Alexander, finding that his efforts were impeded very much by the ships of the Tyrians, determined on collecting and equipping a fleet of his own. This he did at Sidon, which was a town a short distance north of Tyre. He embarked on board this fleet himself, and came down with it into the Tyrian seas. With this fleet he had various success. He chained many of the ships together, two and two, at a little distance apart, covering the inclosed space with a platform, on which the soldiers could stand to fight. The men also erected engines on these platforms to attack the city. These engines were of various kinds. There was what they called the battering ram, which was a long and very heavy beam of wood, headed with iron or brass. This beam was suspended by a chain in the middle, so that it could be swung back and forth by the soldiers, its head striking against the wall each time, by which means the wall would sometimes be soon battered down. They had also machines for throwing great stones, or beams of wood, by means of the elastic force of strong bars of wood, or of steel, or that of twisted ropes. The part of the machine upon which the stone was placed would be drawn back by the united strength of many of the soldiers, and then, as it recovered itself when released, the stone would be thrown off into the air with prodigious velocity and force.