The officers embarked in the canvas boat and were rowed off to the submarine. Before going below, von Birmitz spoke to a seaman, who instantly semaphored to a German sentry stationed on the high ground at the entrance to the inlet. Crosthwaite had not noticed the fellow before. He now realized that he had run a great risk of detection, for, in his curiosity to overhear the conversation, he had approached so closely to the edge of the cliff as to be clearly visible from the place where the sentry from the submarine was posted. The seaman semaphored a reply, which was evidently satisfactory, for, rubbing his hands gleefully, the Lieutenant-Commander followed his guests down the narrow hatchway. A little later the submarine, the deck of which was previously only just awash, began to rise till she showed a freeboard of nearly six feet. Dick estimated that she was about three hundred feet in length, and considerably longer than the latest type of British submersible. Her conning-tower was of an acute oval section and apparently spacious. There were two periscopes, while abaft the conning-tower was a light signalling-mast supporting the wireless aerials. Fore and aft were short quick-firing guns mounted on water-tight disappearing platforms, while, owing to freeboard she exposed, the Sub could see the ends of a couple of broadside torpedo-tubes, both within ten feet of the 'midship section. "She carries six tubes at least," whispered Dick; "two on each side abeam and two in the bows. It's just likely she has a pair of stern tubes also. No wonder she wants a good supply of torpedoes; yet what has she done with those she brought with her? That fellow made no mention of having used any. Hello, she's getting under way." As he spoke, men hurried up from below. The propeller began to churn and the submarine gathered way. Describing a semicircle she slowed down, while a couple of seamen in the Berthon boat began to run a line ashore. To this was bent a stout hawser, which, as soon as it was made fast to the stump of a tree, was carried to a motor-capstan on deck. Slowly and with extreme caution the _unterseeboot_ was warped close inshore until it was possible for a man to leap from her deck on to dry ground. It was the only place in the creek where deep water existed close to the shore, for elsewhere the depth shoaled gradually. The work of replenishing the submarine's stock of petrol proceeded with the utmost dispatch, each large steel drum being carried to the beach by Turks, whence it was whipped on board by means of a light steel crane. The drums were quickly emptied into the vessel's tanks, and the empties taken ashore again and reloaded on the wagons. Nearly the whole morning was spent in taking on board the supply of petrol. According to Dick's estimate, the quantity was sufficient for a surface run of at least four thousand miles.