The Admiralty introduces convoys

On 6 September 1939, three days after Britain declared war on Germany, the first convoys of the war – merchant ships under the escort of warships – sailed from the Thames estuary and the Firth of Forth. The next day the first ocean convoys left Southend and Liverpool. On the same 6 September the Northern Patrol, a squadron of old cruisers, began operations; its task was to stop ships bound for Germany in the waters between Scotland, the Faroe Islands and Iceland. Within a few days Britain had brought into play both of the instruments that had decided the outcome of the war at sea in the First World War: convoys, which protected its own shipping, and a blockade, which cut the enemy’s economy off from the world.

Some chronologies combine these events into a single day: on 6 September the Admiralty is said to have ordered the introduction of the convoy system and the Royal Navy to have begun the blockade. In fact the decisions had been taken earlier, and 6 September is the date on which they came into effect. The same chronologies also state that on 5 September the British freighter Bosnia became the first merchant ship sunk in the Battle of the Atlantic, and that this happened “off the coast of Portugal”. Both statements need to be qualified, as explained below.

The sinking of the Bosnia

On the morning of 5 September 1939 the German submarine U-47, commanded by Günther Prien, stopped the British steamer Bosnia in the Atlantic. She was a small ship of 2,407 GRT belonging to the Cunard White Star Line, sailing from Licata in Sicily to Manchester with a cargo of some 3,200 tons of sulphur. The encounter took place about 120 nautical miles north-west of Cape Ortegal – off the north-western coast of Spain, that is, not Portugal. Portugal enters the story because the survivors were brought to Lisbon.

Prien acted in accordance with the prize regulations, which since 3 September U-boat commanders had been under orders to observe. At around 8.15 a.m. the surfaced U-47 ordered the ship to stop. When the Bosnia began to transmit a distress call by radio, the submarine opened fire with its deck gun. One of the seamen was killed. The crew abandoned ship, and at 9.38 a.m. U-47 finished her off with a torpedo. The thirty-two survivors, including the master, Captain Walter Poole, were picked up by the Norwegian tanker Eidanger, which happened to be passing nearby and landed them in Lisbon the following day.

The Bosnia was not the first merchant ship sunk in the war. That was the passenger liner Athenia, torpedoed without warning on the evening of 3 September. She was, however, the first freighter sunk by a German submarine and the first ship sunk in accordance with the rules of prize law, having been stopped and her crew given time to take to the lifeboats. A few hours later, around midday on 5 September, U-48 stopped the freighter Royal Sceptre, carrying grain from Argentina, with gunfire north-west of Cape Finisterre. Her master was killed. On 6 September Prien sank the steamer Rio Claro, and on 7 September the Gartavon. In the same days U-38 sank the Manaar off the coast of Portugal; the ship had returned the submarine’s fire with her stern gun. For the Germans this was proof that British merchant ships were armed and did not deserve the protection of the prize regulations. The first week of the war cost Britain some 65,000 tons of shipping.

Convoys

In the First World War convoys had saved Britain. The Admiralty had long resisted them, believing that gathering ships into groups would only make the submarines’ task easier, and introduced them only in the spring of 1917, when losses had begun to threaten starvation. Losses then fell sharply. Between the wars some officers believed that ASDIC, the underwater sound-detection set, would make submarines less dangerous, but convoy plans were drawn up in case Germany again waged unrestricted submarine warfare. It was originally assumed that the Admiralty would introduce them only when the enemy began sinking ships without warning.

Preparations began before the outbreak of war. On 26 August 1939 the Admiralty took control of the movements of all British merchant ships. From then on they received their routes and instructions from the navy, and staffs of its naval control service were at work in ports throughout the empire. The First Lord of the Admiralty, Winston Churchill, who had returned to that office on 3 September, and the First Sea Lord, Admiral Dudley Pound, took the torpedoing of the Athenia as proof that Germany was waging unrestricted submarine warfare from the first day. The prepared system was therefore set in motion without waiting.

According to the British official history written by Stephen Roskill, the first merchant convoys in the strict sense – that is, sailing regularly from the same assembly port – left on 6 September on the east coast of England and Scotland, between the Thames estuary and the Firth of Forth: northbound as FN and southbound as FS, at first every other day in each direction. These waters, shallow and close to the German bases, were exposed to mines, submarines and aircraft, and they carried coal from Northumberland and Scotland to London and the southern ports. On 7 September the ocean convoys began: OA from Southend through the English Channel and OB from Liverpool through the Irish Sea. Ships bound south joined up off the Scilly Isles into OG convoys to Gibraltar. Two earlier groups of escorted ships, sent on 2 September from Gibraltar to Cape Town and on 5 September with a troop transport from the Clyde to Gibraltar, were not yet merchant convoys in the strict sense.

Over the following weeks they were joined by convoys bound for Britain: on 14 September from Freetown in Sierra Leone (SL), on 15 September a fast convoy from Kingston in Jamaica, on 16 September the first HX convoy from Halifax in Canada, and on 26 September the first convoy from Gibraltar (HG). Ships with speeds of 9 to 15 knots were assigned to convoys. Faster ships sailed independently, because their speed was considered protection enough, and so did slower ones, because they would have held up the whole group.

The system had serious weaknesses. There was a shortage of escort vessels, because destroyers were also needed by the fleet, for the transport of the British Expeditionary Force and for hunting submarines. Convoys leaving Britain were escorted only as far as about 12.5 degrees West, a few hundred miles from the coast. Beyond that the ships dispersed and sailed on alone, while the destroyers waited for an inbound convoy. Many ships that had been at sea when the war broke out sailed outside the system for weeks, and it was they that were the U-boats’ main prey. Even so, the effectiveness of convoys was quickly confirmed. By the end of 1939, 5,756 ships had sailed in convoy, of which submarines sank only four. Weekly shipping losses fell from 65,000 tons in the first week of the war to about 46,000 in the second and 21,000 in the third.

