Directed by the aerial pilots the four swift craft converged. Then began a sort of marine waltz, the lively vessels dodging to and fro, circling and crossing each other's bows in a most daring fashion —all with the idea of confusing the fugitive U-boat.
In this they succeeded. With their nerves shaken by the narrow escape from the explosions of the torpedoes, and in the knowledge that they were hunted by an unknown number of the dreaded patrol-boats, the Huns were literally in a panic. Their sole idea was to keep at a safe depth and steal away from their pursuers, trusting that the latter would be unable to discern their presence by the "surface wake" and the trail of air-bubbles.
But the U-boat had reckoned without the sea-planes. Remorselessly, the wireless reports from the observers kept the patrol-boats in close touch with their prey. Ceaselessly, the churning of the small yet powerful propellers betokened the grim fact that for once the modern pirate could not shake off pursuit.
Suddenly a huge air-bubble rose to the surface, agitating the water in ever-widening circles. No. 0916, fairly in the thick of the maelstrom, was swept from fo'c'sle to taffrail. Then, almost as quickly as it had risen, the sea calmed down under the influence of a rapidly-spreading patch of iridescent oil.
"How about it?" wirelessed No. 0916.
"Get out of the light and we'll see," was the sea-plane's laconic reply. Then a minute later: "She's properly strafed."
In her blind dash for safety the U-boat had crashed, bows on, against a rock that rose abruptly for ninety feet to within nine fathoms of the surface. In spite of her strong construction the steel bows collapsed like an egg-shell. An inrush of water under terrific pressure followed, and yet another of the Kaiser's boasted submarines had ceased to exist, save as a waterlogged wreck upon the bed of the Mediterranean.