Mentally Ross compared the on-coming battleship with an express train, as shown on a cinematograph screen, in the act of approaching the audience. At one moment the ship was visible from her water-line to the truck of her top-mast; at the next her bulk had suddenly expanded and seemed to fill the complete field of vision. It looked as if the two lads, in spite of the distance they had put between themselves and the motionless submarine, would yet be in the way of the vengeful battleship, whose extreme beam was not less than ninety feet.
Yet neither of the two chums made the slightest effort to swim farther away. Mechanically treading water, they waited and watched.
They could see the terror-stricken attitudes of the crew of the doomed U75. They heard the shouts of consternation as the massive steel bows bore down upon her. Then, in a second it seemed, there was a hideous crash that outvoiced the yells and shouts of despair as the unterseeboot was rent in twain.
Of what happened during the next minute the lads had but a very hazy idea. Caught by the irresistible bow wave as the Tremendous tore past, they were hurled aside like feathers and buried a couple of fathoms down under the breaking, foaming mass of water. Vaguely they heard the whirring of the four propellers—very near, it seemed; then, caught by an eddy caused by the cavitation in the wake of the monstrous vessel, they were separated and flung to the surface, half-breathless and dazed.
Ross opened his eyes. The Tremendous had already covered nearly a quarter of a mile. Twenty yards away he saw his chum's head, as Vernon, puffing like a grampus, was striking out towards him.
Where the submarine had dived for the last time was an ever-widening circle of oil. Those of the German crew who had not been carried down by the sinking unterseeboot were too shaken by the concussion to make any great effort to save their lives. Attempting to keep afloat in that oil-covered water added to their difficulties, for whenever the head of a swimmer disappeared he did not rise again.
"Kick off your boots, old man," exclaimed Ross.
"Where are the lifebuoys?" asked Vernon as he carried out his friend's advice.
One buoy had disappeared; the other was supporting a seaman, the only survivor of the crew.
"A case of finding's are keeping's," announced Ross. "We can't sling him out of it. It might support two people. We could take turns at hanging on."