by Clay Blair
Hoffman in Baker carried out two depth-charge attacks, the first astonishingly accurate, the second wide. The charges savaged the stern of U-233, flooding some compartments. She plunged to four hundred feet, out of control and heavy aft. Unable to communicate with the aft section or stabilize the boat, Steen blew all ballast tanks and surfaced to abandon ship and scuttle.
When the U-boat popped up, Hoffman in Baker opened fire with all guns that could bear. The heavy fire decapitated the chief engineer, Wilhelm Bartling, and wounded numerous other Germans who were trying to abandon ship, including the skipper, Steen. The screen commander, George A. Parkinson in Thomas, ordered her skipper, David Kellogg, to ram. Guns blazing, Thomas smashed into U-233 aft of the conning tower, and the U-boat sank swiftly by the stern.
Baker and Thomas fished about half the U-boat crew from the water. Baker picked up ten Germans; Thomas, twenty. The destroyer escorts then transferred the prisoners to Card. Mortally wounded, Steen died and was buried the following day with military ceremony. On July 7, the hunter-killer group put into Boston, its quite specific task accomplished.*
The nineteen patrols (two by U-539) in American waters from January 1 to June 1, 1944, accomplished little beyond tying down Allied forces. Including the “jeep” carrier Block Island, sunk by Krankenhagen in U-549 near Madeira while he was en route to Brazil, these boats destroyed nine ships for about 50,000 tons. In return, seven U-boats failed to return. About 350 submariners manning these boats were lost, eighty-seven of them captured.
FAMILY GRIEF
It will be recalled that Peter Dönitz, the youngest son of Karl Dönitz, was lost in combat in May of 1943 while serving as a watch officer on the new Type VIIC U-954. Hitler had issued a policy stating that if a senior officer such as Dönitz lost a son in battle and had other sons in the military, the latter could withdraw from combat and return to civilian life.* Therefore, Dönitz’s older son, Klaus, a naval officer, entered Tubingen University to pursue studies to qualify as a naval doctor, considered to be a noncombatant position by all nations at war,
Klaus nonetheless kept in close touch with his friends serving in the military. On the eve of his twenty-fourth birthday, May 13, 1944, he visited chums in the 5th Schnell Flotilla at Cherbourg, France. Purely for the adventure, that night he inveigled a ride on the motor torpedo boat S-141, which was to carry out a mission at Selsey, on the English coast.
Two Allied warships intercepted and destroyed S-141. These were the British frigate Stayner and the Free French destroyer La Combattante. The Allies rescued six German survivors, not including Klaus Dönitz. Eventually his body washed ashore in France and it was buried near Amiens.
The loss of this second son doubtless shattered the Dönitz family: Dönitz; his wife, Ingebord; his daughter, Ursula; and her husband, Günther Hessler,† serving as first staff officer at U-boat Control. It was all the more painful inasmuch as Klaus was killed on a lark, rather than on an important combat assignment.
EIGHT
THE GERMAN RUN-UP TO OVERLORD
Adolf Hitler and his military advisers correctly anticipated that the Allied invasion of France would occur in May or early June, but they could not agree on exactly where the landings would come. Fooled by clever Allied deceptions, Hitler and the chiefs of the German Army and Air Force believed that the Allies would strike at the mouth of the Somme River, near Abbeville, about ninety miles north of Paris. Dönitz and other naval strategists believed correctly that the Allied forces would strike farther west in the Bay of the Seine, near Le Havre, a large, well-sheltered seaport about eighty-five miles across the channel from Portsmouth.
The impending invasion of France was not the only major problem confronting Berlin. Likewise fooled by Allied deceptions, Hitler was convinced that the long-awaited invasion of Norway (and/or Denmark) was to take place at or about the same time, probably together with an all-out Soviet summer offensive westward toward Germany. In addition, Allied forces in Italy had at last broken through German defenses and were advancing on German-occupied Rome. This posed a grave threat to the northern industrial regions of German-occupied Italy, which were still working to supply Germany with weapons, including about twenty small (Type XXIII) electro boats under construction at Genoa, intended for operations in the Mediterranean and Black Sea.
