Hyde was more cautious on the return journey. He was well within the limit that he had set himself. An hour and forty minutes later, the car drew up outside the coast-guard station.
"Captain Syllenger presents his compliments, Mr. Hyde, and requests your company on board," said Sub-lieutenant Barry when the Capella's boat arrived to take off the midshipman. "Ton my word, you haven't been long. We didn't expect you back before six o'clock."
Having received his guest, Captain Syllenger led the way to his cabin, Barry and Ross being included in the party. The skipper's face glowed with satisfaction when he had opened the envelope, for the signal as decoded was as follows:
"(words missing) closely patrolled. Unable to provide stores here. Will attempt removal of (word missing) from Station 123 on Friday night. Will signal from Station 125 at 1 a.m. on Saturday if possible. Transports leaving by Needles Channel at daybreak."
Following this was an explanatory note.
"Station 123 is stated to be in Keyhaven Marshes. Station 125 one mile west of white house at Milford-on-Sea."
"Humph!" ejaculated Captain Syllenger. "It looks as if there's trouble in store for some gentlemen of marked Teutonic sympathies. I only hope we'll have a chance of being off Station 125."
CHAPTER XIX. That Friday Night
Three hours later H.M.S. Capella received the following order by wireless:—
"Await relief by Taurus, then proceed to Rendezvous Y, Portsmouth Command. Capella to be temporarily attached to Western Inner Patrol."
The meaning of the message was plain to all on board. The Capella was to proceed to Rendezvous Y, which according to Admiralty instructions was off Yarmouth, Isle of Wight, where a flotilla of small craft was patrolling day and night, as a precautionary measure in the unlikely event of any hostile craft forcing the formidable defences of the western entrance to the Solent.
At eight on the following morning the Taurus arrived on the station, and with the least possible delay the Capella made for the west'ard.
Only one incident marked the run. A few miles from the Royal Sovereign Lightship, the Capella sighted a number of submarines running on the surface. They were on Particular Service, and although opportunities for torpedoing a hostile surface craft were very remote, the submarines were constantly rendering yeoman service by keeping the approaches to the German North Sea ports under close observation. On rare occasions, when a German light-cruiser or destroyer did venture beyond the protection of the mine-fields and guns of the land-batteries, British submarines were not backward in seizing their chance of letting loose "tinfish" against their quarry.
Having arrived off Yarmouth, Captain Syllenger reported himself to the senior officer. He came back beaming. The Capella was to take part in combined sea and land operations for the capture of the German agents, who were supplying petrol to one of the submarines, and also for the capture of the U-boat.
The eventful Friday evening came at last. The Capella, in company with four first-class torpedo-boats, was to be ready at a signal from Hurst to make a dash through the North Channel. A fleet of armed trawlers from the Poole base was to operate farther out to sea, in order to cut off the U-boat's retreat should she be lucky enough to escape the attentions of the Capella and her consorts.
At ten o'clock the east-going tidal stream began to set through the Needles Channel. Half an hour later it ran with a velocity exceeding five knots. The Capella, moving at a rate equal to that of the tide, kept about half a mile from the Isle of Wight shore, with the white, occulting light of the Needles just visible to the north of Cliff End Fort.
It was a perfectly calm night, overcast, but with no wind. A dull rumble, rising and falling in volume, could be heard from the direction of the open sea.
"Breakers on the Shingles—a large bank on the starboard hand of the Needles Channel," explained Barry in answer to the midshipmen's enquiry.
"Then it means that bad weather is approaching," said Ross, who had had plenty of opportunities of observing the phenomenon of "ground swells" on the North Cornish coast. "If it's like this, the U-boat won't be able to make direct communication with the shore."
The appearance of Captain Syllenger on the bridge put an end to conversation. The officers, by the aid of telescopes and binoculars, kept the Hampshire shore under close observation.
To the naked eye nothing was visible but a dark bank of trees. Not a light was to be seen, although there were several houses in the vicinity. The position of Lymington, in time of peace discernible by reason of a strong blaze of light, could only be determined by the feeble glow of the high red light marking the course up the river.
"It's nearly midnight," observed the skipper. "If our friends the Germans are going to shift their supplies from here to Milford, they'll have to be pretty sharp. Seems to me like a case of 'nuthin' doing'."
Hardly were the words out of his mouth, when the silence was broken by a peremptory hail. The sound travelled clearly across the water, although the person shouting must have been a mile and a half away.
Then came the jumbled noise of men's voices, quickly followed by two rifle-shots. The voices then died away, and, as far as the listeners on the Capella could hear, all was quiet.
"That's soon over, whatever it was, sir," remarked Barry.
"Hurst calling up, sir," announced a signalman, as a light blinked rapidly from the fort guarding the Hampshire side of the narrow channel. It was the order to proceed at full speed to the position previously decided upon.
Although the torpedo-boats were speedy craft, the Capella left them behind "hands down". Fortunately there were no search-lights to baffle her quartermaster, for those of both Hurst and the batteries on the Isle of Wight shore had been previously switched off. Since the Needle Channel was closed to all mercantile shipping, the Capella could, and did, without risk, extinguish her navigation lights. Only the phosphorescent spray from her sharp cutwater marked her position.
Suddenly she ported helm, just in time to avoid a collision with a long dark shape that proved to be an unterseeboot in the act of diving. Her commander had detected the pulsations of the Capella motors, but he was too late.
Round spun the patrol vessel. From her quarter, a long length of something that resembled an exaggerated string of sausages was paid out. At the rate that the Capella was circling, it was impossible for the U-boat to escape from her toils. Dive to a safe depth she could not, since the maximum depth was but 5 3/4 fathoms.
The last of the "sausages", to which was attached stout flexible wire, disappeared beneath the water. Then a jerk upon the wire announced the gratifying fact that the fugitive submarine had fouled the string of sausages, which was in reality a number of gun-cotton charges, primed and connected to a powerful battery by means of an insulated wire.
Sub-lieutenant Fox, who was standing by the firing-key, needed no orders. His fingers pressed the ebonite disc. A hundred yards astern of the Capella a column of water was flying high in the air, followed by a tremendous roar. For one minute the vessel rocked violently in the agitated waters, then, circling, she made for the spot under which the explosion had occurred. With a splash a mark-buoy was dropped overboard to indicate the position of the shattered U-boat. By this time the torpedo-boats had arrived on the scene.