To prevent the further introduction of succours by sea, the crusaders endeavoured to take possession of the tower of Flies, a strong castle, built upon a rock in the midst of the sea at the mouth of the harbour, which commanded the port. The Templars employed one of their galleys upon this service, and crowds of small boats, filled with armed men, military engines, and scaling-ladders, were brought against the little fortress, but without effect. The boats and vessels were set on fire by the besieged and reduced to ashes, and after losing all their men, the Christians gave over the attempt. On the land side, the combats and skirmishes continued to be incessant. Wooden towers, and vast military machines, and engines, were constantly erected by the besiegers, and as constantly destroyed by the sallies and skilful contrivances of the besieged. The Templars, on one occasion, constructed two battering machines of a new invention, and most enormous size, and began therewith furiously to batter the walls of the town, but the garrison soon destroyed them with fire-darts, and beams of timber, pointed with red-hot iron.[85] At the commencement of the next year, (587, Hejir. which began Jan. 29th, A. D. 1191,) a tremendous tempest scattered the fleet of the crusaders, and compelled their ships to take refuge in Tyre. The sea being open, Saladin hastily collected some vessels at Caiphas, threw a fresh body of troops into Acre, and withdrew the exhausted garrison, which had already sustained so many hardships and fatigues in defence of the town. This exchange of the garrison was most happily timed, for almost immediately after it had been effected, the walls of the city were breached, and preparations were made for an assault. The newly-arrived troops, however, repulsed the assailants, repaired the walls, and once more placed the city in a good posture of defence. The scarcity and famine in the christian camp continued to increase, and a vast many of the crusaders, utterly unable to withstand the hardships and difficulties of their position, deserted to Saladin, embraced the Mohammedan faith, and were employed by him, at their own request, in cruising off the coast against their quondam friends. Bohadin tells us that they met with vast success in their employment. On board one of their prizes was found a silver table, and a great deal of money and plate, which the captors brought to the sultan, the 13th Dhu’lhajja, but Saladin returned the treasure to them, saying, that it was a sufficient satisfaction to him and the Moslems, to see that the Franks pillaged and plundered one another with such alacrity.