By that time Congress was beginning to wake up to the necessity for a more vigorous policy with regard to the Barbary powers, and the squadron was directed to protect American shipping by force. The corsairs interpreted this to mean war, and their aggressions reached such a pitch, after the return of Dale's squadron in 1802, that in 1803 Commodore Preble was sent out with the Constitution, the Philadelphia, and five smaller vessels, to reduce these piratical powers. Bainbridge was promoted from the command of the Essex to the Philadelphia, a fine thirty-eight-gun frigate, carrying a few more than three hundred men. Her first lieutenant was David Porter, who, as a young midshipman, had distinguished himself in the Constellation under Captain Truxtun, and who was destined to a highly honorable and active career during the whole time of his service in the navy. The Philadelphia arrived at Gibraltar in August, 1803, and the next day began to cruise up and down the straits in search of corsairs. In a day or two she fell in with a Moorish vessel, the Meshboha, in company with an American brig which had been captured, and her company taken aboard the Meshboha. The Philadelphia stood by, and forced the Moorish captain, Lubarez, to send all his prisoners to the Philadelphia, and to come aboard himself. Bainbridge invited him into the cabin, and feeling sure that he had orders to capture American ships, directed him to produce these orders. Lubarez stoutly denied he had any such orders. "Very well," coolly responded Bainbridge, taking out his watch. "I am now going on deck for half an hour. When I return, if you cannot show your orders, I will immediately hang you at the yardarm for a pirate." At the end of half an hour Bainbridge returned. Lubarez then sullenly admitted he had orders, but they were inside his waistcoat. "Take off your waistcoat," said Bainbridge. Lubarez began slowly to remove his waistcoat; but another appeared under it. He finally peeled off five waistcoats, and underneath the last one were the orders. Bainbridge immediately took possession of the Meshboha and her prize, and carried them both into Gibraltar. In a few days Commodore Preble reached Gibraltar, and Bainbridge was sent to Tripoli, with orders to intercept and capture every Tripolitan vessel possible. He arrived before Tripoli, in the autumn of 1803, and immediately began a vigorous blockade. On the 31st of October he gave chase to a xebec trying to get into the harbor. He was rapidly overhauling her, when, at the mouth of the harbor, the water suddenly shoaled, and the Philadelphia ran upon a tremendous reef, known to the Tripolitans, but not down on any chart.