Suddenly Ned gave a shout and pointed ahead.
"Look, sir, look!" he cried.
Not more than a hundred feet from them a rubicund object, which a second glance showed to be Herc's head, was bobbing about on the waves.
But the water had by this time grown dark and oily-looking. The approaching squall would burst in all its fury in a few minutes.
The work of saving the swimming lad must be accomplished within a brief few minutes, or not at all.
"Hold on, my lad, we'll get you," hailed the ensign encouragingly, as the wherry drew closer and closer to the plucky boy.
"Aye, aye, sir," hailed back Herc, expelling a thin stream of water from his lips and giving a cheerful grin; "but hurry up, for I've forgotten my lightning-rod, and it looks like thunder."
But, just as Herc's easy rescue seemed a matter of certainty, the intentions of his saviors were interfered with in a startling fashion.
It was Ned who saw the impending peril first.
"Look! Look there!" he shouted. "What's that, sir?"