Hitler had long insisted that the Arctic and Atlantic U-boat forces were his first line of defense against an Allied invasion in the west. He still held that view in May of 1944. Presumably the large-scale minefields that the Germans had planted in the English Channel constituted the second line of defense and the stout beach defenses (the “Atlantic Wall”) made up the third line of defense. The main line of defense, of course, consisted of the many armored and infantry divisions positioned behind the beaches.
Admiral Dönitz and five of his most loyal senior aides drew the plans for the creation and disposition of this “first line of defense,” the U-boat forces. These men were Hans-Georg von Friedburg, commander in chief, U-boats; Eberhard Godt, commanding U-boat Control; Günter Hessler, Dönitz’s son-in-law; Reinhard Suhren, named commander of U-boats, North (Arctic/Norway), replacing Rudolph Peters; and Hans-Rudolf Rösing, named commander of U-boats, West (France).
The main elements of the plan were as follows:
• Commencing on or about April 1, most of the fifty-odd Type VIIs based in four of the five U-boat bases in France (Brest, St. Nazaire, Lorient, La Pallice) were to cease war patrols. While berthed in protective pens, they were to be fitted with snorkels, search radar, new antiaircraft guns, the latest torpedoes, and other upgrades. When deemed combat ready by Hans Rösing, they were to be assigned to the designated anti-invasion U-boat force, group Landwirt, and be ready in all respects to sail on six hours notice.
• At about the same time, Reinhard Suhren was to create a second anti-invasion force to be berthed in Bergen, where there was a pen, and in small ports in southern Norway. Designated group Mitte (or Central), it was to grow to twenty Type VII U-boats fresh from the building yards in the Baltic. This group, also to be held at six hours notice, would deploy to the North Sea to serve as the first line of defense against an Allied invasion of southern Norway or Denmark. It was commanded by Viktor Schutze, who wore the Ritterkreuz with Oak Leaves.
• Also on about April 1, the Arctic U-boat force, consisting of about thirty Type VIIs deployed in groups on the Murmansk run or in refit, was to prepare to serve as a third anti-invasion force. It was to be berthed in Trondheim, where there was also a pen, Narvik, and in other small ports in northern Norway, all on six-hours notice.
These three anti-invasion forces would comprise about one hundred Type VII U-boats. They could be reinforced rapidly by another twenty or thirty Type VIIs from the Baltic.
Combat experience in 1943 and 1944 had demonstrated beyond doubt that only Type VIIs fitted with snorts could survive against the aircraft and surface ships of the Allied ASW forces. Hence Dönitz decreed that all available snort-equipped VIIs should be posted to France (for group Landwirt) and that as many nonsnort VIIs as possible should be fitted with snorts in Germany, Norway, and France. However, the intense Allied bombing campaigns against U-boat yards in Germany and the French rail system severely disrupted the production of snorts at the source and the flow of snorts to the U-boat bases in France and Norway.
Partly as a consequence of the Allied bombing campaigns, on D day, June 6, 1944, only about one-third of the approximately one hundred Type VII U-boats in Norway and France were equipped with snorts and were combat ready or nearly combat ready: sixteen in France,* eight en route from Norway to France, five in southern Norway, and three in Kiel. Nine VIIs were en route from Norway to France to be fitted with snorts at the Atlantic U-boat bases, but, as will be seen, none of these got there.
Some authors have greatly exaggerated the threat posed to the Allies by these thirty-two combat-ready or nearly combat-ready snort boats. Therefore the limitations of the snort boats of that era bear repeating.
• Most snorts were technically primitive and newly fitted, and not yet fully debugged. Catastrophic breakdowns in the raising and lowering systems and the exhaust and intake mechanisms were more the rule than the exception.
• Contrary to the general impression, snort boats were not “true submersibles.” They did not snort continuously. Most skippers snorted only about four hours each day, principally to charge the batteries. The rest of the time they cruised at 1 to 3 knots on battery power. Hence the average snort boat en route to and from the operating area could only cover about fifty or sixty miles a day. It took a snort boat nearly three weeks to travel one thousand sea miles.
• A snorting U-boat could not use its radio receivers or hydrophones (passive sonar array), and therefore it was “deaf.” Enemy aircraft employing sonobuoys and surface ships with active sonar (“pinging”) could “hear” a snorting U-boat at a time when the “deaf U-boat could not “hear” the enemy.
