Seizing the Enigma (49 page)

Fifteen minutes later, the teletypewriter tapped out another solved German message. Sent ten hours after the first, it instructed the U-66’s captain, Lieutenant Friedrich Markworth, where and when to get supplies: “Beginning 3 August 15 2000B Markworth ((66)) will provision from Neumann ((117)) in Sq 6755 ((probably CD 6755 = 37.57 N – 38.30 W)).… After execution Markworth report affirmative, Neumann wait in that area.”

The day after these messages went to F-21, Cominch headquarters radioed the information to units at sea that could use it. It was included in the U-boat report for August 2. Not giving the source of the intelligence, the report stated: “Several [U-boats] area 3800 [north] 3830 [west].” The data were repeated in the next day’s report, with a cover source: “Several vicinity 3800 3830 by recent DFs suggesting refueling operations X.”

One of the recipients was the U.S. Navy’s Combat Task Group 21.14, a convoy support group consisting of the escort carrier
Card
and three old destroyers. The U-boat situation reports told its commander, Captain Arnold J. (Buster) Isbell, where to look for subs to sink. He knew that if refueling, they could be caught at a particularly vulnerable moment—moving slowly on the surface, joined by a fuel hose—and that one of them would be a particularly valuable target. He headed toward the reported U-boat concentration while his planes scouted ahead and to the sides.

*     *     *

Late in the afternoon of August 3, as the
Card
was perhaps 150 miles from that area, two of his pilots, reserve Lieutenant (j.g.) Richard L. Cormier, in a Grumman TBF-1 Avenger torpedo-bomber, and his wing-man, reserve Ensign Arne S. Paulson, in a Grumman F4F-4 Wildcat fighter, making a routine submarine search, were flying southwest at 5,000 feet in clear skies when Cormier, with his binoculars, spotted a grayish white submarine off to port about 11 miles away. She was fully surfaced, cruising so slowly that no bow wave or wake was noticeable. It was the U-66.

Paulson, on Cormier’s orders to strafe the submarine, gave his fighter full throttle and, 100 feet above the waves, raced directly at the U-boat. At 500 yards, he began firing and saw his bullets strike the conning tower, kicking up puffs of rust. He saw nobody; on the U-boat, however, a machinist who was topside smoking was wounded in both thighs. Cormier then swept in to depth-charge the U-boat, but the charges failed to release. As he circled to attack again, Paulson made another run. It was met at this time with inaccurate antiaircraft fire from the six or eight men now topside. The attack had, however, killed the submarine’s second watch officer and panicked the men in the conning tower into ringing the diving alarm. But Markworth, demonstrating anew why he had won the Knight’s Cross, bulled his way up the ladder, belayed the command to dive, and held his men to their guns.

In his torpedo-bomber, Cormier sped toward the U-boat, skimming the water. He pressed his electrical bomb release and immediately pulled the emergency release. This time his acoustic torpedo and both depth charges dropped. Within seconds, while making a climbing turn, he saw a shock wave centered about 25 feet from the submarine’s starboard side and just forward of her conning tower. It swept to her port side and appeared to lift her from below and make her list to port. Then a heavy column of water about 100 feet high obscured the U-boat. When she reappeared, she was turning to starboard. Paulson attacked again. He saw half a dozen figures,
some inert, on the conning tower. His shots killed one sailor who had kept firing despite several wounds, wounded another in the chest, and slightly injured six others. No further fire was returned. Cormier strafed, seriously wounding Markworth in the abdomen. Then it became clear to the men on the submarine that the planes had no more bombs and that it was therefore safe to dive, so the first watch officer gave the order. The bodies of the officer and the seaman had to be left where they were. Slowly at first, and then more rapidly, at an angle of 50 degrees, the U-boat submerged. Just as she was disappearing, Paulson made a final run, firing at the underside of the stern.

Cormier dropped a marker and circled over the spot for forty-five minutes. Though neither he nor the pilots of the other planes that the
Card
sent saw any debris, oil, or air bubbles, the squadron commander claimed a sinking. He was wrong. Though the U-66 had two fatalities, several seamen wounded, and a captain suffering from a bullet in his guts, and though her ballast and fuel tanks were leaking, she had escaped.

But she still had not met the U-117. She limped east toward home, with not enough fuel to make it and only two days’ worth of provisions. The next day, after midnight, she surfaced. Though the sailor’s body had washed overboard, the second watch officer’s body was, ghoulishly enough, still on the lower machine-gun stand. It and the body of a sailor who had died from his wounds were buried at sea.

