Turning the Tide: FDR and the Battle of the Atlantic, March 18, 1943

by Kevin Thomas, Special Events Coordinator

Franklin D. Roosevelt delivers his Christmas message on the radio from his study in the FDR Library in Hyde Park, New York, December 24, 1943. NPx 61-71.

Lend-Lease is one of Franklin Roosevelt’s most remarkable and vital achievements in the formation of the anti-Hitler alliance

–        Soviet Premier Joseph Stalin, at the Tripartite Dinner during the Yalta Conference, February 8, 1945

Stalin was correct. The massive economic effort of the United States was one of the key factors that tipped the balance overwhelmingly in favor of the Allied Powers in World War II. Tremendous amounts of vehicles, supplies, and food, through the Lend-Lease Program, made their way across the globe to other allied nations – particularly to the two primary US partners – the United Kingdom and the Soviet Union. This assistance, which began even before the US officially entered the war itself, kept the Allied resistance against the Axis forces energized.

In the Atlantic Ocean, where much of the supplies needed to travel, the task was very difficult. The ships tasked to transport the supplies needed to cross an ocean infested with Nazi submarines. These silent hunters, known as U-Boats, would prey on unprotected merchant vessels, and even proved a difficult foe at times amongst armed convoys.

The United States began armed escorts of merchant vessel convoys (ships traveling in groups for safety), even before entering the war in December, 1941. After the attack on Pearl Harbor, the United States was forced to shift a large portion of its attention to the Pacific Ocean, leaving the efforts in the Atlantic strained. As early as January, 1942, German U-Boat forces entered US waters and at times, seemed to torpedo and shell merchant vessels at will – both on the open water and in what would be considered safe harbors such as New York City, and Mobile, Alabama.

Known as the Battle of the Atlantic, this harrowing period of naval combat has recently been brought to life in the film release, Greyhound.

The U.S. oiler SS Pennsylvania Sun torpedoed by the German submarine U-571 on 15 July 1942, about 200 km west of Key West, Florida (USA). Pennsylvania Sun was saved and returned to service in 1943. Source: Library of Congress

By 1943, the United States, the United Kingdom (UK), and Canada, had varying degrees of success in keeping the merchant fleets operating with a continuous flow of supplies. This was in spite of continuous losses at the hands of the U-Boats. Fortunately for the allies, shipping losses did not seriously outstrip replacements. However, the see-saw battle hampered the flow of supplies.

There were many things at stake. Great Britain continued to need US and Canadian food to keep its armed forces and its citizens fed. Public moral – a major component of successful warfare in the modern age – was also effected by the sinking of vessels. A constant string of bad news – even if these vessels, supplies, and manpower losses were replaceable – doesn’t help any war effort. Perhaps most importantly, the buildup for the invasion of Northwest Europe (later known as D-Day) required a massive amount of troops, supplies, vehicles, and ships. Any slowdown in the supply chain due to submarine attacks, would further delay its launch – with potentially devastating consequences for the war itself.

Something had to be done.

Franklin D. Roosevelt fishing with Winston Churchill at Shangri-La, May 1943. NPx 47-96:1535.

On March 18, 1943, UK Prime Minister, Winston Churchill, sent a message to US President Franklin D. Roosevelt, outlining the difficult situation facing the two nations in maintaining all their commitments and fighting off the U-Boat menace.

It was proving difficult, according to the Prime Minister, to provide protection for convoys of supplies to the Soviet Union, as well as to convoys in the Atlantic. The escort abilities of the Royal Navy were thin, and he recommended a halt of convoys to the Soviet Union until after the Invasion of Sicily (Operation HUSKY) was underway later that summer. The British had recently lost 17 ships in two convoys, over two days’ time. By month’s end, 82 Allied ships would be lost in the Atlantic, against 12 German U-Boats destroyed. The scale was beginning to move away from the Allies once again.  The Prime Minister did add a silver lining – that he foresaw the eventual arrival of Allied aircraft and surface ship reinforcements in later weeks after the allied operations in Sicily and North Africa freed them for use in the Atlantic. This would help considerably, but that was some time in the future. There was a threat now.

