compass

Also important to oceangoing travel was the perfection of the compass. The way a magnetic needle would point north-south had been known for some time, but in Song times the needle was reduced in size and attached to a fixed stem (rather than floating in water). In some cases it was put in a small protective case with a glass top, making it suitable for sea travel. The first reports of a compass used in this way date to 1119.

Chinese mariner’s compass, mid 19th century © Science Museum/Science & Society Picture Library, London

More about Shipbuilding during the Song Dynasty

• Watery Kingdom: China’s Mariners from Antiquity to the Ming Dynasty [Vancouver Maritime Museum]
With text detailing advances in shipbuilding during the Song Dynasty and the significant 1974 excavation of a Song-dynasty ship near Quanzhou.

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