• A snorting U-boat could rarely use its periscopes. At a snort speed of 5 knots, periscopes tended to vibrate radically, causing the optics to slip out of alignment and, of course, increasing the boat’s visible wake. Except while stopped or making only 1 or 2 knots, a snorting boat was therefore also “blind.”
• Snorts were prone to emit exhaust smoke, visible to the enemy in twilight and daylight.
• Snorts often leaked carbon monoxide into the pressure hull, killing or sickening crewmen.
• When waves dunked the snort, the diesel engines sucked air from inside the pressure hull, causing painful headaches, eye strain, earaches, and other health problems.
• On extended operations, a boat dared not raise its snort merely to ventilate the boat and it had no means of disposing of waste. Hence (as Günter Hessler wrote), “The atmosphere, which was always pretty foul in a snorkel boat, was further polluted by the stench of decaying waste food and other refuse.” The odor was so repulsive that dockyard workers “recoiled from the open hatch” of a returning snort boat.
• Almost without exception, U-boat crews distrusted snorts and hated to use them.
Inasmuch as the Germans had so few combat-ready snort boats and there were disagreements about where the Allies might attempt to land, it was not possible to position them in advance to meet the Allies head on. Hence, upon orders, the boats would have to sail from Biscay ports to the Allied landing area. To cut the reaction time, eleven of the fourteen combat-ready snort boats of Landwirt were positioned at Brest, the U-boat base closest to the English Channel. However, even by the most direct route (roundabout the island of Ushant), it was at least four hundred miles to the Normandy beaches, a snort trip from Brest of seven or eight days.
Once under way, the snort boats would have to deal with Allied amphibious forces protected by heavy ASW forces on extraordinary alert.
Another very serious handicap was the shallow water of the English Channel. Traditionally, of course, submarines shied clear of shallow water inasmuch as it was believed that detection there could be quick and fatal. On the eve of the invasion, however, Dönitz attempted to persuade his skippers of the reverse: that operations in shallow waters might be safer. In shallow waters, he said, enemy sonar was apt to be less efficient due to the distortions in active sonar caused by the nearness of the ocean floor and the inflow of fresh water from rivers, which created thermoclines and variable salinity levels, and to the fact that it was difficult for sonar operators to distinguish between U-boats and the many shipwrecks and the metallic debris littering the channel floor. This was not an easy sell, but German submariners could console themselves with the thought that escape and survival from a submarine wrecked in shallow water might be easier. It might also be possible to swim or paddle a dinghy or life raft to a friendly beach.
No matter how one viewed it, the German plan for employing U-boats as the “first line of defense” against Allied invaders was futile. The snort boats might survive; conceivably some might inflict some minor damage. For the nonsnorts, operations in the channel would be nearly suicidal.
There were no electro boats available to throw against the Allied invaders. Not surprisingly, the production schedule had slipped badly. The first oceangoing Type XXI, (7-2507, was commissioned at Blohm & Voss, Hamburg, on June 27; the first small “duck” Type XXIII, U-2321, at Deutsche Werft, Hamburg, on June 12. The OKM diarist logged on July 30 that “six” Type XXIs had been “delivered” (i.e., commissioned) and that it was hoped a total of 144 would be delivered by the end of 1944. It was also noted that the expected delivery of Type XXIIIs by October 1 had been reduced from forty-three to twenty-three boats and that, owing in part to the loss of eighteen boats under construction in Genoa, it would not be possible to complete eighty-seven Type XXIIIs by the end of 1944.
Delays continued to mount. Actual deliveries of electro boats by the end of 1944: sixty-one Type XXIs and thirty-one Type XXIIIs, all with flaws, none combat ready.*
THE ALLIED RUN-UP TO OVERLORD
On the opposite shores, Allied planners completed final details for Neptune, the amphibious assault phase of Overlord. Responsibility for getting troops safely across the English Channel fell indirectly on the broad back of First Sea Lord Andrew B. Cunningham and directly on the senior Allied naval commander under Eisenhower, Bertram H. Ramsay of the Royal Navy, and his two subordinate admirals, a famous (Victoria Cross) Briton, Philip L. Vian, and an obscure American, Alan G. Kirk, who had been the naval attaché in London under Ambassador Joseph P. war and a task force commander in Torch*
The planners assumed that the most formidable opposition to the landings would be mounted by U-boats. Fortunately for the planners, American and British codebreakers had mastered almost every relevant naval Enigma network and were able to provide remarkably accurate estimates of the numbers of U-boats Neptune might face. These estimates were reflected in the weekly summaries emanating from Rodger Winn’s Submarine Tracking Room during April and May 1944.
