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— CH. 1 · INTRODUCTION —

Kanalkampf

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  • Kanalkampf is the German word for Channel Battle, and it names a campaign that unfolded over the English Channel in the summer of 1940 when the Luftwaffe turned its attention to the convoys keeping Britain supplied. The Battle of France had ended with an Allied defeat by the 25th of June. Britain refused peace terms. On the 16th of July, Adolf Hitler issued Directive 16 ordering preparations for an invasion of Britain under the codename Operation Sea Lion. To pull that off, Germany needed control of the skies over southern England. The Luftwaffe had a task: destroy the Royal Air Force and keep the Royal Navy away from the invasion fleet.

    The solution the Germans chose was to attack the convoys threading through the Channel. Sink enough ships, draw out enough British fighters, and Fighter Command would be exhausted before the main offensive even began. What followed was a grinding, costly, and often overlooked opening phase of the Battle of Britain. Who held the Channel? What did the coal convoys have to do with it? And did the Luftwaffe actually succeed? Those are the questions this documentary will answer.

  • On the 8th of July, only 20 of the 84 railway tanks carrying aviation fuel had reached the main German depot at Le Mans. That single supply snapshot captures why the Kanalkampf began so slowly. After the Armistice of the 22nd of June 1940, the Luftwaffe had to relocate its air fleets in a third major operational move within two months, pushing Luftflotte 2 and Luftflotte 3 into northern France and Belgium, stretching along the English Channel coast.

    Repairing French and Belgian infrastructure consumed weeks. Bridges had to be rebuilt to supply forward bases. Short-range dive bombers and fighters were sent to airfields that lacked electricity and running water for the crews. The Transportgruppen, the transport formations meant to keep everything moving, could barely keep their own units running. Senior staff officers, meanwhile, were distracted by victory celebrations in Paris. Hermann Göring himself was promoted to Reichsmarschall during this period. The result was that about forty days passed after the French surrender before the Luftwaffe could mount a serious assault on Britain.

    By the 17th of July, the two air fleets had finally reached their intended strength, with roughly 1,200 medium bombers, 280 dive bombers, 760 single-engine fighters, and 220 twin-engine fighters positioned for operations against southern England and the Midlands. Luftflotte 5 in Norway, with 130 medium bombers and 30 twin-engine fighters, added indirect pressure by tying down RAF fighters in the north.

  • Reichsmarschall Hermann Göring despised the German Navy and its commander, Grossadmiral Erich Raeder. In his view, Raeder and the navy represented exactly the class of German society that National Socialism had pledged to sweep away. That personal loathing had a direct operational consequence: Göring refused to let the Luftwaffe cooperate with the Kriegsmarine in the war against British shipping.

    All directives from the Oberkommando der Wehrmacht stated that attacks on warships and shipping must come second to military objectives. The OKW did not revise this view until February 1941. Göring's own directive of the 30th of June made his priority plain: strike the RAF, establish air superiority, and perhaps persuade the Churchill government to negotiate. He even skipped Hitler's the 31st of July conference in Berlin where Operation Sea Lion was outlined, and he ignored multiple summonses to inter-service cooperation meetings.

    The result was that the Luftwaffe's Channel operations were never a coherent naval blockade. Operations against British sea communications, which a formal blockade from the 18th of July required, were only ever a half-measure. Hans Jeschonnek, Chief of the Luftwaffe General Staff, ordered attacks on coastal shipping on the 11th of July as a prelude to the main air battle, but the two Luftflotte commanders, Hugo Sperrle and Albert Kesselring, had already begun coastal operations on their own initiative simply because OKL's indecision had left them with little else to do.

  • British power stations ran on coal from Wales, Northumberland, and Yorkshire, as did the railways, manufacturing industry, and shipbuilding. South coast ports needed 40,000 long tons of coal a week, and land transport could not pick up the slack. The convoys were not optional.

    The English Channel presented a brutal tactical problem. Between the English, French, and Dutch coasts, the Channel stretched roughly 400 miles long, 110 miles at its widest, and a mere 22 miles between Dover and Calais. The seas were full of shoals, sandbars, shipwrecks, and minefields laid by both sides, sometimes forcing ships into single file. Coal convoys sailed both directions: the CE convoys assembled at Glasgow and came south past Land's End; CW convoys returned westward. A full CE convoy typically carried an escort of two destroyers and six armed merchant trawlers, with additional escort ships from Plymouth, Portland, and Portsmouth commands joining and relieving each other along the route.

    Convoy code-names were assigned to allow air cover to be summoned by radio. The list included names like Bread, Booty, Peewit, Pilot, Bacon, and Topaz. Merchant ships could not broadcast these names, which were reserved for escorts and their senior officer. Peewit was used for convoys on the 21st of July and the 11th of September; Booty appeared on the 25th and the 30th of July, the 11th of August, and the 8th and the 21st of November.

