Slowly the minutes passed. UC49 was still running submerged, increasing the depth to twenty fathoms and maintaining a zig-zag course in order to baffle her pursuer. The German seamen were beginning to breathe more freely. The worst part of the business--the great risk of being rammed as she dived--was over, and although under the enormous pressure jets of water were hissing through the faulty joints the men realised that they stood more than a fighting chance of evading destruction. For perhaps five hours UC49 blindly made her way under the waves. The captives had lost all count of time. Their watches had stopped owing to their immersion when the seaplane was sunk; there was no clock in the fore compartment nor were the bells struck in the customary style on board. But at length, after a seemingly interminable interval, the order was given to empty the auxiliary water ballast tanks. Simultaneously the floor assumed a list--this time in a contrary direction. Then, without warning, the fairly regular throb of the electric motors gave place to a discordant jar that shook the hull from end to end. "Main shaft gone, for a dead cert," exclaimed Kirkwood. "I remember the same thing occurring on the 'Tremendous's' picket-boat Yes, they're switching off." The mine-layer was helpless. Without means of propulsion there were only two courses open to her--to float or sink to the bottom. It was impossible to keep submerged to a certain depth simply by means of admitting a certain quantity of water ballast. Once the reserve of buoyancy was overcome she would sink to the bed of the North Sea, in all probability collapsing under the terrific pressure on her hull long before she arrived there. It is only by means of the diving rudders acting in conjunction with her diving trim that a submarine can remain submerged to a required depth; and since the kapitan-leutnant of UC49 had no desire to make the acquaintance of the floor of the ocean other than by means of an "armed" lead-line, he chose the other alternative and rose to the surface. The moment the fore hatch was removed the watch rushed on deck. There was a lot of scuffling and shouting of orders, accompanied by the clanking of the auxiliary motors actuating the bilge pumps. When the main shaft fractured--the submarine had only one "screw"--the propeller had flown off, taking with it the broken tail shaft and straining the stuffing-box to such an extent that water poured through the glands. The pumps were just able to cope with the inrush. Should they choke or otherwise get out of order the vessel would promptly founder. Another order was given. Those of the crew who still remained below hurriedly collected their personal belongings and went on deck, while their place was taken by their companions who, following their example, set to work to "pack up" their scanty bundles. In five minutes the crew space was untenanted save by Fuller and Kirkwood.