The War at Sea: Jutland, U-boats and Convoys
A War on the Sea Lanes
In 1914 Britain was an island fed by ships. Around 60% of its food and almost all its raw materials came by sea. Germany had spent twenty years building a fleet to challenge British naval supremacy under Admiral Tirpitz’s programme. Yet for most of the war the German High Seas Fleet stayed in port. Britain’s strategy was to use its much larger Grand Fleet, based at Scapa Flow in Orkney, to impose a distant blockade. The blockade slowly cut Germany off from food and raw materials and would by 1918 contribute decisively to internal collapse.
The Battle of Jutland was fought on 31 May–1 June 1916 in the North Sea. Admiral Sir John Jellicoe commanded the British Grand Fleet; Admiral Reinhard Scheer commanded the German High Seas Fleet. Britain lost 14 ships and 6,094 men; Germany lost 11 ships and 2,551 men. After Jutland the German fleet rarely left port.
Jutland: The Only Big Fleet Action
Jutland was the only major fleet engagement of the war. Scheer hoped to lure part of the British fleet into a trap and destroy it before the larger Grand Fleet could intervene. He sent Vice-Admiral Hipper’s battlecruiser squadron south to draw out British battlecruisers under Vice-Admiral Beatty. Beatty took the bait and pursued; Scheer’s battleships then appeared. But Jellicoe with the main Grand Fleet was right behind Beatty — Scheer found the trap reversed against him.
The fighting was confused. Visibility was poor, signalling broke down, and Beatty’s battlecruisers proved tragically vulnerable: HMS Indefatigable, Queen Mary and Invincible all blew up when shells reached their magazines, killing more than 3,000 men. Beatty famously remarked, ‘There seems to be something wrong with our bloody ships today.’ Twice Scheer turned away under cover of destroyer smoke and torpedo runs to avoid the British battle line, and slipped home overnight. Jellicoe declined to pursue at night, knowing that a single torpedo hit on the British flagship could change the strategic balance of the war.
Germany claimed a tactical victory because it had sunk more British tonnage and lost fewer ships and men. Britain claimed strategic victory because the German High Seas Fleet returned to harbour and barely ventured out again. Winston Churchill later wrote that Jellicoe was ‘the only man on either side who could have lost the war in an afternoon’ — meaning the loss of the Grand Fleet would have ended British control of the sea, and with it Britain’s blockade and food supply. By that yardstick, Jutland was a clear British strategic victory: the blockade tightened and Germany would now turn to a different naval weapon.
U-boats and Britain’s Lifeline
Locked out of surface combat, Germany turned to the U-boat. Submarines could slip past the blockade and attack merchant shipping in the Atlantic. There was, however, a legal problem. Under the ‘cruiser rules’ of long-standing prize law, a warship stopping a merchant vessel had to give the crew time to abandon ship before sinking it. A submarine that surfaced to do this lost its only advantage: stealth.
Germany twice tried unrestricted submarine warfare. The first attempt began in February 1915 and produced the most famous incident: on 7 May 1915 the U-20 sank the Cunard liner RMS Lusitania off the southern coast of Ireland, killing 1,198 people, including 128 American citizens. American outrage forced Germany to back off in late 1915. The second attempt began on 1 February 1917 and was a deliberate gamble: Germany calculated that knocking Britain out of the war by starvation in six months was worth provoking the United States into joining the war late.
Germany resumed unrestricted submarine warfare on 1 February 1917. April 1917 was the worst month for British shipping — 881,000 tons of merchant shipping sunk. Britain was estimated to have around six weeks of food left. The convoy system, introduced from May 1917, transformed the war at sea.
The Convoy System
The Royal Navy was initially against convoying merchant ships. Senior admirals argued that warships were better used hunting U-boats than escorting traders, and that gathering merchantmen into groups would simply hand the U-boats bigger targets. Junior officers and David Lloyd George disagreed. The first experimental convoy from Gibraltar to Britain in May 1917 lost no ships. The system was rolled out across the Atlantic over the summer.
Convoying worked because it inverted the U-boat’s problem. The ocean is large; merchant ships scattered through it gave U-boats targets in many places. A convoy concentrated those targets into a small area surrounded by destroyers, depth charges and (later) air patrols. To attack a convoy, a U-boat had to find one in the first place — a much harder needle in a much bigger haystack — and then survive the escort. The combination of convoying with depth charges (a type of underwater bomb), hydrophone listening gear and aircraft cut shipping losses dramatically. By the end of 1917 monthly losses had fallen by more than half. Around 5,000 Allied merchant ships were sunk over the war, but by 1918 the U-boat threat was contained.
The British blockade tightened year by year. In the ‘Turnip Winter’ of 1916–17, German civilians were reduced to substituting turnips for almost every staple. By 1918 around 750,000 German civilians had died from blockade-related malnutrition and disease, according to a German government commission of inquiry after the war. The blockade did not directly stop the German army in 1918, but it broke the will of the home front: the naval mutiny that broke out at Kiel in November 1918 began among hungry sailors ordered to make a final sortie. The contribution of the blockade to German defeat is hard to overstate — and Jutland made it possible by keeping the High Seas Fleet bottled up.
Significance
The war at sea had three decisive effects. First, the British blockade slowly starved Germany of food, raw materials and morale. Second, the German U-boat campaign of 1917 came close to forcing Britain out of the war by starvation but instead drew the United States in — American protests against unrestricted submarine warfare combined with the Zimmermann Telegram to bring the USA into the war in April 1917. Third, the convoy system from May 1917 contained the U-boat threat and ensured the safe arrival of the American Expeditionary Force in 1918. The war was won partly on the sea lanes.