Germany extends unrestricted submarine warfare

It is often said that on 16 November 1939 the commander-in-chief of the German navy, Grand Admiral Erich Raeder, ordered his submarines to sink all Allied merchant ships without warning. The surviving records of the German navy show that this decision had been taken exactly a month earlier. On 16 October Raeder obtained Adolf Hitler’s consent to torpedo without warning every ship identified as British or French, and on 17 October the Naval War Staff (Seekriegsleitung) passed this on to the boats as an order. By mid-November there was nothing left to announce on that score: for a month the U-boats had been waging war without warning against enemy shipping. What November did bring was the next steps in the same policy and, above all, a decision that any further escalation would be introduced quietly, with no formal declaration, so as not to provoke the neutral states, and the United States in particular.

A month earlier: the orders of 16 and 17 October

Germany began the war with instructions requiring its submarines to observe the prize rules: a merchant ship could be stopped and searched, but sunk only once the safety of its crew had been secured. From 24 September the navy removed these restrictions one by one. Dönitz tightened the submarine war first against ships sending radio signals and against French shipping, then against ships sailing without lights, and from 4 October against merchant ships known to be armed.

The turning point came in mid-October. During the night of 13–14 October Kapitänleutnant Günther Prien’s U-47 sank the battleship Royal Oak in Scapa Flow. The success raised the navy greatly in Hitler’s estimation, and Raeder exploited it at once. On 16 October, while reporting in Berlin on Prien’s action, he handed Hitler a memorandum on intensifying the naval war against Britain, dated 15 October. In it the navy argued that the struggle against the British economy demanded “the utmost ruthlessness” and measures that existing international law did not permit. Hitler, who a few days earlier had heard Daladier and Chamberlain reject his peace offer, no longer had any reason to spare the Allies. He agreed that all merchant ships identified as enemy, British or French, could be torpedoed without warning, and that passenger ships sailing in convoy could be too, a certain time after such an intention had been announced. Raeder noted at the same time that passenger ships sailing without lights were already being torpedoed.

The following day, 17 October, the Seekriegsleitung authorised the unrestricted use of weapons against all enemy merchant ships except passenger ships. The justification was that the British were arming their ships (the DEMS programme), had instructed them to report every U-boat by radio and to ram submarines. Since any ship might resist, stopping it in accordance with the prize rules had, in the German view, ceased to apply. On 29 October warships and U-boats were also given the right to attack without warning passenger ships sailing in enemy convoys. On 23 October Hitler further ordered that the whole economic war, from the war on shipping to attacks on enemy industry, be directed centrally by the High Command of the Wehrmacht (OKW), where a separate staff was set up under Admiral Karlgeorg Schuster.

November: step by step, without a proclamation

At the beginning of November Raeder could note that the submarine war against enemy shipping had been intensified “as far as possible”. In his notes for a conversation with Hitler on 1 November he wrote that even passenger ships sailing without lights and in convoy could now be torpedoed without warning, and that all that was missing was the proclamation of a “siege of England”. Such a declaration would have made it possible, after the neutral states had been warned, to sink their ships bound for Britain without warning as well. Raeder also obtained a promise that Hermann Göring’s air force would attack ships sailing in convoy without warning.

Another conference was held on 10 November, in the presence of the chief of the OKW, Wilhelm Keitel. Raeder reported that Germany had so far lost six submarines, in other words as many as the shipyards were due to deliver by the end of 1939. The question of a proclamation came up again. It was considered whether to announce it together with the land offensive in the west, so that the protests of the neutrals would be drowned in the general outrage. Raeder proposed that the declaration be held back for the time being and that the war continue to be intensified gradually. He observed that there was no hurry: the Americans had themselves closed the waters around Britain and France to their own ships. The new American neutrality act, which came into force on 4 November, designated combat zones forbidden to American ships and citizens, which removed the risk of a clash with the most powerful of the neutral states. At the same conference it was decided to allow the City of Flint to return to America.

As the next step Raeder proposed sinking enemy passenger ships without warning, even outside convoys. He argued that they were often heavily armed and carried troops and valuable contraband. Hitler agreed, on condition that the names of the large ships concerned were first made public, together with a statement that they were serving as armed merchant cruisers and troop transports. The step after that, sinking without warning neutral ships known to be carrying contraband, Greek ships for example, was postponed until the attitude of the neutrals changed, for instance once the offensive had begun. The ships of friendly states – Italy, Japan, the Soviet Union and Spain – were still to be spared.

