There were twenty Flying Fishes attached to the Allied Forces, all of them under the command of German engineers, with the exception of the original Flying Fish. Two of these were attached to the three squadrons which were attacking Hull, Newcastle and Dover: three had been detailed for the attack on Portsmouth: two more to Plymouth, two to Bristol and Liverpool respectively, on which combined cruiser and torpedo attacks were to be made, and two supported by a small swift cruiser and torpedo flotilla for an assault on Cardiff, in order if possible to terrorise that city into submission and so obtain what may be called the life-blood of a modern navy. The rest, in case of accidents to any of these, were reserved for the final attack on London.
When the Ithuriel disappeared and his torpedo struck a piece of floating wreckage and exploded with a terrific shock, John Castellan, standing in the conning-tower directing the movements of the Flying Fish, naturally concluded that he had destroyed a British submarine scout. He knew of the existence, but nothing of the real powers of the Ithuriel. The only foreigner who knew that was Captain Count Karl von Eckstein, and he was locked safely in a cabin on board her.
He had been searching the under-waters between Nettlestone Point and Hayling Island for hours on the look-out for British submarines and torpedo scouts, and had found nothing, therefore he was ignorant of the destruction which the Ithuriel had already wrought, and as, of course, he had heard no firing under the water, he believed that the three destroyers supported by the Dupleix and Leger had succeeded in slipping through the entrance to Spithead.
He knew that a second flotilla of six destroyers with three swift second-class cruisers were following in to complete the work, which by this time should have begun, and that after them came the main French squadron, consisting of six first-class battleships with a screen of ten first and five second-class cruisers, the work of which would be to maintain a blockade against any relieving force, after the submarines and destroyers had sunk and crippled the ships of the Fleet Reserve and cut the connections of the contact mines.
He knew also that the See Adler, which was Flying Fish II., was waiting about the Needles to attack Hurst Castle and the forts on the Isle of Wight side, preparatory to a rush of two battleships and three cruisers through the narrows, while another was lurking under Hayling Island ready to take the air and rain destruction on the forts of Portsmouth before the fight became general.
What thoroughly surprised him, however, was the absolute silence and inaction of the British. True, two shots had been fired, but whether from fort or warship, and with what intent, he hadn't the remotest notion. The hour arranged upon for the general assault was fast approaching. The British must be aware that an attack would be made, and yet there was not so much as a second-class torpedo boat to be seen outside Spithead. This puzzled him, so he decided to go and investigate for himself. He took up a speaking-tube and said to his Lieutenant, M'Carthy—one of too many renegade Irishmen who in the terrible times that were to come joined their country's enemies as Lynch and his traitors had done in the Boer War:
"I don't quite make it out, M'Carthy. We'll go down and get under—it's about time the fun began—and I haven't heard a shot fired or seen an English ship except that submarine we smashed. My orders are for twelve o'clock, and I'm going to obey them."
There was one more device on board the Flying Fish which should be described in order that her wonderful manœuvering under water may be understood. Just in front of the steering-wheel in the conning-tower was a square glass box measuring a foot in the side, and in the centre of this, attached to top and bottom by slender films of asbestos, was a needle ten inches long, so hung that it could turn and dip in any direction. The forward half of this needle was made of highly magnetised steel, and the other of aluminium which exactly counter-balanced it. The glass case was completely insulated and therefore the extremely sensitive needle was unaffected by any of the steel parts used in the construction of the vessel. But let any other vessel, save of course a wooden ship, come within a thousand yards, the needle began to tremble and sway, and the nearer the Flying Fish approached it, the steadier it became and the more directly it pointed towards the object. If the vessel was on the surface, it of course pointed upward: if it was a submarine, it pointed either level or downwards with unerring precision. This needle was, in fact, the eyes of the Flying Fish when she was under water.
Castellan swung her head round to the north-west and dropped gently on to the water about midway between Selsey Bill and the Isle of Wight. Then the Flying Fish folded her wings and sank to a depth of twenty feet. Then, at a speed of ten knots, she worked her way in a zigzag course back and forth across the narrowing waters, up the channel towards Portsmouth.
To his surprise, the needle remained steady, showing that there was neither submarine nor torpedo boat near. This meant, as far as he could see, that the main approach to the greatest naval fortress in England had been left unguarded, a fact so extraordinary as to be exceedingly suspicious. His water-ray apparatus, a recent development of the X-rays which enabled him to see under water for a distance of fifty yards, had detected no contact mines, and yet Spithead ought to be enstrewn with them, just as it ought to have been swarming with submarines and destroyers. There must be some deep meaning to such apparently incomprehensible neglect, but what was it?