The next salvo-obviously the hit on the enemy cruiser hadn't affected her fire-power, fell a cable length's astern.
The German was now firing blind.
Engineer Commander Dodson was making smoke with a vengeance, the oily, black smoke flattening down on the surface of the sea, rolling, thick, impenetrable.
Vallery doubled back on course, then headed east at high speed.
For the next two hours, in the dusk and darkness, they played cat and mouse with the "Hipper "class cruiser, firing occasionally, appearing briefly, tantalisingly, then disappearing behind a smoke-screen, hardly needed now in the coming night.
All the time, radar was their eyes and their ears and never played them false.
Finally, satisfied that all danger to the convoy was gone, Tyndall laid a double screen in a great curving
"U," and vanished to the south-west, firing a few final shells, not so much in token of farewell as to indicate direction of departure.
Ninety minutes later, at the end of a giant half-circle to port, the Ulysses was sitting far to the north, while Bowden and his men tracked the progress of the enemy.
He was reported as moving steadily east, then, just before contact was lost, as altering course to the south-east.
Tyndall climbed down from his chair, numbed and stiff. He stretched himself luxuriantly.
"Not a bad night's work, Captain, not bad at all.
What do you bet our friend spends the night circling to the south and east at high speed, hoping to come up ahead of the convoy in the morning?"
Tyndall felt almost jubilant, in spite of his exhaustion.
"And by that time FR77 should be 200 miles to the north of him... I suppose, Pilot, you have worked out intersection courses for rejoining the convoy at all speeds up to a hundred knots?"
"I think we should be able to regain contact without much difficulty," said the Kapok Kid politely.
"It's when he is at his most modest," Tyndall announced, "that he sickens me most... Heavens above, I'm froze to death...
Oh, damn!
Not more trouble, I hope?"
The communication rating behind the compass platform picked up the jangling phone, listened briefly.
"For you, sir," he said to Vallery. "The Surgeon Lieutenant."
"Just take the message, Chrysler."
"Sorry, sir.
Insists on speaking to you himself."
Chrysler handed the receiver into the bridge.
Vallery smothered an exclamation of annoyance, lifted the receiver to his ear.
"Captain, here.
Yes, what is it?...
What?...
What I Oh, God, no!...
Why wasn't I told?...
Oh, I see.
Thank you, thank you."
Vallery handed the receiver back, turned heavily to Tyndall.
In the darkness, the Admiral felt, rather than saw the sudden weariness, the hunched defeat of the shoulders.
"That was Nicholls." Vallery's voice was flat, colourless. "Lieutenant Etherton shot himself in his cabin, five minutes ago."
At four o'clock in the morning, in heavy snow, but in a calm sea, the Ulysses rejoined the convoy.
By mid-morning of that next day, a bare six hours later Admiral Tyndall had become an old weary man, haggard, haunted by remorse and bitter self-criticism, close, very close, to despair.
Miraculously, in a matter of hours, the chubby cheeks had collapsed in shrunken flaccidity, draining blood had left the florid cheeks a parchment grey, the sunken eyes had dulled in blood and exhaustion.
The extent and speed of the change wrought in that tough and jovial sailor, a sailor seemingly impervious to the most deadly vicissitudes of war, was incredible: incredible and disturbing in itself, but infinitely more so in its wholly demoralising effect on the men.
To every arch there is but one keystone... or so any man must inevitably think.
Any impartial court of judgment would have cleared Tyndall of all guilt, would have acquitted him without a trial.
He had done what he thought right, what any commander would have done in his place.
But Tyndall sat before the merciless court of his own conscience.
He could not forget that it was he who had re-routed the convoy so far to the north, that it was he who had ignored official orders to break straight for the North Cape, that it was exactly on latitude 70 N., where their Lordships had told him they would be, that FR77 had, on that cold, clear windless dawn, blundered straight into the heart of the heaviest concentration of U-boats encountered in the Arctic during the entire course of the war.
The wolf-pack had struck at its favourite hour-the dawn, and from its favourite position, the north-east, with the dawn in its eyes.
It struck cruelly, skilfully and with a calculated ferocity.
Admittedly, the era of Kapitan Leutnant Prien-his U-boat long ago sent to the bottom with all hands by the destroyer Wolverine, and his illustrious contemporaries, the hey-day of the great U-boat Commanders, the high noon of individual brilliance and great personal gallantry, was gone.
But in its place-and generally acknowledged to be even more dangerous, more deadly, were the concerted, highly integrated mass attacks of the wolf-packs, methodical, machine-like, almost reduced to a formula, under a single directing command.
The Cochella, third vessel in the port line, was the first to go.