Had there been more submersible torpedo-boats (U-boats, as German submarines are known), Germany might well have survived or even won the war by isolating the British Isles. As we shall see, Hitler’s Germany might also have triumphed at sea a generation later. Fortunately, those leaders – civilian and military – who rule us pay little attention to history. The U-boat’s defeat in the Great War would be brought about mainly by Britain’s long-overdue decision, in 1917, to use heavily-armed destroyers to convoy merchant ships sailing for British ports with aircraft and airships lending an increasingly valuable hand.
Convoys forced U-boats to risk contact with these escorts, on the surface and in the air, in their hunt for merchant ships. By November 1918, more than 100 airships and thirty-seven out of forty-three maritime squadrons in home waters were engaged in anti-submarine duties. Although aircraft found it difficult to destroy U-boats, ‘they exercised, when employed as close and distant escorts to convoys, a most decisive effect: they rendered convoys virtually immune from successful attack.’
One bonus for the British was the surprising success of the De Havilland 6. More than 2,000 examples of this training machine had been hastily produced for the RFC, which found in 1918 that it had no use for them. It was saved by an Admiralty request for aircraft patrols off the coasts of northeastern England and Scotland. Although slow and lightly-armed, U-boat captains did not know this and prudently took evasive action whenever a DH 6 was sighted. This frail machine thus became one of the most ‘cost effective’ weapons in Britain’s air armoury. By the middle of 1918, Churchill announced, with his usual exaggeration, that the U-boat has been ‘definitely defeated’.
Although the Royal Navy had begun to build its own submersibles years before the war began, the Germans overtook the British in quantity and quality production. ‘We can wound England most seriously by injuring her trade’, wrote Admiral Friedrich von Ingenohl, commander of Germany’s High Seas Fleet. ‘The gravity of the situation demands that we should free ourselves from all scruples which certainly no longer have justification.’ As Arthur Hezlet (a submariner) wrote in 1960, submersibles were ‘an independent weapon’ that achieved great success, given its defensive weakness and small numbers.
On 4 February 1915 Germany declared that the waters around Great Britain and Ireland would be regarded, from the 18th, as ‘a war zone’. Any vessel found therein was liable to be sunk; her crew and any passengers would have to take to the lifeboats, if they could, and hope to be rescued. In response to President Woodrow Wilson’s protests unrestricted attacks were abandoned, but by the end of 1915 U-boats had sunk more than 1,000,000 tons of shipping, and would achieve even greater success in 1916. As more U-boats became available, it seemed to German naval and military chiefs that a war-winning weapon was to hand and they advocated a resumption of ‘unrestricted warfare’ in 1917.
They calculated that even if the United States declared war – which she did on 6 April – victory could be achieved before American soldiers were mobilised, trained, equipped and shipped across the Atlantic on voyages which might see many of them drowned as a result of U-boat attacks. The U-boat, wrote Walter Page (US Ambassador in Britain) in 1917 ‘is the most formidable thing that the war has produced, by far, and it gives the German the only chance he has to win’.
Aircraft would become of increasing value in the fight against U-boats. An improved version of the Short Type 184 seaplane, the Curtiss H12 Large America flying boat (developed from an earlier type by Commander John Porte, ‘a designer and innovator of genius’) and the excellent Felixstowe F2a all proved their worth. In April 1917, a ‘Spider Web’ patrol system, based on the North Hinder Light Vessel and linked to Felixstowe and Great Yarmouth was set up in the North Sea. It formed an octagon sixty miles in diameter and permitted the systematic search of some 4,000 square miles of sea, right across the preferred path of U-boats looking for targets. Although flying boats rarely sank or even damaged U-boats, they did force them to submerge, where they had to travel slowly and risked exhausting their electric batteries.
