Two hours later the rest of the flotilla was out of sight, although the dull rumble of gunfire proclaimed that the bombardment was still maintained. At four in the afternoon the North Hinder Lightship was sighted. From that point westwards there were no sea-marks, the Galloper and other light vessels off the Suffolk coast having been withdrawn.
Slowly the "Anzac" steamed, her rate being considerably less than Tressidar had anticipated. With the loss of the major portion of the funnel and the weak spot in her main steam-pipe her horse-power had fallen appreciably.
Night came on and with it a mist. Stellar observations were no longer possible. Navigation depended solely upon dead reckoning on a compass course and the constant use of the lead.
At midnight Tressidar, having previously instructed the quartermaster of the watch to awaken him should anything occur, lay down on the deck in the wake of the conning-tower. In less than a minute he was sleeping fitfully, the drums of his ears throbbing with the reaction after the deafening cannonade.
It seemed to him that he had been asleep but a few seconds when he was awakened by a dull, grinding noise and the quartermaster shouting to the engine-room for "hard astern."
The "Anzac" was aground.
"The men in the chains reported fourteen fathoms not a minute ago, sir," said the quartermaster. "The water must have shoaled like the roof of a house."
The hull was throbbing under the pulsations of the engines as the twin screws lashed cascades of phosphorescent water past the monitor's bulging sides. The ship showed no tendency to slide off. She had struck hard.
The sub. ordered the engines to stop. He knew that it wanted two hours to low water. Further attempts to get the monitor off must be deferred until after quarter flood, which would be at four forty-five in the morning.
Fortunately the sea was calm. There was little wind. At some distance away the sullen rollers were breaking heavily on the shoal. Since the monitor was not making water and lay on the lee side of the submerged bank, there was little danger. Provided the wind did not spring up, she would float without damage with the rising tide.