The chief-of-the-boat, an old-time chief gunner’s mate with years of submarine service, was standing by the “main induction,” which he was to close upon diving, and after that keep an eye on the other stations in the control-room, ready to supervise and help in any emergency. * * * * * In order to understand what happened, it will be best perhaps to explain that the main induction is a large air-intake or ventilating line, one part of which runs aft to the engine-room and motor-room, assuring a supply of air for the engines; the other leads forward to the torpedo-room, furnishing air to the forward part of the ship. These two parts join amidships in the control-room—which, as the name signifies, is where the ship is controlled when submerged—and forming an inverted T, pass through the upper part of the hull to the open air. The main induction must be closed before submerging, but should not be closed until the Diesel engines are stopped; for if by accident the conning-tower hatch were also closed, the engines would use up all the air in the boat in four or five revolutions. Should this occur—and it has occurred on some submarines with almost fatal results—everyone in the boat would drop as if shot, from collapsed lungs. So you can see that the chief’s station was an important one. As the hands of the control-room clock moved to eleven and the second hand came to zero, the order rang out: “Sound diving alarm.” “Aye-aye, sir,” came from the officer-of-the-deck, and the siren shrieked its call for action throughout the ship. Men jumped to their tasks. Air was hissing; sharp orders were given; a dozen things were being done at once. A single mistake, and the results might prove fatal to us all. The watch on the bridge slid down the hatch, the quartermaster staying in the conning-tower ready to close the conning-tower hatch the instant he heard the engines shut down. The chief-of-the-boat had his hand on the stop valve ready to close the main induction. The diving-rudder men had “Hard dive” on the diving planes. The Kingston sea-valves were being opened, flooding the six ballast tanks, three on each side of the ship. A slight list to starboard developed which rapidly increased to the point of danger. The chief-of-the-boat, seeing that the man at the Kingstons was having trouble opening the valves on the port side, so that water was flooding in the tanks on the other side only, thus tilting the boat heavily to the flooded side, jumped to help get the port valves open. Were my premonitions coming true? Or was this just one of those emergencies that submarine life is full of? While all this was happening, the engines had been shut down, the ship was going ahead on the electric motors, the conning-tower hatch was closed, the diving rudders were at “Hard dive,” and we were going down, down, down—with the main induction wide open and forgotten, all attention being focused on the other danger.