Suddenly there was a jar that stirred all on board off their feet. There was a sensation of sinking. As previously instructed, the diving rudder man immediately gave the submarine up-rudder. Captain Nicholson ordered full speed ahead, although he knew it would mean that the vessel's periscope would show, giving the enemy a good look at the vessel. "If we hadn't come up," said Captain Nicholson, "we would have been sucked down solidly into the sand, and good-bye to our chances at those men-o-war inside." He was silent a moment and then added: "This is what I call tough luck. We shall have to porpoise." In a second the submarine was again down in the deep basin beyond the bar. The vessel hadn't been up long enough for the commander even to get a look around. "Here's where we get busy," said Captain Nicholson. "It's up to us to rush the work along before the men in the fort, who must have seen us, can take measures against us." The submarine ran along at a speed of ten knots at a depth of forty feet and in almost no time at all had covered the mile from the entrance to where the men-of-war lay. "Now's the time," said Commander Nicholson. Quickly the torpedoes, 18-inch superheaters, were placed in the tubes. It only remained to arise, sight the enemy and fire. Quickly the little vessel rose until her periscope gave the commander a view of the first Turkish cruiser. The commander gave the word for a quick rise and the submersion, and took a firm grip on the periscope. Through the spray that broke, the keen eyes of the commander made out the form of his first target. There, on the port side of the submarine, was a large Turkish cruiser, stern to. Midstream, to starboard, lay a light cruiser of the first class, and 800 yards up the basin, between the two, a small armored cruiser. The flat country was thickly veiled with mist and a drizzling rain. A choppy sea added to the chances of making the first attack on the Turks unobserved. Captain Nicholson steered a course straight to the starboard side of the first Turkish cruiser, to launch the torpedo just forward of amidships at a distance of about 300 yards. The lookout on the cruiser had not picked up the submarine. Captain Nicholson saw an officer at the stern, sighting the fort with his glass. The Y-3 crept on unnoticed. Suddenly a seaman on the forecastle of the cruiser made out the periscope of the submarine, waved his cap frantically and ran toward an officer. All this, as it progressed, Captain Nicholson repeated to the lads, who stood just behind him. Jack glanced at the range scale. It read 349 yards. The cross wires of the periscope were on her middle funnel. Captain Nicholson jerked the firing valve for No. 1 torpedo. There was a hiss of air and a rush of water. The first torpedo had been launched! CHAPTER XXV A SUCCESSFUL RAID