Meanwhile, Buster Isbell on the
Card
was being further tantalized by F-21’s U-boat situation reports to his carrier task group telling of combat and tanker submarines nearby. On August 6, for example, he was told, “One probably refueler locality 3915 3730 by DFs 052330 and 052350 probably moving NE.” By 2
P.M.
, he was steering for that area.

That same day, the U-66 proposed a new rendezvous with the U-117 for that noon, some 54 miles north and 12 miles east of the August 1 meeting place. Dönitz acquiesced a few hours later. The Allied cryptanalysts
could not read these messages as promptly as the others, and they remained a closed book. But the Tenth Fleet’s
ULTRA
-based knowledge of the rendezvous attempts, together with its background information that on July 30 the U-117 had been ordered to stand by within 100 miles of 38° 50′ north, 37° 20′ west, a circle within which the August 1 rendezvous was to have been effected, made it worthwhile to keep the
Card
in the vicinity.

Shortly before noon on Friday, the U-117 and the U-66 finally met. After dark the combat submarine took aboard some provisions and a physician to treat Markworth. But, unable to refuel at night, the pair waited for morning. With daylight, the U-66 began to take on oil. At just about the same time, 6:49
A.M.
Saturday, the
Card
flew off the same kind of airplane pairing as had attacked the U-66, an Avenger and a Wildcat. An hour into the patrol, however, the Wildcat had to return to the carrier because of engine trouble. The Avenger, piloted by reserve Lieutenant (j.g.) Asbury H. Sallenger, continued its routine submarine search. At 9:46, while flying west-northwest at 4,500 feet in a cloudless sky, Sallenger spotted a large white object 15 miles off his starboard bow. He thought at first it was a merchantman, but he soon realized that it was two submarines, painted white, close together, fully surfaced and proceeding very slowly southwest, with neither bow waves nor wakes. The refueling was still in progress.

Sallenger radioed the
Card
, 82 miles away, and maneuvered to attack. Selecting the U-boat nearest him, which was slightly behind the other, he approached from the port quarter at 220 knots, out of the sun. “This is it!” he told his crew. The U-66, spotting him, shoved the throttles of both diesels to full speed ahead. When Sallenger was about 400 yards from the subs, both opened fire with their 20-millimeter guns. These filled the sky with white puffs, but Sallenger bored in and, from about 125 feet, dropped two depth charges, set to explode at 25 feet. They straddled the U-117. Three seconds later the explosions raised two columns of water on the starboard side, one about 10 feet out, the other some 20 feet out,
cutting the refueling hose. Sallenger banked to the left and climbed. The submarine spurted flame from its stern, and dense gray smoke rolled out. The TBF’s turret gunner, Ammunition Mate Third Class James H. O’Hagan, Jr., sprayed the deck with his .50-caliber machine gun, then concentrated his fire around the machine guns on the conning tower. He saw about twenty men. The radioman took pictures, which would be used to improve tactics.

The U-boat began maneuvering erratically, as if her steering apparatus had been damaged. She started to trail a heavy oil slick. The U-66 was following her, seemingly trying to help. After about fifteen minutes, the undamaged U-66 started to submerge, apparently in an attempt to save at least herself. While she was thus vulnerable, Sallenger, who had been watching from 6,500 feet, dove to attack. As he flew along her track at 130 knots in level flight, 200 feet up, the U-117 threw intense antiaircraft fire at him. O’Hagan fired back. Sallenger dropped his acoustic torpedo on the last seen course of the submerged U-boat, 150 yards ahead of the diving swirl and 50 yards to starboard some forty seconds after she disappeared. Sun glare prevented him or his crew from observing any results. But the U-66 escaped.

His armament exhausted, Sallenger soared to 6,400 feet to vector in the other planes. As he circled, the damaged U-tanker tried to dive. For a moment, Sallenger thought she was gone, but she surfaced almost immediately. At 10:33
A.M.
, twenty minutes after his second attack, two Avengers and two Wildcats arrived from the
Card.
On command, one of the fighters made a strafing run. He fired a test burst from 2 miles away, but the bullets fell short, and he held his fire until he was in range. During his run, gun flashes from the 20-millimeters at the base of the conning tower winked at him, and he concentrated his fire on this area, though he saw no gunners; apparently they were well protected. He swooped around and attacked from the other side. But the U-boat continued her heavy antiaircraft fire, which forced the lead Avenger, flown by Lieutenant Charles R. Stapler, to weave as it bored
in. In a shallow dive, Stapler released two depth charges at 185 feet. They fell close aboard the port side just ahead of the conning tower, and the explosion drenched the submarine. As Stapler pulled up, his gunner strafed the vessel. The first fighter again attacked, and so did the second, just before the second Avenger, coming from the U-boat’s stern, dropped its two depth charges 20 to 25 feet from the submarine on her starboard quarter. Spray covered her. The fighters zoomed down to strafe some more, finally silencing the antiaircraft fire.

