The War at Sea

Laws introduced in Germany in 1899 encouraged a Naval Arms race between Britain and Germany, with the
German government hoping that a powerful German Fleet would prevent Britain from intervening in a war in
Europe. The Naval Arms Race was largely between two Dreadnought (a type of battleship) programmes.

Naval tactics

Germany began their U-boat campaign at the very start of the War with an aim to sink merchant ships bringing vital supplies to Britain who relied on imports from all over the world. 

In 1915, Germany turned to ‘unrestricted submarine warfare’ where merchant ships were sunk without warning, regardless of nationality. This tactic swayed public opinion in the USA, who had previously decided to remain neutral, to turn against Germany. By 1917, Germany had more submarines carrying more torpedoes and so to reduce losses of merchant ships the Royal Navy started using convoys. As the convoys approached Britain, they would be met by naval escort vessels and aircraft to protect them from attack.  

Blockades were a common tactic during the First World War. In the Mediterranean, the Royal Navy contributed to the blockade of both the Austro-Hungarian and Ottoman Empires. The longest of these blockades was the one on Germany.

Years Ahead

Guy N Pocock (1880-1955)
Days to come, days to come
But who shall ask of the wandering foam,
Te weaving weed, or the rocking swell,
Te place of our sailor-dead to tell ?
From Jutland reefs to Scapa Flow
Tracks of the wary warships go,
But the deep sea-wastes lie green and dumb
All the days to come.
Years ahead, years ahead,
Te sea shall honour our sailor-dead !
No mound of mouldering earth shall show
Te fghting place of the men below,
But a swirl of seas that gather and spill;
And the wind’s wild chanty whistling shrill
Shall cry “ Consider my sailor-dead! “
In the years ahead.


In February 1915 the Royal Navy tried to force the Ottomans (today’s Turkey) out of the War by taking ships through the narrow Dardanelles and attacking Constantinople. On 18th March 1915 three ships were sunk and three more were badly damaged by Turkish mines. When it was clear the Allies could not win, it was the Navy’s job to evacuate the Army, but its role in the Mediterranean did not end there. The Royal Navy supported Allied land operations in Egypt, Palestine and Macedonia, as well as keeping open the routes from Europe to Asia via the Suez Canal.

Merchant Navy 

Germany’s ‘unrestricted submarine warfare’ meant that it was very dangerous to serve in the Merchant Navy. Merchant sailors were recruited from inside and outside of Britain, including from Hong Kong, western African countries, Jamaica, Barbados and other British territories in the West Indies. 

Merchant sailors were armed in an attempt to deter U-boat attacks. About 14,000 merchantmen died during the First World War, 4,000 were killed during a three-month campaign in 1917. Some of the many who lost their lives are commemorated on the Tower Hill memorial in London.  



Naval Power during the First World War was often used to control trade routes. For example, the Siege of Tsingtao secured trade routes in the Pacific for the Allies.

The North Sea

© IWM Art REPRO 000323 the second division at jutland

In the winter of 1915-16, a massive naval battle in the North Sea was expected, but the German Navy was not strong enough to risk a meeting. Instead they opted for raid on the British coast. The German Navy hoped to gradually whittle down British superiority to the point where they could meet the British Royal Navy on equal terms. The British moved their Grand Fleet to relative security of Scapa Flow, in the Orkney Islands, and so the North Sea became a maritime no man’s land.

The Battle of Jutland to the British and Skaggerak to the Germans began on 31st May 1916 and was the only time a massed fleet of huge battleships fought head-to-head. The long awaited clash ended inconclusively as both sides claimed victory. The British lost more ships, but after the battle the German fleet rarely ventured out of its harbours. 

St. George’s Day Raid

On 23rd April 1918 (St. George’s Day) the British naval forces planned to block German Access to the North Sea at Zeebrugge and Ostend in Belgium by attacking the mole which provided shelter for U-boats in the harbour and protected access to their inland base. Meanwhile, three British ships were deliberately sunk in the harbour to block access. The raid did not succeed in blocking the submarine canal but was hailed as a daring and courageous attack, raising public morale in Britain. 

© IWM ART 1311. bridge of the hms cantebury. when the great naval raid took place on zeebrugge and ostend.

Minefield across Dover

In response to the German U-boat campaign, the Royal Navy set up the Dover Barrage. This operation started early in the war and involved laying a huge minefield between the coast of Belgium and Dover. The intention was to deter the U-boats from accessing this area. The Barrage was set up with nets, to trap the enemy’s ship, and a large minefield.

The minefield did not always prove successful. The mines were not always reliable and the netting was not always perfectly placed, sometimes leaving gaps for the German U-boats to duck under. 

© iwm art 1118.hms firedrake signalling mn - stop immediately - to german uboats.

© iwm art 1118.hms firedrake signalling mn - stop immediately - to german uboats.

Women’s Royal Naval Service (WRNS)

The Women’s Royal Naval Service (WRNS), sometimes known as Wrens, was formed in 1917. The Wrens were Cooks, Stewards, Despatch Riders, Sail Makers and worked in intelligence. Some women transferred from WRNS to WRAF when that was formed in 1918. By the end of the war in 1919 there were 7,000 Wrens and, although the unit proved successful to the war effort, it was disbanded when the war was over.


On the morning of 21st November 1918, HMS Cardiff met the German High Seas Fleet. Its ships were led towards the Grand Fleet and surrendered. The German ships anchored at Scapa Flow and waited while negotiations took place at Versailles. 

After the Armistice, all surviving German U-boats and ships were surrendered under the terms of the Treaty of Versailles. However, on 21st June 1919, German crews decided to start sinking their ships rather than allow the Allies to seize them. 

Naval Officer Speech Bubble: Our 63rd Royal Navy Division fought in a number of land battles during the war, including Gallipoli, The Somme, Gayrell and Passchendale, over 10, 000 men were killed fighting on the Western Front.