It was April 2, 1943. And at last, Commander Rodney Thomson of the Royal Navy reflected, the war news had taken a definitely brighter turn. The German thrust deep into Russia had dissolved into the debacle at Stalingrad; and in North Africa, American and British forces had the Desert Fox Rommel between them. The German army that had seemed so nearly invincible was suffering major setbacks and the land war on all fronts now looked hopeful.
But at sea, he knew, U-boats still prowled, and struck, and killed.
Commander Thomson stared anxiously into the blackness that surrounded his ship, the HMS Black Swan. It was a clear night, but quite dark, and he could not see any of the merchant ships that lumbered along in ragged rows behind him. A feeling of great anxiety, mingled with helplessness, hung over the convoy. The sense of lurking menace was so strong that it was almost a tangible thing.
The two freighters, Gogra and Katha, had been sunk since midnight, and the U-boat that had torpedoed them was still somewhere out there. Thomson knew he was waiting in the dark for another chance to attack.
Black Swan swept on in wide zig-zags ahead of the convoy, as the twenty-odd merchantmen behind her struggled to keep station in the dark. Convoy OS 45, now even with the Portuguese coast, had covered roughly a quarter of its long voyage from England to Freetown. As always, the U-boat Command would have known the approximate size and position of the convoy, and would have ordered a scouting line of U-boats to intercept. At least one boat had already found them. Thomson knew that other sleek grey hulls would be silently converging on them as the wolf pack gathered.
Strange how long a man could fight these predators without ever getting a glimpse of one. A U-boat could leave a convoy riddled with sinking and burning ships and not once be actually seen.
Survivors of sunk ships saw them sometimes. Thomson remembered stories about surfaced U-boats with odd emblems painted on their scarred conning towers--a playful dolphin, red devils, a fox's mask, and one with a flower--the edelweiss.
He glanced impatiently at his watch. Not too much longer until dawn.
"Radar reports a stray echo, sir."
Thomson was instantly all attention. "Give me the range and bearing."
The answer came back immediately. The radar operator was Able Seaman D. Hutson, clear-headed and competent. He had plotted the position of the convoy ships, and this contact now was ahead and to starboard. Hutson had recognized it for what it was--a surfaced U-boat.
"Hard starboard!" called Thomson, and braced himself as the sloop heeled over sharply to take the turn. Her engines hummed with a higher pitch and her hull shuddered with the increased vibrations as Black Swan headed toward the stray echo on a closing bearing. Her sharp prow sliced through the black water which foamed up in white and sparkling bow waves on either side, and her curving wake trailed out behind her.
HMS Black Swan was the first of the "Black Swan" class of anti-submarine sloops, a tough and fast 2,000-tonner, designed specifically for ocean escort duty. She was fitted with the latest in radar gear, eyes that could penetrate the blackest night to see a U-boat riding low on the surface. Black Swan also carried a formidable array of guns, including 6.4" high-angle/low-angle guns in twin mountings. There were two of these forward and one aft, and they had radar incorporated in their aft control. She also carried a number of Oerlicon and Bofors guns, as well as other anti-submarine weapons. She was designed and built for just one purpose--to kill U-boats.
Making her best speed of about 20.5 knots, Black Swan passed close ahead of the starboard wing ship which had loomed up suddenly in the dark. And with every man ready at his post, and every eye straining to penetrate the inky darkness, Black Swan raced toward the ominous echo.
The minutes dragged by. Perhaps the U-boat had already spotted them. Low in the water, she would have a ship in sight long before she was herself seen--unless the ship, like Black Swan, carried radar to see through the dark, and for distances far beyond the sharpest U-boat lookout's capabilities.
Thomson wondered what kind of hand the U-boat skipper was playing. It was highly possible (if not likely), that he had already seen the sloop bearing down on him. Then why had he not sheared off his own course to get out of the way? Was the U-boat, after all, holding the trump card? Thomson frowned. It was not comforting to think that his opposite number's glasses might be trained on him now, and a German fist poised over a torpedo firing button.
Perhaps the U-boat skipper was merely holding his own course expecting the sloop to turn off. He was almost into the convoy, and in the most favorable attacking position possible. Running in front of the convoy, Thomson had been patrolling in wide zig-zags. If the German did not know he had radar, he would have no reason to suspect that he was not on a leg of his regular search pattern. If this were the case, he would expect the sloop to turn away before reaching the U-boat.
The U-boat must surely have seen him by now. They had to be close, and he was still on the surface. Whatever else her stepper might be, he was cool--and determined. And only Black Swan stood between him and the convoy.
"Radar says he's lost contact, sir."
Thomson nodded briefly at the report. "Very well," he said. The U-boat might be lost in the "clutter," or he might have dived. If the latter were the case, they should soon pick him up on asdic.1
1. An underwater echo-ranging device, called "sonar" in the U.S.
"Tell Hutson to keep watching," he said unnecessarily, knowing the radar operator did not have to be told to do his best.
"There!" the lookout above him yelled. "Just off the starboard bow! U-boat, diving!"
Thomson could see the conning tower as it submerged, and he watched as it passed directly in front of the sloop, under water but still visible, some twenty meters ahead.
"Put depth charges on shallow setting!" he shouted.
There was not time to make a planned attack, but the advantage of surprise was on his side. Even if none of the depth charges hit the boat, they might be close enough to shake him up a bit and make it harder for him to evade the next attack.
The water was still boiling with exploding depth charges as Black Swan turned to make another run. The two asdic operators. Lieutenant W. A. Fuller and Able Seaman C. Rushton, reported a contact. Calling out the range and bearing at steady intervals, they guided the sloop precisely to where the U-boat was still desperately plunging downward.
When the explosions had died away, Fuller reported that he had lost contact.
They were now in danger of colliding with the merchant ships and Thomson called for a change of course. The corvette Stonecrop was arriving on the scene and she would finish the attack. Black Swan's place was now back in her position at the head of the convoy. They could not afford to leave the front unguarded for long.
Coming in at full speed, the Stonecrop, commanded by Captain Patrick Smythe, dropped a pattern of depth charges over the estimated position of the U-boat. When the corvette turned to make another attack, her asdic operator reported that he was unable to make contact.
As Stonecrop slowly recrossed the area, now quiet after the violence of exploding depth charges, a shout from a lookout electrified the men on the bridge. "Oil slick ahead!"
The corvette moved slowly through the large and spreading patch of diesel oil, carefully searching for proof of a kill, while her asdic probed in vain for a contact. Only the oil was to be found--the lifeblood of a U-boat, now spreading slowly over the surface of her last battlefield.
At last Stonecrop turned and sped away. This battle was over, and now her duties lay with the slow and vulnerable cargo ships which must be protected. Smythe knew other grey wolves were lying in wait for his charges, and he swung his tough little ship back into her station.
Toward the east, the first rosy light was breaking through the darkness. Soon the sun would turn the leaden sea to sparkling blue and green, and pick up rainbows in the dull patch of oil.