The German batteries had hitherto deferred opening fire for fear of damaging the submarine, which had left Zeebrugge and had made a circuitous course through Dutch waters. Having allowed her ample time to get clear of the danger zone, the Huns had begun to fire.
"Hang it all!" ejaculated Tressidar. "We'll have to send for the destroyers after all to finish the job."
But there was yet a respite, for the "Anzac" and two of her consorts were standing in and interposing themselves between the shore and the boats. In a few minutes the action became general, the 14-in. guns hurling their shells with terrific precision upon the hostile batteries.
Slowly the tide rose, and with it the strain of the hawsers began to take up. Deeper sunk the hulls of the steamboats, but the submarine showed no signs of leaving her muddy bed.
Unconcernedly the boats' crews "stood by," though not without risk, for, although the monitors successfully drew the enemy's fire, ricochets from the German guns came perilously close.
Suddenly bubbles appeared on the surface alongside the "Anzac's" picquet-boat's quarter, and with them a metal cylinder shot up from beneath the water. To it was attached a light line and a canvas tally on which was roughly scrawled the word "Communication."
"Steady, there," cautioned Tressidar, as one of the seamen prepared to fish up the object with his boat-hook. "Pass the bight of the line under it."
Ordering easy ahead, the sub. allowed the picquet-boat to travel as far as the scope of chain permitted, at the same time taking a steady strain with the bight of the rope until the cylinder broke away from the line that led to the submarine. Nothing happened so far as an explosion was concerned, for the sub. had his suspicions that there might have been a ruse on the part of the trapped Huns.
The cylinder was roughly twelve inches in diameter and two feet in height. It was one of a regular pattern supplied to German submarines for sending communications to the surface in the event of the vessel meeting with an accident that prevented her from rising. The diameter, being exactly the same as that of the torpedo-tubes, enabled the canisters to be discharged through them by means of compressed air.
"What sort of a haul have you got there, Mr. Tressidar?" enquired the lieutenant. "H'm, communication, eh? Suppose it's all right. There's no detonating mechanism inside, I hope?"