    Coastal radar offered little advance warning against attacks from nearby French airfields. German aircraft could strike and withdraw before British fighters could intercept. Standing patrols over convoys could compensate but exhausted pilots and handed the tactical initiative to the Germans.

  • At 08:15 on the 4th of July, Junkers Ju 87 Stukas arrived over Portland harbour with no RAF fighters in sight. Their target was the anti-aircraft ship Foylebank, an armed merchant vessel fitted with four twin four-inch high-angle guns and multiple Pom-Pom guns. The gunners did not have time to man their weapons before 104 bombs fell, many hitting the ship. Foylebank's tender was struck and sank immediately. A total of 176 sailors were killed or later died of wounds.

    The same attack sank the Silverdial and damaged three merchantmen: East Wales at 4,358 gross registered tons, William Wilberforce at 5,004 GRT, and City of Melbourne at 6,630 GRT. One Ju 87 was shot down by Foylebank's gunners, its pilot and gunner posted missing.

    Later that same day, a second convoy, OA 178, was intercepted southwest of Portland. The SS Dallas City, at 4,952 GRT, was bombed and engulfed in flames, colliding with the SS Flimston, also hit. The two ships took fifteen minutes to disengage. Dallas City later sank. The Dutch ship Deucalion, at 1,796 GRT, went down with only 27 survivors. Two more ships, Kolga and Britsum, were sunk.

    Winston Churchill submitted an "Action This Day" memorandum to the Admiralty that same day, asking on a single sheet of paper what arrangements were being made for Channel convoys given German forces now held the entire Channel coast. Vice Admiral Max Horton, the Dover Commander-in-Chief, described the day as a disgrace. Churchill demanded Fighter Command do more to protect Channel shipping. It was, as one account recorded, the worst loss of life inflicted on British military personnel based in Britain up to that point in the war.

  • No 141 Squadron's Boulton Paul Defiants arrived at RAF Hawkinge from West Malling on the 19th of July. The aircraft were turret-armed fighters that carried no forward-firing guns; their design relied on a rear-facing gunner in a powered turret. The crews had barely practised in the air while their aircraft were fitted with constant-speed propellers over the early summer, and the gunners were uneasy about escaping their turrets in an emergency.

    At 12:45 that morning, Theo Osterkamp led III./JG 51 on a patrol over the Dover area and spotted the Defiant formation. Recognising the aircraft, the German pilots attacked from the rear and below to avoid the turret's field of fire. Four Defiants were shot down on the first pass and a fifth as it sought cloud cover. Only the intervention of 111 Squadron, which shot down a Bf 109, allowed the four surviving Defiants to escape, one crash-landing, one written off, and two badly damaged.

    Osterkamp later noted that his pilots' delight at the result was tempered by their own awareness of mortality. Post-battle analysis found that the RAF controller had only scrambled the squadron after ground observers at Hawkinge had actually seen the German fighters, by which time the Bf 109s held the height advantage. Dowding told Churchill directly that many men had died. Churchill acknowledged Dowding's doubts about the Defiant and turned away.

    The 19th of July was the worst single defeat suffered by Fighter Command during the entire battle, with the RAF losing ten aircraft against four from the Luftwaffe. The German pilots quickly learned to identify the Defiant by silhouette and did not consider it a serious threat. The surviving aircraft saw very little action for the rest of the campaign.

  • At Bletchley Park, codebreakers working on Luftwaffe Enigma traffic had predicted the coming offensive. Decrypts from late June allowed the Air Ministry's Air Intelligence branch to forecast the opening of German operations, and by the 6th of July British analysts had reduced their estimate of German bomber strength from 2,500 to 1,250, though the true figure was somewhere between 1,500 and 1,700.

    The code-name Adlertag and references to the period from the 9th to the 13th of August were uncovered, though their purpose was not yet understood. As the Kanalkampf continued, Enigma gave more warning of targets, timing, and raid size, but this was sometimes too late to be useful and Luftwaffe changes at short notice could negate the intelligence entirely.

    A separate system, the RAF Y-stations, intercepted Luftwaffe voice transmissions between aircraft and ground control. German-speaking Women's Auxiliary Air Force and Women's Royal Naval Service personnel at listening stations around Britain, headquartered at RAF Kingsdown in Kent, forwarded these intercepts to local RAF headquarters and to Fighter Command's own centre. Voice intercepts could reveal formations assembling beyond radar range, the altitude and type of aircraft, orders to fighter escorts, meeting points, and planned return routes. It was not until mid-August, however, that this added significantly to radar reports.

