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World War I · Navies
Ships and the War at Sea
Before the war, Britain and Germany raced to build huge all-big-gun battleships called dreadnoughts. Yet the great fleets met in full battle only once, at Jutland. The real war at sea was fought by submarines, mines and convoys, and it was a German U-boat campaign that finally brought the United States into the war.
The sinking of the Lusitania, May 7, 1915, as drawn for the Illustrated London News
Quick facts
The war at sea at a glance
| Main fleets | British Grand Fleet (Scapa Flow) vs. German High Seas Fleet (Wilhelmshaven) | |
| Strategy | Britain blockaded Germany; Germany used U-boats to try to starve Britain | |
| Big battle | Jutland, May 31 – June 1, 1916: about 250 ships, the largest naval battle of the war | |
| U-boats | Sank about 5,000 Allied and neutral merchant ships; Germany lost 178 U-boats | |
| Convoys | Merchant ships sailing in escorted groups from 1917 cut losses dramatically | |
| U.S. Navy | Escorted convoys, laid the North Sea Mine Barrage and carried troops; a U.S. battleship squadron joined the Grand Fleet | |
| The end | The High Seas Fleet surrendered in November 1918 and scuttled itself at Scapa Flow on June 21, 1919 |
The big picture in 30 seconds
Why the war at sea mattered
- The British blockade slowly starved Germany of food and raw materials.
- Unrestricted U-boat warfare brought America into the war in 1917.
- Convoys defeated the U-boats, a lesson relearned in World War II.
- Aircraft carriers and naval aviation first appeared in this war.
250
ships fought at Jutland
~5,000
merchant ships sunk by U-boats
2 million
U.S. troops carried to France
8,645
sailors killed at Jutland
The naval race
Dreadnought: the ship that changed everything
In 1906 Britain launched HMS Dreadnought. She carried ten 12-inch guns, twice the big guns of earlier battleships, and steam turbines made her faster than any of them. At a stroke every other battleship in the world was out of date, and the race began again from zero. Germany, under Admiral Alfred von Tirpitz and the Kaiser, built a High Seas Fleet to challenge the Royal Navy. Britain answered with ever more and ever bigger ships. The rivalry poisoned relations between the two countries.
Britain also built battlecruisers: ships with battleship guns and great speed, but thinner armor. At Jutland that weakness proved deadly.
The ships
Ships that fought the Great War
From giant battleships to small submarines and the liners and freighters they hunted.
May 31 – June 1, 1916
The Battle of Jutland
In May 1916 Admiral Reinhard Scheer took the German High Seas Fleet to sea, hoping to trap part of the British fleet. But British codebreakers in Room 40 had warned the Admiralty, and the whole Grand Fleet was already at sea. Off the coast of Denmark’s Jutland peninsula, Admiral Sir David Beatty’s battlecruisers met Admiral Franz Hipper’s. Two British battlecruisers, Indefatigable and Queen Mary, blew up within half an hour, and later Invincible too.
Then Admiral Sir John Jellicoe’s battleships arrived and twice “crossed the T” of the German line. Scheer turned away under cover of smoke and torpedo attacks and slipped home in the night. Germany sank more ships and claimed victory. But its fleet never again seriously challenged British control of the North Sea, and the blockade went on.
The U-boat war
Submarines, the Lusitania and the convoys
Germany declared the waters around Britain a war zone in February 1915 and began sinking merchant ships without warning. The sinking of the Lusitania on May 7, 1915, killed 1,198 people, including 128 Americans, and caused fury in the United States. Germany promised to restrain its U-boats, then on February 1, 1917, gambled on unrestricted submarine warfare, betting it could starve Britain before America could make a difference. That decision, with the Zimmermann Telegram, brought the U.S. into the war.
In April 1917 U-boats sank more than 860,000 tons of shipping, and Britain had only weeks of grain left. The answer was the convoy: merchant ships sailing together under the guard of destroyers, with U.S. Navy destroyers based at Queenstown, Ireland, helping from May 1917. Losses fell sharply, and the U-boats never came close to winning again.
America at sea
The U.S. Navy in the Great War
When the United States entered the war, its first contribution in Europe was naval. Admiral William S. Sims went to London and pressed for convoys. U.S. destroyers joined the hunt for U-boats, and a squadron of American battleships, including the New York and Texas, served with the British Grand Fleet as its Sixth Battle Squadron. In 1918 American minelayers helped lay the huge North Sea Mine Barrage between Scotland and Norway, about 70,000 mines in all.
Most important, the Navy’s Cruiser and Transport Force, along with British ships, carried about two million American soldiers to France. Thanks to the convoys, almost no troops were lost to U-boats on the way over.
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“There seems to be something wrong with our bloody ships today.”
Vice Admiral Sir David Beatty
At the Battle of Jutland, May 31, 1916, after two of his battlecruisers blew up
Year by year
The war at sea: a timeline
On land and in the air
Weapons of World War I
Machine guns, artillery, gas, tanks and fighter planes: the weapons that made the war on land so deadly.
Go deeper
Books and sources
- Dreadnought, by Robert K. Massie (1991)
- Castles of Steel, by Robert K. Massie (2003)
- Dead Wake: The Last Crossing of the Lusitania, by Erik Larson (2015)
- The Victory at Sea, by William S. Sims (1920)
- More recommended books