The Song navy possessed a number of paddle-wheel boats known as "Flying Tiger Warships". These vessels may have been inspired by the waterwheels that were commonly employed to irrigate fields, but who knows? They were propelled by manpower, each boat having eight wheels powered by forty-two men on treadmills. The wheels and treadmills themselves were covered by an enormous housing structure, so the ships appeared to move "like a dragon" without any effort on the part of the sailors aboard. Terrified onlookers were convinced that supernatural forces had been harnassed to power the ships. On the top deck, archers were stationed and the boat was equipped with an enormous battering ram-like structure that was designed to be dropped so that it crashed down onto the deck of enemy ships should they come close enough.

The 12th Century, most of which falls into the Ten Kingdoms Period, was a time of strife for China. The Tang Dynasty had fallen and, though the Song had arisen in 906 to take their place, they had been unsuccessful in pushing back nomadic invaders from the north. By 1127 they had fallen back below the Yangtze River, making Lin'an (Hangzhou) their capital. In the north, the Mongols, the Western Xia, and the Jin continued to struggle for dominance. Then, in 1161, the northern Jin empire overran the Liao and turned their attention to the Song in the south. Attacking on three fronts, they sent cavalry forces from western Sichuan province; a second force of troops to cross the Yangtze near Nanjing; and attempted to seize Hangzhou with a fleet of six hundred warships and 70,000 men.

After successfully repulsing the cavalry attack, the Song emperor sent Yu Yunwen with a fleet that included 24 Flying Tiger warships to meet the forces at the Yangtze. The Jin soldiers, having never before seen these craft that "seemed to move without sails or oars", were terrified. Then, from the paddle wheelers, the Song launched gunpowder bombs from catapults onto the decks of the Jin ships. This incident, it is believed, was the first time gunpowder was ever used in battle. The bombs were made of earthenware or paper pots packed with gunpowder, lime, and broken bits of metal. When set alight, they exploded upon impact with a ship's deck or with the water, "making a noise like thunder." The lime scattered into a smoky fog, blinding and terrifying the enemy men and horses. I'm sure the bits of metal acted like modern-day claymores, killing more than a few of the enemy. The Song forces were then easily able to board the ships and defeat the invaders.

Then on November 16, the Song navy went out to meet the Jin's main fleet off the coast of the Shandong Peninsula. Though vastly outnumbered (the Song only had 20 warships and three thousand men), they found the Jin armada stretched out along the coast in a long line. Using their gunpowder weapons, they were able to pick off the ships one at a time.

Sources:

Brown, Roxanne, and Sten Sjostrand. Maritime Asia. 12 Sept. 2004
http://www.maritimeasia.ws/topic/chronology.html

Chung, Yoon-Ngan. Yue Fei the Hakka General. 18 Apr. 1997
http://www.asiawind.com/pub/forum/fhakka/mhonarc/msg00235.html

Levathes, Louise. When China Ruled the Seas: The Treasure Fleet of the Dragon Throne, 1405-1433. New York: Oxford UP, 1994. 44-47.