Amongst other mechanical devices R19 was provided with a heavy metal keel that in case of emergency could be released from within. Deprived of this anti-buoyant contrivance she would rise rapidly to the surface. It was a step to be taken only as a desperate resort, for before the compensating water-ballast tanks could be filled several precious minutes must necessarily elapse, during which time the submarine would be a target for every quick-firer within range. "Very good, sir," replied Macquare. He was quite content to accept his chief's decision without question. Not having been asked his opinion on the matter, he offered none. He was one of those men who knew how to give orders and receive them. Even if he were convinced in his own mind of an error of judgment on the part of his skipper, his strict adherence to the principles of discipline would have kept him silent. For another six long-drawn hours the blinded submarine lay motionless. Fortunately there were no signs of the hull plating collapsing under the weight of the obstruction. Apart from the slight, almost imperceptible, leak in the roof of Fordyce's cabin --for the artificers had tackled the job promptly and effectually--the hull of R19 was as tight as a bottle. "We'll risk it now, I think," declared the Hon. Derek as he consulted his wristlet watch. "Start the auxiliary ballast-tanks first and see how she likes it." The powerful, double-action pumps quickly ejected the water-ballast. In ordinary circumstances the submarine should have risen to the surface. She showed no tendency in that direction. Without any exhibition of liveliness she lay obstinately on the bed of the sea. "Nothin' doin'!" commented the Hon. Derek. "Give her half speed ahead." The dynamos purred. The hull trembled under the action of the twin propellers. Whether the submarine was forging ahead was a matter for speculation. Certain it was that she was failing to respond to the deflection of the horizontal diving-rudders. "Stop! Half speed astern." Beyond an increased reverberation of the hull nothing resulted. Even when the Lieutenant-Commander took the somewhat desperate step of ordering full speed astern R19 failed to respond. "Blow main ballast-tanks," was the next order. The submarine now showed a certain liveliness, although in her present trim she ought to be floating with nearly six feet of freeboard. "She's trying to lift herself aft, sir," reported Fordyce. "Is she, by Jove!" exclaimed the Lieutenant-Commander. "Send all available hands for'ard, and see if that makes any difference." Quickly the men made their way to the first and second compartments, and, taking their time from the Lieutenant, ran from side to side as far as the congested state of the vessel permitted. At the same time the motors were running full speed astern. For full five minutes the manoeuvre was mantained without tangible result; then, with dramatic suddenness, R19 shot obliquely towards the open air.