Such was the situation in mid-November, under the date that chronologies usually give. Against British and French shipping the U-boats were already waging war without warning. The prize rules still protected only neutral ships, and it was against these that the Germans were preparing their next steps.

A small fleet and great ambitions

The orders ran ahead of the means. In November 1939 the Kriegsmarine had 57 submarines, some of which were used for training, and according to a summary presented to Hitler only about fifteen were operating against the enemy at any one time. Many of them were small Type II coastal boats laying mines in the North Sea. In the second half of November Dönitz tried for the second time to direct several boats at once against a single convoy. Between 15 and 20 November U-53 made contact several times with a convoy bound for France, but the attack failed, partly because of frequent torpedo malfunctions. The unreliable pistols of German torpedoes were to wreck U-boat attacks for many months to come.

The most dangerous weapon of those weeks was not the torpedo but the mine. Submarines, destroyers and aircraft mined the approaches to British ports with magnetic mines, against which the British as yet had no defence. According to the report Raeder made to Hitler on 22 November, between 8 and 21 November U-boats had sunk 16 ships (9 of them British) totalling some 48,000 GRT, while mines had sunk ships of more than 66,000 GRT. The British government answered the mine war with economic retaliation. On 21 November, after more than ten ships had gone down on mines in three days, among them the Dutch liner Simon Bolivar, Prime Minister Neville Chamberlain announced in the House of Commons that Britain, as in the previous war, would also stop at sea goods of German origin carried in neutral ships. This was put into effect by an Order in Council issued at the end of November.

At the same conference on 22 November Hitler and Raeder agreed on another subterfuge. On 1 December Germany announced by radio that mines had been laid off the east coast of Scotland, although in reality there was no intention of laying any there. From 2 December submarines could sink neutral ships in that area without warning as well, and the losses were to look as though the ships had struck mines. On 29 November U-35 was sunk east of the Shetlands by the British destroyers Kingston, Kashmir and Icarus, and her crew were taken prisoner. On the same day Hitler signed Directive No. 9 on the conduct of the war against the enemy’s economy, which named the defeat of Britain as the condition of victory and a blow at the British economy, above all at its shipping, as the most effective way of achieving it.

Further steps

At the end of November or the beginning of December Dönitz issued Operational Order No. 154 for boats operating off the English coast: do not rescue survivors, do not take them on board and do not concern yourselves with the lifeboats. He later justified this by saying that in guarded coastal waters any attempt at rescue was suicide for the boat. On 30 December Hitler agreed that, within the zone closed by the Americans, ships of states that sold or chartered ships to Britain, above all Greek ones, could be torpedoed without warning, as could neutral ships wherever their loss could be blamed on mines, for example in the Bristol Channel. From January 1940 Germany designated further zones around the British Isles in which submarines could sink any ship without warning, except those of friendly states.

The official proclamation that Raeder had been pressing for since the autumn of 1939 came only on 17 August 1940, after the fall of France. Germany then declared a total blockade of the waters around the British Isles; its limits coincided almost exactly with the combat zone that President Franklin Delano Roosevelt had laid down for American ships in November 1939. By then it was, in practice, a mere formality.

Significance

In 1939 the German navy arrived at unrestricted submarine warfare by a different route from that of 1917. In the First World War Germany had declared it openly, and the declaration had brought the United States into the war. This time Raeder and Hitler, remembering that experience, avoided loud proclamations. They lifted the restrictions one at a time, justified each step by British actions, and sank neutral ships in such a way that the losses could be attributed to mines. Between mid-October and the end of the year all that remained of the old prize rules was the protection of ships of friendly states and caution towards America. The same way of thinking led in 1942 to the “Laconia order”, by which Dönitz forbade the rescue of survivors after the sinking of the British troopship Laconia.

After the war, submarine warfare became one of the charges at the Nuremberg trial. The International Military Tribunal found that Germany had violated the London Protocol of 1936 by sinking neutral ships without warning in declared operational zones. Since the Allies had acted in a similar way, the Americans in the Pacific among them, as Admiral Chester Nimitz confirmed, the tribunal did not base any sentence on this. Raeder was sentenced to life imprisonment for his part in planning and waging a war of aggression and for war crimes, and Karl Dönitz to ten years. For the course of the Battle of the Atlantic, however, something else mattered more: from the autumn of 1939 every ship bound for Britain had to reckon with a torpedo without warning, and the only effective protection became the escorted convoy.