As the two Avengers circled, the crippled U-117 turned to starboard, apparently trying to dive but instead only mushing down, stern first. Then she did go under, and the Avengers turned to attack with their acoustic torpedoes. But they pulled up when the bow and conning tower broke water and the submarine, now barely moving, struggled to surface. Quantities of oil leaked from her. After five minutes, she lost the fight. She began to settle. Her stern went down, her bow rose slightly; the conning tower slipped under, then the bow, and she was gone. Now the Avengers could use their acoustic torpedoes. Stapler dropped his 200 feet ahead of the oil slick and 100 feet to starboard of the U-boat’s last track. Ten seconds later, the other Avenger dropped its 400 feet ahead and to port of where the pilot had last seen the submarine. Some distance away, the crew of the U-66, still submerged, heard detonations, some sharp, some muffled.

The Avengers circled. A patch of oil 200 feet in diameter where the submarine had last been seen seemed to grow. The radioman of the second Avenger reported seeing a shock wave in the water forward and to starboard of the same point. The U-66 heard crackling noises, and finally sounds that the crew interpreted as those of a boat sinking. The airmen saw a very light blue area that seemed to be caused by small bubbles aerating the water. This persisted for many minutes. Nothing else was seen. At 11:26 the four planes were recalled to the
Card.
They were relieved by three Avengers which, however, saw neither submarine. Though Isbell claimed that one submarine had been “definitely sunk” and the other “probably sunk,” he was
only half right. The U-66 had escaped. But the U-117 had made her last dive. She had gone down about 17 miles north and 40 miles west of where the August 6 U-boat situation report had told Isbell that “probably refueler” would be found. In the vast wastes of the ocean, that was practically pinpointing the target.

Reporting the episode early Sunday morning, the U-66 did not tell U-Boat Command about the detonations she had heard. U-Boat Command, assuming that the U-117 had survived, gave both submarines a new rendezvous for noon. Later the command observed that with the loss of another milch cow, the last fuel reserve for boats coming from the south had been exhausted, and all fourteen had to refuel now from the U-117. But when the U-66 reported on Wednesday that it had waited two days in vain for the U-117, and when the tanker failed to respond to orders to report, the command concluded that she had been lost during the attack. The critical supply situation forced U-Boat Command into complicated maneuvers: some combat submarines had to give fuel to other boats, then return home using fuel as sparingly as possible. The U-66 made it. The loss of the tankers, Dönitz complained, forced him to end operations in the mid-Atlantic earlier than planned.

Between June and August, American carrier planes, aided by
ULTRA
, sank five milch cows and reserve tankers. The British lost all reservations about using Enigma intelligence in these operations. On October 2 the Admiralty asked the U.S. Navy whether it could send a task force against a refueling to take place north of the Azores; Navy planes found four U-boats on the surface and sank the milch cow U-460. A similar request less than a week later ended in the sinking of the combat boat U-220. By the end of October, of the ten milch cows that Dönitz had had in service in the spring only one remained. The effect on U-boat operations was severe. Because resupply by U-tankers was so dangerous, Dönitz avoided it, compelling his
U-boats to break off their operations correspondingly early and destroying his hopes for a formidable offensive in distant waters, far from Allied air cover. In November he abandoned the convoy routes as a theater of operations.

But he returned to the fray the following month. When a patrol line failed to find any ships, he broke it up into subgroups of three boats each in the hope that they would spot targets. It didn’t work. Between mid-December 1943 and the middle of January, they sighted not one of the ten convoys that sailed close to them, and they sank only one merchant ship. At the end of February, Dönitz formed what would be the last wolfpack worthy of the name.
PRUSSIA
’s sixteen submarines sank two small British warships—at a cost of seven U-boats. On March 22 Dönitz ordered another withdrawal. In the first three months of 1944, his U-boats sank only 3 merchantmen in convoy out of 3,360—at a cost of thirty-six submarines. He persisted with his “wonder weapons”—the acoustic torpedo and the snorkel, a valved tube to the surface that enabled a submarine to run on its diesels while under water, increasing its submerged speed and range. But he concentrated now on sinking shipping around the British Isles for the expected invasion of western Europe.