Winn’s estimate of Type VIIs, dated May 15, was typical:
45 VIIs in various Biscay ports (group Landwirt)
16 VIIs in southern Norway ports (group Mine)
30 VIIs in northern Norway ports and Arctic waters
91 VIIs total
There were some unknowns and miscalculations:
• The exact number of Type VIIs in France and Norway fitted with snorts was not known and was underestimated.
• The number of new or upgraded Type VIIs (both snorts and nonsnorts) that were ready or nearly ready to sail from the Baltic Sea to Norway or onward to France was not known and was overestimated.
• The number of Type VIIs of the Arctic and Norway forces that were earmarked for transfer to France was not known. Conceivably most of the forty-six VIIs located in the Arctic/Norway area in the May 15 estimate could rush to waters of the British Isles or France to attack the invaders.
The Allies therefore planned for a “worst case” U-boat offensive. They envisioned a total threat of 120 U-boats, with possibly ninety actually in the “invasion area” by June 1. That threat might well include as many as fifty 250-ton “high speed” (40 to 50 knots) “Walter boats “ powered by closed-cycle engines. †In sum, as the Canadian naval historian Marc Milner put it, the Germans might throw every possible U-boat into the battle in a kind of Wagnerian “Gotterdammerung.”
The Allied plan to counter the U-boat threat to Neptune was straightforward and simple in concept. It had two strategic and tactical goals. First, to keep all
U-boats out of the English Channel and St. George’s Channel where Allied forces and logistical backup were to cross from southern England to France, and second, to block the transfer of U-boats from Norway to France. In pursuing these goals, of course, the forces earmarked to carry them out were urged to act offensively and kill as many U-boats as possible.
As to the first task of sealing off the English Channel, it will be recalled that since the beginning of the war the British had maintained a massive minefield across the narrow
est area of the channel at Dover-Cape Gris. This strong and well-tended field in shallow water completely blocked the eastern ingress to the channel. Should a suicidal force of the remaining big German surface warships*(and/or U-boats) attempt to smash through this wall of mines in narrow waters, it would fail absolutely.
The main task for Neptune ASW forces was therefore to tightly seal off the western ingresses to the English Channel and to St. George’s Channel. Anticipating a massive U-boat assault, the Allied planners devoted vast resources to these tasks.
First, air.
The responsibility for putting in place saturation offensive airborne ASW forces in the U-boat blocking areas fell on the shoulders of Sholto Douglas, who had replaced John Slessor as chief of RAF Coastal Command in January 1944. The 19 Group would carry the main air burden.
William Brian Baker’s 19 Group, based mostly in southern England, was increased to twenty-five squadrons. These included four squadrons of the Royal Navy’s Fleet Air Arm and four B-24 squadrons of the U.S. Navy’s Fleet Air Wing 7.†
The rest were RAF squadrons comprised of B-24s, B-17s, Halifaxes, Sunderlands, Wellingtons, Mosquitos, and Beaufighters. Usually an aircraft squadron was composed of fifteen aircraft: twelve combat ready and three in reserve. Thus Baker commanded about 375 aircraft. Most of those planes were fitted with ten or the new, more powerful three-centimeter-wavelength radar. Most carried depth charges or ASW bombs. All had .50 caliber machine guns, many had 20mm cannons, a few had 57mm Tsetse cannons, and some had rockets. Many larger planes carried sonobuoys.
In Baker’s plan, the area to be saturated covered twenty thousand square miles. He divided this space into twelve rectangles, A to K plus Z. The long-range aircraft patrolled an outer barrier (B, E, and F) reaching from the southern coast of Ireland southeastward to the latitude of St. Nazaire (47 degrees, 15 minutes north). The short-range aircraft patrolled two other contiguous and continuous barrier lines (C-D and G-H), east of the outer barrier. The other four zones (I, J, K, and Z) were directly over the English Channel in the invasion area.