Flying boats were greatly helped by non-rigid airships, especially those of the NS (North Sea) class. Airships were able to hover, allowing extended observation, and carried a far heavier load of fuel and weapons plus the large wireless sets needed to send and receive messages clearly and promptly. By the end of 1917, it had been learned that aircraft attacking submarines needed to be able to drop a bomb containing at least 300-lbs of explosive, fitted with both an impact and a delayed-action fuse, to have any hope of causing serious damage. Their chief value, however, was as a deterrent: obliging U-boats to submerge and lose contact with their prey.
No aircraft had sunk a U-boat when 1917 began and during the first four months of that year U-boats sank more than 900 ships. Many were ocean-going vessels on which Britain’s supplies depended and the number of neutral nations sending ships to her ports fell to a quarter of the total in 1916. At the end of March 1917 Maurice Hankey feared that ‘we may yet be beaten at sea’ and news from the Western Front was just as bad. The battle of Arras in April turned into the costliest of British offensives and a French offensive in the same month ended in a disaster from which the French army scarcely recovered during the remainder of the war. In the air, the RFC lost more than 300 pilots: many of them young men with fewer than twenty hours’ solo flying trying to cope with better-equipped and far more experienced enemies. The American declaration of war in April could bring no comfort for months to come.
‘The great approach route to the south-west of Ireland,’ wrote Churchill in April 1917, ‘was becoming a veritable cemetery of British shipping, in which large vessels were sunk regularly day by day about 200 miles from land...’ The U-boat was rapidly undermining not only the life of the British islands, but the foundations of the Allies’ strength; and the danger of their collapse in 1918 began to loom black and imminent.
Most British or French citizens were unaware of this extreme danger because their governments did not release information about shipping losses and journalists were strictly censored. The impact of German air raids on England, beginning in May, could not be hidden from the general public, although officials did their best.
Since the war began, the navy had escorted every vessel carrying troops to and from the Western Front ‘without ever losing a man, horse or gun at sea’. Escort had traditionally been a prime task, but the Compulsory Convoy Act was repealed in 1872. Thereafter, naval officers persuaded themselves that it was enough to patrol routes, rather than to escort ships; to act offensively and not defensively. As Donald Macintyre wrote, this was like having ‘a single rifleman trying to protect a caravan in the Sahara by strolling at random to and fro along the route’.
David Beatty (commanding the Grand Fleet) sent the first of a stream of letters from January 1917 onwards to the Admiralty pressing for a greatly-improved and expanded RNAS to focus on support for the fleet and anti-submarine work. The secretary of the new Air Board (headed by Lord Cowdray) arranged the transfer from the Ministry of Munitions of responsibility for the supply and design of aeroplanes and seaplanes; a responsibility which the Admiralty had ‘clung to with the utmost tenacity’ in 1916.
Churchill – still out of office – addressed his fellow MPs in April 1917 on what he called ‘the whole story of the muddle in the air services since the beginning of the war’. He was especially severe in his criticism of the House of Commons for having allowed control to pass out of its hands. The pilots, he believed, had excellent qualities, but they suffered heavy casualties both in training and combat as a result of inadequate machines and poor organisation. He recalled that as long ago as March 1916 MPs had criticised that muddle. A committee was formed, as usual in Britain, drawn from members on both sides of the House and an Air Board was created under Lord Curzon, but it had no real powers and therefore achieved nothing. Churchill blamed Curzon ‘for taking the responsibility without proper power and authority’ and the House ‘for relaxing its vigilance, for being so easily put off’.
Curzon’s successor, Cowdray, resigned in June and Flight thought Churchill should be appointed Air Minister: a ‘man of imagination’, ready to act. He had always taken a deep interest in aviation, especially at sea, overcoming powerful opposition from ‘Old Navy’ officers. In addition, ‘even his worst enemies never denied him the possession of outstanding ability as statesman and administrator’. Arnold Bennett, an immensely popular novelist and playwright, also backed Churchill: ‘If Germany had imagination,’ he wrote, ‘she would concentrate in the air for the remainder of the war. She may yet do so.’
