 In the Battle of Red Cliff in 208 AD, warships were covered with wetted hides as defense against incendiary weapons.By 1130, in the battle of Huangtiandang, Jin sailors built protective bulwarks of an unknown material with oar ports in them, presumably as an adoptive response against its enemies.The introduction of paddle-boats allowed the Song dynasty general Qin Shifu to build two new prototype warships.