The three airmen took the hint. It was only on very rare occasions that the genial lieutenant-commander "choked any one off." It was an indication of the mental strain upon the skipper of the "Antipas."
"By Jove! if she does come up," thought Barcroft. "It will be Third Single to Perdition for a set of skulking pirates. The fog is lifting, too. I can distinguish the wave-crests nearly a cable's length ahead. We'll be into another patch in another minute, though, worse luck."
Suddenly the watchers on the destroyer's bridge caught sight of a short series of flashes slightly on the port bow, and perhaps at a distance of a mile.
In a trice Tressidar brought his binoculars to bear upon the glimmer of light, thanking Heaven as he did so that a rift in the fog enabled him to spot the presence of the hunted Hun. The powerful night-glasses revealed the outlines of a conning-tower and twin periscopes just emerging from the waves. Then as quickly as it appeared the light vanished. It was enough. The lieutenant-commander could still discern the patch of phosphorescence that encircled the partly submerged U-boat.
"Starboard ten!" ordered Tressidar, at the same time telegraphing for full speed ahead both engines.
Before the destroyer could work up to her maximum speed her knife-like bows rasped and bit deeply into the hull of the doomed unterseeboot. An almost imperceptible jar as the quivering vessel glided over her prey, a smother of agitated water on either hand, and the deed was done. Another of the modern pirate craft had been dispatched to its last home.
"Voices ahead, sir," shouted the look-out man. "Land ahead! By smoke! We've done it."
The engine-room telegraph bell clanged shrilly. As the propeller blades bit the water with reversed action the "Antipas" began to lose way. It was too late.
With a shock that threw almost every officer and man to the deck the destroyer charged bows on to a ledge of rocks. Her forefoot lifted almost clear of the water, while to the accompaniment of the hiss of escaping vapour from a fractured main steam-pipe, the "Antipas" buckled amidships.
"Clear lower deck! All hands fall in facing outboard!" ordered the skipper.