Hans Geisler

Hans Ferdinand Geisler was an officer of the Imperial Navy who in the inter-war years helped to build up the German naval aviation forbidden by the Treaty of Versailles, and in 1933 transferred to the nascent Luftwaffe. During the Second World War he commanded X Air Corps (X. Fliegerkorps) for three years, a formation designed to fight the enemy’s fleet and shipping. His aircraft attacked British warships in the North Sea, supported the invasion of Norway and, in January 1941, after being transferred to Sicily, severely damaged the aircraft carrier Illustrious and began the German bombing of Malta. Geisler was not among the best-known Luftwaffe generals, but he was one of the architects of the German doctrine of attacking ships from the air, and his corps showed the Royal Navy that a fleet without fighter cover is defenceless against land-based air power.

An officer of the Imperial Navy

He was born on 19 April 1891 in Hanover. On 1 April 1909 he joined the Kaiserliche Marine, the Imperial German Navy, as a cadet. He studied at the naval school at Mürwik near Flensburg, made a training cruise in the cruiser Hertha, and in 1910 became a midshipman (Fähnrich zur See). In the autumn of 1911 he was posted to the High Seas Fleet battleship Nassau, and in 1912 he was commissioned as a Leutnant zur See. The outbreak of the First World War found him in Nassau.

In May 1915, by then an Oberleutnant zur See, Geisler went ashore and transferred to naval aviation. He served as an observer in seaplane units that carried out reconnaissance over the North Sea and the Baltic, hunted submarines and covered fleet movements. From October 1917 he was a staff officer for special duties to the head of naval aviation, Captain Heinrich Otto Kranzbühler, in Berlin. For his service he received both classes of the Iron Cross. The experience of these years – combining a seaman’s knowledge with the capabilities of the aeroplane – set the course of his entire later career.

In the Reichsmarine

The Treaty of Versailles forbade Germany to possess military aviation, naval aviation included. Geisler stayed in the reduced Reichsmarine, but over the following years many of his posts were connected with the aviation that the navy kept in secret. In 1919–1920 he was an observer and then acting commander of the seaplane unit at Holtenau near Kiel. He was then an adjutant at the Baltic Naval Station, in 1921–1922 he commanded the minesweeper M 82, and in 1925 he was the aviation officer on the staff of the Baltic Naval Station. He completed the secret staff officer training (Führergehilfenausbildung) that replaced the war academy banned by the treaty, and in 1926–1928 worked in the fleet department of the naval command.

From October 1928 to October 1932 he headed an establishment at Warnemünde which, under the name of Funk-Versuchs-Kommando, a radio communications testing detachment, in fact also handled training and trials in naval aviation. Serving under him there was a young officer, Martin Harlinghausen, later his corps chief of staff and one of the best German specialists in attacking ships from the air. From October 1932 to March 1933 Geisler was first officer of the old battleship Schleswig-Holstein, the same ship that in September 1939 shelled the Westerplatte. On 1 January 1933 he was promoted to Fregattenkapitän (Commander).

From the navy to the Luftwaffe

On 1 September 1933, a few months after Hitler came to power, Geisler transferred to the military aviation being built in secret, which was revealed in 1935 as the Luftwaffe. In Hermann Göring’s Reich Air Ministry he headed the training department; in 1934 he was made a colonel (Oberst), and from 1 October 1935 to March 1939 he was commander of naval air forces (Führer der Marineluftstreitkräfte). It was a difficult post, because a bitter dispute was being fought over aviation at sea between Göring, who wanted everything that flew under his control, and the navy’s commander, Admiral Erich Raeder, who demanded naval aviation of his own. The dispute ended in 1939 with a compromise favourable to the Luftwaffe: the navy was left mainly with reconnaissance aircraft, while the anti-shipping bombers came under the air force. In 1937 Geisler became a Generalmajor, and on 1 April 1939 a Generalleutnant.

Commander of X Air Corps

In the summer of 1939 Geisler was put in charge of a special staff attached to Luftflotte 2, which was to prepare the air war against the British fleet. After the outbreak of war the staff was converted on 5 September 1939 into the 10th Air Division, and on 2 October into X Air Corps, with its headquarters at Blankenese near Hamburg. Harlinghausen became chief of staff. The corps was a headquarters to which bomber and fighter wings were assigned according to the task; its core consisted of the bomber wings KG 26, flying Heinkel He 111s, and KG 30, with the new Junkers Ju 88s.

The first months of the war revealed both the possibilities and the weaknesses of the new formation. On 16 October 1939 Ju 88s of KG 30 attacked warships in the Firth of Forth, and the next day Scapa Flow – these were the Luftwaffe’s first raids on Britain. During the winter the corps’ aircraft attacked merchant ships and fishing boats in the North Sea. On 22 February 1940, because of a disastrous lack of communication between the Luftwaffe and the navy, an He 111 of KG 26 attacked German destroyers carrying out Operation Wikinger: Leberecht Maass and Max Schultz sank, hit by bombs and by mines, and more than five hundred sailors were killed. On 16 March 1940 the corps’ bombers attacked Scapa Flow, killing on Orkney the first British civilian to die in an air raid on land.

