Tar Bomb

Source Pirates of the Inner Sea.

A tar bomb is an easy weapon to make, and devastating in use. A head-sized lump of tar is wrapped around a rope and set on fire. You use the rope to lob the burning tar onto an enemy’s deck, where it sticks and sets the ship alight. In many ways, a tar bomb functions as a less potent version of alchemist’s fire, as it deals less damage and lacks the splash damage of the more expensive substance. Treat this attack as a ranged touch attack with a range increment of 10 feet. Lighting a tar bomb is a move action.

A hit with a tar bomb deals 1d4 points of fire damage and has the potential to set the struck object or creature on fire, causing an additional 1d6 points of fire damage each round unless the target or an adjacent creature makes a DC 15 Reflex save to extinguish the flames as a full-round action. Knocking the tar bomb or the burning creature or object into a body of water or magically extinguishing the flames automatically smothers the fire.