Even as he spoke, a bright flash blazed up from the strange vessel's deck. It only lasted a few seconds, but in that brief space it lit up the mysterious stranger, showing a huddled mass of men in her waist and throwing into sharp distinctness every rope and spar.
"A flare," cried Walter, "they are certainly signaling some one."
"There is something familiar about those spars," Charley exclaimed. "Did you notice them, Captain?"
"No. I was looking at the hull. She sits low as a pirate craft. She's schooner rigged and about one hundred tons burden. Hallo! Here comes some one who has heard her signals. We can find out about her all right."
From the bay came the quick chug chug of a motor turning up at full speed. As she swept into the passage, the little party could tell even in the dim light that she was a large launch and traveling at a rapid rate.
"Ahoy!" hailed Charley, as the strange launch came abreast.
The launch's engine was stopped at his call, but no answer came to his hail.
"Ahoy!" he shouted again. "Can you tell us what ship that is and what she wants?"
A string of low-muttered curses came from the launch, and almost at the same minute a single fiery rocket hissed aloft from her deck. Immediately her engine began to throb again.