Beatty was supported by two men who made a vital contribution to victory in the war at sea: Norman Leslie (a civil servant in the new Ministry of Shipping) and Reginald Henderson (a junior officer, later an admiral). They discovered that the number of ocean-going vessels arriving and departing – the only ones that mattered – was, at most, about twenty a day. The Admiralty had been working on a figure of 5,000 because unthinking officials were counting every movement of every ship above 300 tons along every coast and concluded, reasonably enough, that such an enormous number could not be escorted. In fact, hundreds of vessels were already carrying essential coal to France, in what the Admiralty was pleased to call ‘controlled sailings’ without suffering any significant loss.
Reflecting on these dismal events after the war, Churchill got to the root of the matter: ‘There was in fact very nearly as good a chance of a convoy of forty ships in close order slipping unperceived between the patrolling U-boats as there was for a single ship’, given the vast extent of the sea. Moreover, wireless messages could deflect convoys from areas known to be dangerous. Better still, the escorting destroyers – being closely gathered – would have better prospects of sinking or at least driving away U-boats.
A Convoy Committee was set up on 17 May 1917, which began to organise a worldwide system of protection, but on 20 June the First Sea Lord, John Jellicoe, told the newly-created War Policy Committee (not including Churchill) that ‘owing to the great shortage of shipping due to German submarines, it would be impossible for Great Britain to continue the war in 1918’. The ‘bombshell’, as Douglas Haig noted in his diary, alarmed everyone present. Jellicoe was by then exhausted and despondent, yet he retained his high office for a further five months. Meanwhile, more anti-submarine vessels, including eighteen American destroyers, were being employed and the RNAS was expanding and taking on more efficient aircraft.
Even so, it was not until April 1918 that losses of merchant ships fell below 300,000 tons per month and in that month the construction of ships exceeded losses for the first time since unrestricted attacks began. Worse still, from a German point of view, U-boats proved unable to prevent an ever-increasing flow of American soldiers across the Atlantic and into France. Improving surface defences were greatly helped throughout 1918 with aircraft directed by naval commanders. Yet the Admiralty’s deep-seated faith in submarine-hunting operations (a dogmatism seen at its most obdurate in the Mediterranean) was still as alive and vigorous in 1918 as in previous years. Admiral Sir William Jameson, writing in 1965, concluded that the U-boat was ‘foiled rather than defeated’, but only by a narrow margin: between February 1917 and November 1918, it sank well over 3,000 British and Allied ships and killed nearly 15,000 merchant seamen.
The war at, under and over the sea had grown massively by the time of the Armistice. On the Allied side, over 300 destroyers, more than 4,000 auxiliary vessels and thirty-five submarines, assisted by no fewer than 500 flying boats, seaplanes and land planes, together with 100 airships, were at work. Opposing them were about 120 operational U-boats. This was in addition to the immense effort needed to produce and lay a vast number of mines and nets. The number of men required to man this gigantic force was approximately 14,000, with probably another 500,000 to build, refit and support them generally.
During 1918, aviation had become a weapon to be taken seriously, rather than the annoyance it had been at the beginning. David Beatty and other air-minded naval officers had hoped to create a force of torpedo-carrying seaplanes and ships capable of taking them to within hitting range of the German fleet in its harbours, but the necessary ships, aircraft and weapons were still under development at the time of the Armistice. Even so, naval aviation had become a valuable weapon for spotting U-boats, attacking enemy coasts and shipping as well as protecting those of Britain and her allies.
The U-boat had severely shaken the British government and the first article of the Armistice terms required the Germans to surrender them all. In 1921, when representatives of the five largest naval powers met in Washington, Britain strongly advocated the abolition of all submarines. She argued that this weapon was only effective as a commerce raider and asserted that it was of no value as a military weapon, which was obviously untrue, as would be revealed – even more plainly – after the outbreak of another war in 1939.