The Great Campaigns of the Peloponnesian War saw the use of many unconventional tactics. Besieging Plataea, the Spartans tried to build a mound from which their archers could shoot over the walls. The Platassin tunneled to the mound and removed the dirt from the bottom as fast as the Spartans put it on top. When the Spartans brought up battering rams the Platseans lassoed them and pulled then Inside the walls. At sea, the Spartans drew up 47 ships in a circle, prows outward. Twenty Athenian ships sailed around and around them, forcing them into an ever smaller circle until the Spartan ships were all entangled and easy prey. At Delium the Boeotians, Sparta's allies, used a cauldron of burning coals, a hollowed-out tree and a bellows to make a flamethrower that destroyed the defensive walls.