Marc Milner - Battle of the Atlantic

1, September 1939March 1940

2, April 1940March 1941

3, AprilDecember 1941

4, JanuarySeptember 1942

5, JulyDecember 1942

6, JanuaryMay 1943

7, JuneDecember 1943

8, JanuaryAugust 1944

9
September 1944May 1945

T he Atlantic lay at the heart of the Second World War. The Anglo-French alliance of September 1939 was a global maritime one, as both great powers drew strength from their vast possessions (and in the British case recently independent Dominions) and trading networks overseas. France, of course, was vulnerable to a land and air assault by Germany, and succumbed in MayJune 1940. But Britain and her Commonwealth and Empire lay tantalisingly out of reach for the panzer armies of Nazi Germany in 1940, and so they remained despite attempts to force Britain itself into capitulation.

However, it was not enough for the western Allies simply to survive. The manpower and sinews of war and ultimate Allied victory in 1945 had to be brought to Britain by sea and, equally importantly, men and materiel had to be re-shipped from Britain to develop and sustain military operations in theatres around the globe. None of this was possible without unfettered use of the Atlantic. Indeed, the maritime nature of the western Allies war effort only increased as the United States became involved. It is difficult to imagine how the industrial and manpower resources of the Great Republic could have been applied decisively in Europe from the landings in Italy and France, to logistical support for the campaigns ashore without a secure Atlantic crossing to the advanced base of the British Isles. It is true that many aircraft were flown to theatres abroad, but even the massive air offensive against Nazi Germany depended, in the end, on command of the Atlantic.

This book is about the battle for that crucial theatre. It builds on decades of primary research and familiarity with the secondary sources to present a new vision of the Battle of the Atlantic. It suggests a revised understanding of the limits on German ability to win the Atlantic war. It draws long-neglected players, primarily Canadian and American, into a revamped narrative. It illuminates familiar events in new ways. And it integrates significant new material on the post1943 era into the story of the Atlantic war.

The Afterword to the first edition indicated that much work remains to be done on this, the longest, most complex and most fascinating campaign of the Second World War. That situation has not changed appreciably since the first edition of Battle of the Atlantic appeared. I hope that this one will encourage a new generation of scholars to take up that challenge.

Marc Milner

February, 2011

T he Second World War was only a few hours old when a look-out on the conning tower of the German submarine U-30, cruising 600km north-west of Ireland, spotted a large vessel on the horizon. The U-boats twenty-six-year-old captain, Lieutenant Fritz Julius Lemp, spent the next two-and-a-half hours working around ahead of the contact so that he could make a close inspection from the safety of periscope depth. What Lemp saw through the lens in the gathering twilight was a small liner, running a zigzag course without lights and apparently armed. Such a target could only be an Armed Merchant Cruiser (AMC), typically a small passenger ship equipped with guns, manned by a naval crew, commissioned as a warship and used for patrolling. Lemp moved U-30 into firing position and, forty minutes later at 19:40 hours Greenwich Mean Time on 3 September 1939, he fired two torpedoes. Thus began the Battle of the Atlantic, the longest campaign of the Second World War and the longest and most complex submarine war in history.

The idea that German submarines might attack shipping in the North Atlantic was, of course, hardly unexpected in 1939. After all, they had done so with remarkable success during the First World War and in 1917 had brought Britain perilously close to ruin. That crisis was precipitated by a combination of wishful thinking, poor organisation and planning, and a lack of proper anti-submarine equipment primarily a good underwater locating device. In the early years of the First World War, no one really believed that the Germans would launch a submarine campaign against unarmed merchant vessels. Submarines were ill-suited to capturing enemy vessels, or to the obligations under international law to inspect cargoes and ensure crew safety prior to sinking a ship. Simply sinking ships on sight and sending cargoes and crews alike to a watery grave not only contravened international law, but such wanton destruction of property and the lives of civilians had never occurred in maritime war before. Indeed, even the Germans were loath to undertake a submarine campaign against merchant shipping, though it was the only way to strike a blow at the Allies through their largely impenetrable surface blockade. Every time there was a mistake, like the sinking of the liner Lusitania in May 1915 or the Sussex a year later, howls of international condemnation followed especially from the worlds most powerful neutral country, the United States.

So between 1914 and 1917, the expectation that the Germans would not slip outside the bounds of acceptable behaviour albeit stretched and modified by the new horrors of total war governed British attitudes towards trade defence and anti-submarine warfare. Losses to shipping were sustainable, while defence rested on protected lanes swarming with patrol vessels and aircraft, dispersion of ships along individual routes on the high seas and, ultimately, on keeping ships in port. German U-boats wisely stayed out of the heavily patrolled zones, operating offshore in individual patrol areas through which a solitary vessel sooner or later because of the Allied practice of dispersion was bound to pass. In the early years, it was this that gave the submarine the advantage, since it was heavily armed and faster than the average merchant vessel. Confronted by this lethal spectre from the deep, merchant seamen usually took to their boats, leaving the U-boat crew to the leisurely business of sinking the ship by gunfire or scuttling charges. As merchant ships began to fit guns, however, running gun battles developed and wary submariners grew more and more inclined to fire torpedoes first and ask questions later. This became increasingly so when the British sent disguised and heavily armed Q ships to sea with the express purpose of ambushing submarines on the surface as they approached. In fact, until 1917 the principal weapons in both submarine and anti-submarine warfare were guns, which says a great deal about the power of international opinion and the nature of the fighting at sea.

All that changed in February 1917, when the Germans, out of sheer frustration at their failure on all fronts and an earnest desire to win the war, declared unrestricted submarine warfare against Allied merchant shipping. With U-boats now free to simply torpedo without warning any ship in the war zone around the British Isles, losses to Allied shipping skyrocketed and through the spring of 1917 the new practice looked like being a success. By April, Britain was on the brink of crisis. Ships and cargoes were going down much faster than they could be replaced, and the existing defensive system of high seas dispersion and safe lanes inshore no longer worked. It appeared that the only way to preserve shipping was to keep it in port. What saved the situation in 1917 was the decision taken at the end of April to put all ocean-going shipping into escorted convoys.

Convoys were an ancient idea. They had been used successfully throughout the great age of sail, and were used extensively during the First World War for troopships and other vital traffic. Indeed, by early 1917 heavy losses in routine merchant traffic to Norway and Holland had been virtually eliminated by the adoption of convoys. Even the crucial coal traffic to France was convoyed without loss. Extending this system to ocean shipping brought immediate results: losses went down steadily and shipping moved. It was the new convoy system, rather than anything technological or tactical, which defeated the 1917 U-boat campaign. Gathering shipping into compact, escorted groups cleared the ocean of easy, individual targets. This made target location for lone U-boats operating off-shore extremely difficult. And then when they did find a target, it was now a mass of ships heavily escorted by destroyers and, increasingly, long-range patrol aircraft: a daunting task for submariners used to handling a single lumbering merchant vessel.