    Coastal radar looked out to sea and lost track of raiders once they crossed the coast. The sheer proximity of Luftwaffe airfields to the Channel meant German aircraft could attack and withdraw before interception was possible. On the 10th of July, decrypts had shown that most Luftwaffe bomber units would be ready by the 8th of July, and photographic reconnaissance had confirmed runways being extended on the French side of the Channel.

  • By early August, the Channel was German by day. That was the judgement of historian Stephen Bungay, writing in 2000. But the same writer noted that controlling the Channel surface did not threaten Fighter Command in itself. The Luftwaffe still had to penetrate well beyond the coast to win an aerial campaign, and Hugo Sperrle, commanding Luftflotte 3, was already alarmed at German losses before the Channel phase ended. Albert Kesselring at Luftflotte 2 could ill afford to continue losing aircraft at the rate suffered in July.

    Historian Williamson Murray, writing in 1983, judged the Channel battles inconclusive. Peter Smith, writing in 2007, suggested they could be described as a German victory of sorts. The Luftwaffe had sunk British and neutral ships, forced the Royal Navy to suspend large convoys and close the Channel to ocean-going vessels for several weeks, and drawn Fighter Command into costly fighting over the sea. The RAF lacked an air-sea rescue service of the kind the Luftwaffe maintained with its Seenotflugkommando float-plane units, so British pilots who bailed out over water faced the same peril as their German counterparts.

    On the 1st of August, Hitler signed Directive 17, extending Luftwaffe operations to the British mainland and RAF targets. On the 13th of August, Adlertag, Eagle Day, the main assault on the RAF began. Convoy attacks continued for several more days, and the Kanalkampf's own accounting remained unsettled: Fighter Command had been drawn out as planned, but it had not been destroyed. The question of whether the Luftwaffe had gained enough to justify what it had spent would only be answered over the weeks that followed.

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Military operations of World War II involving Germany

Common questions

What was the Kanalkampf and when did it take place?

The Kanalkampf was the German term for Luftwaffe air operations against the Royal Air Force over the English Channel in July 1940, marking the opening phase of the Battle of Britain during the Second World War. Systematic German attacks against British coastal targets and convoys began on the 4th of July; on the 1st of August Hitler issued Directive 17 extending operations to the British mainland, and the main air offensive began on the 13th of August.

Why did Germany attack Channel convoys during the Kanalkampf?

Germany attacked Channel convoys to close the Channel as a supply route, draw RAF Fighter Command into battle over the sea where British pilots lacked an air-sea rescue service, and wear down Fighter Command before the planned invasion of Britain under Operation Sea Lion. OKL also chose coastal targets because they were easier to locate than inland objectives.

What happened to HMS Foylebank during the Kanalkampf?

HMS Foylebank, an anti-aircraft ship armed with four twin four-inch high-angle guns, was attacked by Ju 87 Stukas at Portland harbour on the 4th of July 1940. The gunners could not man their weapons in time; 104 bombs were dropped, many hitting the vessel, and 176 sailors were killed or died of wounds. The attack was recorded as the worst loss of life inflicted on British military personnel based in Britain up to that point.

What role did Enigma decrypts play in the Kanalkampf?

Enigma decrypts from late June 1940 allowed the Air Ministry's Air Intelligence branch to predict the start of the German offensive and reduce the British estimate of German bomber strength from 2,500 to 1,250 by the 6th of July. The code-name Adlertag and references to the period of the 9th to the 13th of August were uncovered, though their purpose was not understood until later. As the Kanalkampf continued, Enigma gave more notice of targets and raid sizes, but last-minute Luftwaffe changes could still negate the intelligence.

What was the disaster that befell 141 Squadron Defiants on the 19th of July 1940?

On the 19th of July 1940, twelve Boulton Paul Defiants of 141 Squadron were intercepted over Dover by Bf 109s of III./JG 51 led by Theo Osterkamp. The German pilots attacked from the rear and below to avoid the turret's field of fire, shooting down four Defiants on the first pass and a fifth as it sought cloud cover. Ten crew members were killed and one wounded, making it the worst single defeat of Fighter Command during the battle, with the RAF losing ten aircraft against four from the Luftwaffe.

Did the Kanalkampf succeed for Germany?

Historians disagree. Williamson Murray, writing in 1983, judged the Channel battles inconclusive. Peter Smith, writing in 2007, suggested they could be described as a German victory of sorts. The Luftwaffe forced the Royal Navy to close the Channel to ocean-going vessels for several weeks and drew Fighter Command into costly engagements, but it had not destroyed Fighter Command by the time the main assault began on the 13th of August.

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