Following the path of the powder-incense until the cannon fires

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For naval warfare, use the "hull-striking" cast-iron cannon original: 鐵鑄大砲 (tiezhu dapao). It is one foot five inches long and four inches in diameter. Inside, it contains two catties original: 斤 (jin); a unit of weight approximately 600g of propellant powder. The fuse original: 藥信 (yaoxin); literally "powder message" is coiled around the top of the cannon. It fires a large lead ball weighing two catties. Seal the mouth of the cannon with yellow wax. Use a single piece of dog skin sewn into a bag to wrap the cannon in the center This serves as a primitive waterproofing method for underwater use. Use four spikes original: 錐 (zhui); literally "awls" or "drills" to nail it to the bottom of the enemy ship. Use eight cannons for every ship's hull. When the burning incense [fuse] reaches the powder, the cannon fires. The bottom of the ship is shattered to pieces, causing the vessel to sink, so the enemy may be captured alive.

Formula for the Fuse original: 藥信方 (Yaoxin fang)