All of this news would have angered and distressed Joseph Stalin, which is why Churchill wished to avoid telling the Soviet Premier for the moment. While we do not know what Roosevelt said upon receiving this ominous note, we do know what he decided to do about it.

President Roosevelt drafted a memo, that same day, which became a rare instance of direct intervention in the military operations of his commanders. Roosevelt tended to let his commanders run their own strategy and tried to avoid direct orders as Commander in Chief. This prerogative was also employed when he opted for an invasion of North Africa against the wishes of his top military officers.

Roosevelt, Churchill, and Naval commanders of both the Allied and Axis forces knew that the deadliest threat to German U-Boats was aircraft. Aircraft were nearly immune to attack from U-Boats (occasionally anti-aircraft guns could be deployed by U-Boats against them), and when equipped with radar, could spot German or Italian submarines long before their unsuspecting crews onboard knew the plane was there. Aircraft, such as B-24 bombers, launched from land, could mount quick moving patrols across large swaths of the Atlantic, and could warn convoys of the threat. They could also alert patrols of surface ships such as destroyers to intercept the U-Boats; and if equipped with measures such as depth charges, could attack the U-Boats on their own. Allied aircraft and bombers had been operating with success against U-Boats in the Atlantic for some time.

In his memo of March 18 to General George C. Marshall and Admiral Ernest King, President Roosevelt turned back US attention to anti-submarine operations in the Atlantic and made them an immediate short term priority. Any losses to shipping, he stated, threatened other long term strategic goals, including the build-up of forces for the invasion of occupied France (Operation BOLERO). An antidote – more long range B-24 bombers; many of which were located in the Pacific Theater. Those already in use, were found to be effective at closing the “Mid-Atlantic Gap” – the area in the central portion of the ocean previously unreachable by other land based aircraft. Roosevelt asked that as many of these bombers be shifted to the Atlantic as practicable, and as soon as possible.

This order, in concert with other newly developed and improved technologies – particularly aircraft carried radar, the Leigh Light, and escort-class destroyers – quickly turned the tide in the Battle of the Atlantic. By the end of May, just two months later, the Germans suspended U-Boat operations in the North Atlantic. Their losses had become drastic, and were irreplaceable. They were quickly failing to disrupt allied shipping at all. They would not recover the losses suffered in the spring of 1943 – German Admiral Donitz admitted that Germany had lost the Battle of the Atlantic.

This Consolidated B-24D-30-CO “Liberator” heavy bomber, serial number 42-40127, named “First Sergeant” was the assembly ship for the 458th Bombardment Group (Heavy).  Archivist note:  Assembly ships were painted in dazzling patterns to facilitate visibility in the air. NPx 63-343(B)

Consequently, the allies were able to build up their invasion forces in the United Kingdom for the planned invasion in Normandy, which would come one year later. The rate of this supply would increase many-fold, as the threat of attack on convoys decreased, and the increased rate of Allied production of shipping allowed even greater movement of tonnage across the ocean. The anxiety of a delay to Allied offensive operations in Europe disappeared, and attention could now focus on carrying out the invasion – which brought its own set of high stakes decision making.

The victory in the Battle of the Atlantic was a significant moment in the Allied defeat of the Axis Forces in Europe. It arguably ended the German strategic initiative on the seas. Later that same July, the Soviet Union would defeat a massive German offensive near the Soviet city of Kursk. That battle would effectively end German strategic initiative on land. For the remainder of the war, because of these two major defeats, Germany would be fighting the war on the defensive – and ultimately, defeat.

Both the Churchill message, and the Roosevelt memo, of March 18, 1943, can be found in the holdings of the Franklin D. Roosevelt Presidential Library.