The sinking of U-39

On 14 September 1939, in the Atlantic west of the Hebrides, the German submarine U-39 fired torpedoes at the British aircraft carrier HMS Ark Royal, the newest and most valuable ship of her type in the Royal Navy. The torpedoes exploded before they reached their target. Three escorting destroyers, HMS Faulknor, Foxhound and Firedrake, at once attacked the submarine with depth charges and forced her to the surface. The crew abandoned the sinking boat and all 44 men were taken prisoner. U-39 was the first German submarine sunk in the Second World War. Her fate also foreshadowed two problems that were to weigh heavily on the first year of the war at sea: the unreliability of German torpedoes, and the danger to which the British exposed their aircraft carriers by sending them to hunt U-boats.

The boat and her patrol

U-39 was one of the first eight large ocean-going submarines of Type IXA, built by the AG Weser yard in Bremen as part of the rebuilding of the German submarine fleet. The Treaty of Versailles had forbidden Germany to possess submarines, but the naval agreement with Britain of 1935 allowed her to build them, and Plan Z envisaged hundreds. U-39 displaced more than 1,000 tons, had six torpedo tubes and a range of over 10,000 nautical miles. She was commissioned on 10 December 1938 under Kapitänleutnant (Lieutenant Commander) Gerhard Glattes, who remained her only commander.

Together with other boats of the 6th Flotilla, U-39 left Wilhelmshaven on 19 August 1939, when the Commander of U-boats, Karl Dönitz, was sending every ocean-going U-boat ready for action to positions around the British Isles. The boat rounded Scotland to the north and took up station in the Western Approaches to Britain. On 3 September, after Britain declared war, U-boat commanders were ordered to fight merchant ships strictly in accordance with prize rules. Warships, however, could be attacked without restriction. On 10 September U-39 was depth-charged by an unidentified British warship and had to go down to a hundred metres, but came through unscathed.

The British hunting groups

After the sinking of the Athenia on 3 September the British concluded that Germany was waging unrestricted submarine warfare. The Admiralty began to organise convoys, but it lacked escort vessels, and Winston Churchill, First Lord of the Admiralty once again from 3 September, was pressing for offensive action. Hunting groups were therefore formed: an aircraft carrier with several destroyers was to sweep the Western Approaches to the British Isles, while her aircraft searched a wide area for U-boats. Three carriers were assigned to the task: Ark Royal, Courageous and Hermes. Ark Royal, commanded by Captain Arthur Power, operated with an escort of destroyers of the 8th Flotilla north-west of Ireland and Scotland.

The idea had a serious flaw. The carrier aircraft of 1939 were poorly armed against submarines and could seldom destroy a U-boat, while a large carrier, which constantly had to slow down and turn into the wind to fly off or recover her aircraft, became an easy target herself.

The attack on Ark Royal

On the morning of 14 September Ark Royal picked up a distress call from the British freighter Fanad Head, bound from Montreal to Belfast. The ship had been stopped some two hundred nautical miles from the carrier by U-30, the same boat that eleven days earlier had torpedoed the Athenia. The carrier turned into the wind and began to fly off her aircraft. At that moment she passed in front of U-39.

Glattes fired two torpedoes at the carrier (some accounts speak of three) from a range of about 800 metres. Lookouts on Ark Royal spotted their tracks, and the ship turned towards them, presenting a narrower target. In the event, the torpedoes never reached her: they exploded prematurely, astern of the carrier. Their magnetic pistols had failed. These were supposed to detonate the charge beneath the target’s keel in response to its magnetic field, but in practice they went off too early or not at all.

The explosions gave away the U-boat’s position. The destroyers Faulknor, Foxhound and Firedrake found her with their sonar (ASDIC) and began dropping depth charges. The damaged boat surfaced a few seconds after one of the patterns dropped by Firedrake. The Germans leapt into the water, and U-39 sank at 58°32′ N, 11°49′ W. The British picked up the entire crew: Foxhound took 25 men, Faulknor eleven and Firedrake eight. No one was killed.

Meanwhile aircraft from Ark Royal had reached the Fanad Head. Three Blackburn Skua dive bombers attacked U-30, which had managed to submerge. The anti-submarine bombs were dropped from such a low altitude that their explosions damaged two of the Skuas, and both fell into the sea. Their gunners drowned, and the pilots were pulled from the water by U-30. Fritz-Julius Lemp’s boat sank the Fanad Head and sailed away, carrying them to Germany as the first prisoners from the Fleet Air Arm. The same day thus brought the British their first victory over a U-boat and showed how poorly prepared their naval aviation was for fighting submarines.

The silence of U-39

The prisoners from U-39 were taken to Scotland and then to London. Some of the interrogations were conducted in the Tower of London. They were later sent to prisoner-of-war camps in Britain and then to Canada, where they spent the rest of the war. The British announced their success quickly and with relish. In Germany nothing was known of the boat’s fate for several days. On 22 September the Naval War Staff (Seekriegsleitung) noted in its war diary that U-39 had failed to report her position despite repeated calls and should already have returned to base, which gave cause for “grave concern”. A clue was found in a British radio announcement that the first prisoners from the German navy had been brought to one of the London railway stations.

A few days after the attack Churchill visited Ark Royal at the Loch Ewe anchorage and inspected her crew. The sinking of U-39 raised morale in Britain, which in the first weeks of the war was losing one ship after another at sea and had, moreover, to reckon with the German mines being laid off her coasts.

Significance

The success proved illusory. Only three days later, on 17 September, U-29 sank the carrier Courageous in the Western Approaches, and more than five hundred men went down with her. The Admiralty then decided that risking carriers in the pursuit of U-boats was too dangerous and withdrew them from the hunting groups. The second U-boat sinking was not long in coming: on 20 September the destroyers Forester and Fortune sank U-27 north of Scotland. By the end of 1939 the Germans had lost nine submarines, almost a sixth of the fleet with which they had entered the war.

U-39’s failed attack was also one of the first signs of the German torpedo crisis. The magnetic pistol, of which the Kriegsmarine command was very proud, failed in practice: torpedoes exploded prematurely or passed beneath their targets, while those fitted with contact pistols often did not explode at all because they ran too deep. Reports of duds multiplied throughout the autumn. On 30 October 1939 U-56 hit the battleship HMS Nelson with torpedoes that failed to explode. Dönitz noted in his diary at the time that the commanders’ confidence in their torpedoes was bound to weaken. The crisis reached its height in the spring of 1940, during the Norwegian campaign, when dozens of attacks on British warships and transports came to nothing. Only after that campaign were most of the defects eliminated, and from the summer of 1940 German torpedoes were regarded as reliable. Had they worked in September 1939, Ark Royal would have gone down in the second week of the war rather than in November 1941, when U-81 sank her in the Mediterranean.