A glance at a chart, or even at a map of the AEgean Sea, will give some idea of the intricate navigation that called for Osborne's skill and courage. Dozens of islands lay athwart the direct course, reefs abounded, while intricate currents traversed this part of the tideless sea in directions that were hardly ever constant. A change of wind might divert the current eight or ten degrees without having any appreciable effect upon its velocity, while, in addition, the islands were badly lighted, especially during this critical epoch in the history of modern Greece.
Throughout the night Osborne remained on deck, standing in the low wheel-house beside the helmsman. Fortunately the sea was calm and the glass high, while there was little or no shipping about, which was as well, since No. 0916 and her tow were without navigation lights.
When day broke, the Lieutenant snatched a few minutes' well-earned rest, awaking to find Sub-lieutenant Webb touching him gently on the shoulder.
"Yes, fit as ninepence," replied the Sub in answer to Osborne's enquiry. "But that's not the reason why I roused you. There's a strange-looking packet coming up astern. She's overhauling us pretty rapidly."
Osborne leapt from his bunk, buckled on his belt, and rammed his cap on his head the rite of "dressing" when on active service.
"Is she showing her colours?" he asked.
"Nothing," replied Webb. "We signalled her, but she took no notice."
Upon gaining the deck the Lieutenant found that the overtaking vessel was a steamer of about five hundred tons. She looked like a yacht with her schooner bows, raking masts, and white topsides. He estimated her speed at about fourteen knots, and since she was following almost in the wake of No. 0916 and her tow, it seemed fairly evident that she was desirous of making a closer acquaintance with the patrol-boat.
The unanswered signal, "What ship is that?" still fluttered from the yard-arm of the patrol-boat's diminutive mast, and since the wind was blowing steadily abeam there could be no doubt of the ability of the stranger to read the flags.
That in itself was suspicious; yet what hostile nation was there that would dare to send a vessel, other than a submarine, into waters firmly held by the Allied fleet? And of the countries bordering the Mediterranean Sea the only one strictly neutral was Spain. It was very unlikely that a Spanish yacht would be cruising in these waters, and especially so for her to stand in pursuit of a British armed craft.