The Northern Patrol

The other half of the war at sea was the blockade of Germany. Once again geography favoured the British. Germany’s ports lay deep in the North Sea, and the British Isles barred their way to the ocean. The English Channel was narrow and easy to close, so ships sailing to and from Germany had to use the northern route, between Scotland and Norway or through the waters around the Faroes and Iceland. In 1914–1918 it had been guarded by the 10th Cruiser Squadron, known as the Northern Patrol.

On 6 September 1939 the Northern Patrol was re-established under the command of Vice Admiral Max Horton, a former British submarine ace of the First World War. It comprised the old light cruisers of the 7th and 12th Cruiser Squadrons, of the C and D classes, built during the previous war and designed for operations in the North Sea, as well as the newer HMS Emerald and HMS Effingham. Two cruisers were to patrol continuously between the Shetlands and the Faroe Islands, and three between the Faroes and Iceland. The area was soon extended to the Denmark Strait between Iceland and Greenland. The ships worked in extremely harsh conditions: storms broke aerials, smashed boats and damaged machinery, and their endurance was too short for long patrols in the North Atlantic.

By 28 September the ships of the Northern Patrol had stopped 108 merchant ships, 28 of which were sent for inspection to Kirkwall in the Orkneys. The patrol was not, however, watertight. During this period more than a dozen German freighters returning from overseas ports slipped through its lines, and the great liner Bremen, which had escaped from New York in the first days of the war, reached Murmansk on 6 September and later made her way back to Germany from there. The British fleet had taken its first prize even before the patrol was set up: on 3 September the destroyer HMS Somali stopped the German freighter Hannah Böge south of Iceland, the first ship of the war to be seized as a prize.

The Admiralty knew that the cruisers were only a stopgap. As early as the end of August it began requisitioning large passenger ships and converting them into armed merchant cruisers, armed with old 6-inch (152 mm) guns. The first of them entered service in September, and from October they were replacing the cruisers on the Northern Patrol’s lines.

Contraband control and the Ministry of Economic Warfare

Britain did not declare a formal blockade of the German ports in the sense of maritime law, which would have required the enemy coast to be effectively closed. Instead, as in the First World War, it operated a system of contraband control which in practice worked as a distant blockade. On 4 September the Admiralty announced that all merchant ships were liable to be stopped and searched, and published a list of contraband of war. Absolute contraband comprised arms, ammunition, explosives, fuels, means of transport and communication, and money and gold. Conditional contraband, which was seized if it was destined for the enemy, included food, fodder and clothing. France, which set up its own ministry of blockade, placed its ships taking part in these operations under British command.

Ships passing through the English Channel had to report for inspection at Weymouth or in the Downs off the Kent coast, and those bound for the ports of northern Europe and sailing round Scotland at Kirkwall. In the Mediterranean and on the way to it there were control points at Gibraltar, Haifa and Aden. Neutral ships, mainly Scandinavian and Dutch, sometimes waited there for several days, which provoked protests from shipowners and governments. According to official figures, in the first four weeks of the war the Royal Navy seized some 289,000 tons of contraband and the French navy about 100,000 tons.

The whole effort was the responsibility of the Ministry of Economic Warfare, created on 3 September together with Chamberlain’s War Cabinet. Its minister was the Conservative Ronald Cross, but the ministry was built up by the government’s chief economic adviser, Frederick Leith-Ross, who since 1937 had been urging politicians to prepare a blockade in case of war with Germany. He recruited bankers, economists, statisticians and lawyers. Their task was to gather information on cargoes and on the trade of the neutral countries, to pass it on to the contraband control service, and to compile the so-called blacklist of firms trading with Germany. Germany responded with its own contraband list, almost identical to the British one, and with controls on shipping in the Baltic and the North Sea.

Significance

The convoys and the blockade, set in motion in the first week of the war, determined the shape of the war at sea for the next six years. Convoys became the backbone of the Battle of the Atlantic. The German U-boats, which in the autumn of 1939 still hunted mainly lone ships, were in time forced to attack convoys, and from 1940 they did so in groups, at night and on the surface. The British responded by extending escorts across the whole ocean, and with aircraft, radar and codebreaking. The first months showed that they were short of escort vessels, and this shortage weighed on the Royal Navy until 1943.

The blockade worked less well than London had hoped. Germany, remembering the hunger of 1917–1918, had built up stocks and a rationing system, and after the signing of the Molotov–Ribbentrop Pact it could import raw materials and food from the Soviet Union and through Soviet territory. Swedish iron ore reached Germany along the Norwegian coast, beyond the reach of British patrols. The dispute over this route led in the spring of 1940 to the Norwegian campaign. After Germany had occupied most of Europe in 1940, the blockade covered almost the whole continent and became one element of a long war of attrition.

The Northern Patrol operated in this form until November 1940. Its armed merchant cruisers paid a high price: on 23 November 1939 HMS Rawalpindi was sunk by the German battleships Scharnhorst and Gneisenau between Iceland and the Faroes. Max Horton later commanded Britain’s submarines and, from November 1942, the whole of Western Approaches Command, as the Battle of the Atlantic entered its decisive phase. Günther Prien, who had sunk the Bosnia, won fame six weeks later with his attack on the fleet base at Scapa Flow.