By now he could feel his heart pounding fiercely while a fitful darkness obscured his sight. Well he knew these symptoms--he had stayed down longer than he should have. But with his signal for a lift he felt the cables tighten and then he was swept along through the water toward the surface. Soon they were hauling him over the side of the _Nemo_ just when his senses were reeling. "Boy, you stayed too long," he heard Captain Austin saying as the helmet was lifted and he breathed again the pure air of the surface. He could only nod a reply. But within a few minutes he was himself again and able to talk. "What success, lad?" Captain Austin was eager to know how he had gotten along. Jay told him the story; how he had utilized the air hose in excavating the U-boat and how it now lay all exposed in its hastily improvised crater. "Some one had better go down right away and see if they can pry into that conning tower," he counseled. "No telling when those sands will commence to shift back again with the undertow." Immediately Dick Monaghan and Carl Weddigen stepped forward. "Please, sir, I'd like to take a shot at it," offered Dick. "Give me a chance, Captain; remember how I got along with the _Dominion_," pleaded Weddigen. Other members of the crew who were divers offered to take Jay's place and the captain for a moment was in a quandary. "Guess you better go down, Weddigen, and see what you can do by way of prodding that conning tower open," the _Nemo's_ executive decided. "You have big powerful arms and good lungs." At the same time, Austin winked at Jay, thinking Weddigen knew nothing of the plans in the U-boat. Turning to Dick the captain said: "I'll send you down after Weddigen works awhile, and we'll see what the two of you can do." So Weddigen hastily climbed into his diving suit and made ready to go. Weddigen went equipped with tools that he hoped to use in forcing an entrance into the submarine. He took along with him also the extra air hose since it was possible the sand was shifting again and he might find it necessary to do some more digging. After he had gone Jay and Dick engaged in earnest conversation. "That fellow's not to be trusted," remarked Jay tartly. "He may undo all that you've done," added Dick. "Yes, or get into that U-boat and make away with those navy plans." Jay had seen enough of Weddigen to give him the idea that the big fellow had ulterior motives behind his activities with the Bridgeford Salvage Company. After half an hour's wait Captain Austin told Dick to go ahead and get ready for a descent to the U-boat. "See how Weddigen's getting along. Maybe you can recover those plans yourself." The captain had confided to the two divers, Jay and Dick, that the coveted plans were contained in a stout steel box that would be found in a locker in the submarine's wireless chamber just forward of the main turret.