When Calshot Castle was abreast, speed was increased to 30 knots. There was an easterly breeze blowing against the ebb-tide, with the result that quite a choppy sea was met with outside Southampton Water. Like a knife, the sharp cutwater of the Capella cleft the waves, sending up showers of white spray; but such was her speed that, before the wind could carry the spindrift on deck, the swift vessel was beyond the cascade of foam. She hardly felt the motion of the waves; indeed, she was so steady that it was possible to place a pail of water on deck without any of the contents being spilt by the "lift" of the ship.
Under the guidance of Noel Fox, the midshipmen made the round of the vessel, the Sub explaining everything to them in detail. Already the lads had taken a great fancy to the Sub, and Fox reciprocated the sentiment. He had a way about him that enabled him to give particulars of the most intricate mechanism without having to resort to dry, parrot-like instruction.
By the time he had explained the ingenious devices used to entrap the German unterseebooten, Ross and Vernon felt inclined to marvel how it was they found themselves on board the Capella, since only sheer good luck had saved U75 from being doomed during every hour of their brief and involuntary detention.
"Yes, we can mop up the German submarines quicker than they can turn them out," said the Sub. "Of course I don't mean to say that a few of them won't get a smack at some of our ships for some time to come; but all the same we are giving them beans. From a strictly professional point of view we would be sorry if Old Turps abandoned his 'effectual' blockade. Our chances of having a high old game with the unterseebooten would be considerably reduced."
"There are still some in the English Channel," hazarded Vernon.
"Yes, a few; but have you noticed how those fellows fight shy of Dover? They shun it like the plague. It's horribly unhealthy for them. D'ye know why? Perhaps you wouldn't have paid much attention to it, but some months ago the Admiralty issued a 'Notice to Mariners', stating that the Straits of Dover were heavily mined, and that all shipping was to pass through the Downs within three miles of the Kentish coast.
"So it's fairly safe to assume that the few stray unterseebooten that are still lurking in the Channel have made the passage round the north coast of Scotland. It's only a matter of time before we bag the lot, I fancy."
"And our submarines?" enquired Ross.
"Have fewer opportunities since the Hun battleships and cruisers have such a decided inclination to remain in harbour," rejoined Fox. "When there's a chance, you can bet your bottom dollar that our fellows seize it. Quite recently one of our submarines found herself alone and disabled in the Bight of Heligoland. Undismayed, her lieutenant-commander signalled to a passing German trawler, covered her with his guns, and made the Hun tow the crippled submarine into British waters. Then he released his involuntary benefactor, but before so doing can you guess what he did?"
"No," replied both lads.