At the beginning of March 1940 Geisler and Harlinghausen learned in Berlin of the planned invasion of Denmark and Norway. The corps was given all the air units earmarked for it, some thousand aircraft in all, including several hundred Ju 52 transports, which carried paratroops and infantry to the captured airfields of Oslo-Fornebu and Stavanger-Sola. On 9 April 1940 Geisler’s bombers attacked the British Home Fleet off the Norwegian coast, sank the destroyer HMS Gurkha and hit the battleship Rodney. The next day Geisler’s name was mentioned in the Wehrmacht communiqué, and on 4 May he received the Knight’s Cross of the Iron Cross. During the Norwegian campaign it was air power that allowed the weaker Kriegsmarine to hold on to its gains: the British fleet controlled the sea but could not remain for long within range of the German bombers. The price was heavy losses among the corps’ airmen.

After the campaign the corps remained in Norway as the main striking force of General Hans-Jürgen Stumpff’s Luftflotte 5. From June to September 1940 Geisler was at the same time acting head of training at the Air Ministry, and the corps was commanded in his place by General Bernhard Kühl. On 19 July 1940, in the great round of promotions after the victory over France, Geisler was made General der Flieger. On 15 August 1940 aircraft from Norway and Denmark attacked north-east England, expecting to find it undefended. The raid ended in defeat and heavy losses, and the day went down in history as the Luftwaffe’s “Black Thursday”; Luftflotte 5 made no further daylight raids on Britain.

Sicily and Malta

In the autumn of 1940 the situation in the Mediterranean forced Hitler to come to Italy’s aid. After the attack on Taranto, the defeats in Greece and the British offensive in Egypt, the Italians asked the Germans for help, and in December the decision was taken to transfer X Air Corps from Norway to Sicily and southern Italy. The corps, whose first units arrived at the turn of the year, numbered several hundred aircraft by mid-January 1941: Ju 88 bombers at Catania, Ju 87 dive-bombers at Trapani, He 111s adapted to drop torpedoes, and Bf 110 heavy fighters. It had three tasks: to cover the Italian convoys to Libya, to paralyse Malta and to close the Strait of Sicily to the British fleet.

The first blow was the greatest success of Geisler’s career. On 10 January 1941, during the British convoy operation Excess, his corps’ Stukas hit the aircraft carrier Illustrious with six bombs, killing 126 of her crew, and the next day they sank the cruiser Southampton. Somewhat ironically, the same ship had been the target of the first attack by Geisler’s Ju 88s over the Firth of Forth in October 1939, when she suffered minor damage. For the next two weeks the aircraft of X Air Corps bombed Grand Harbour in Malta, where the damaged carrier lay, and the island’s airfields, destroying houses in the Three Cities and killing dozens of civilians. Illustrious nevertheless managed to escape to Alexandria on 23 January, and losses among the Stukas, diving into the anti-aircraft barrage, were severe.

From the end of January 1941 the corps’ He 111s dropped mines into the Suez Canal and halted shipping for many days. One such flight, against convoys in the Great Bitter Lake, ended with Harlinghausen himself making a forced landing in the desert; he was found a few days later. From February to April the corps carried out systematic raids on Malta, and its Bf 109 fighters gained the upper hand over the British Hurricanes. In March British surface ships and bombers stopped using the island as a base for a time, and Italian convoys safely carried General Erwin Rommel’s Afrika Korps to Tripoli. The success was not complete, however: Malta was not permanently neutralised, and at the end of March the British routed the Italian fleet at the Battle of Cape Matapan, beyond the corps’ reach.

Greece and retirement

In the spring of 1941 a large part of X Air Corps’ strength was moved to the Balkan campaign, and after the occupation of Greece, in June 1941, the corps moved there permanently. Geisler’s headquarters was henceforth in Athens, and his aircraft flew from airfields in Greece, on Crete and on Rhodes. In the Battle of Crete in May 1941, however, the main role was played by the neighbouring VIII Air Corps under General Wolfram von Richthofen. Over the following year Geisler’s corps attacked British convoys to besieged Tobruk and to Malta, shipping off the coasts of Egypt and Palestine, and the Suez Canal, and in June 1942 its bombers helped to turn back the British convoy of Operation Vigorous. The eastern Mediterranean was, however, a secondary theatre for the Luftwaffe, and the corps’ strength gradually dwindled in favour of the Eastern Front.

On 31 August 1942 Geisler handed over command of the corps to General Otto Hoffmann von Waldau and was placed at the disposal of the Air Ministry. On 20 October 1942 he received the German Cross in Gold, and on 31 October he retired. He was not recalled to service for the rest of the war and was never taken prisoner. He died on 25 June 1966 in Freiburg im Breisgau.

Significance

Geisler belonged to the generation of naval officers who moved to the Luftwaffe and brought to it a knowledge of war at sea that most of Göring’s airmen lacked. His corps was the first formation in the Luftwaffe designed exclusively to fight warships and shipping. In Norway in the spring of 1940 and in the Mediterranean in January 1941 it demonstrated what the Royal Navy was learning the hard way: that warships operating within range of strong land-based air power, without fighter cover of their own, suffer heavy losses and can be driven out of narrow seas. The attack on Illustrious was at the same time proof of the limits of this weapon – the armoured carrier survived, and Malta, though bombed for two more years, did not fall. The dispute over naval aviation between Göring and Raeder and the constant shifting of aircraft to other fronts meant that Germany never built the strong naval air arm that a war against Britain would have required. In the memory of the Maltese and of Royal Navy sailors, Geisler’s corps left behind the January “Illustrious Blitz”, the first of the great ordeals the island was to endure.