10 Facts About World War One at Sea

Alex Browne

3 mins

02 Aug 2018

Here are 10 facts that tell the story of World War One at sea. Although primarily a land-war, there were significant skirmishes at sea.

World War One was primarily a land war, stretching from Jerusalem (pictured) to Africa. From the documentary Promises and Betrayals: Britain and the Struggle for the Holy Land on HistoryHit.TV.Watch Now

The safety of Britain in particular lay on its ability to control the seas, and the German U-boat campaigns against imports from the USA and elsewhere brought Britain to the brink of running out of supplies. Rationing was introduced as a direct result of the disruption and the Defence of the Realm Act (DORA) was subsequently introduced to prevent any future food crisis.

It also contributed heavily to the USA’s decision to intervene in the war. The sinking of US ships, together with the Zimmerman telegram (by which Germany conspired with Mexico to carve up a conquered USA) were threats the USA could not ignore.

1. The Battle of Heligoland Bight (August 1914) was the first naval battle of WW1

Top up your knowledge of the key events of World War One with this audio guide series on HistoryHit.TV. Listen Now

The British fleet ambushed and sunk three German light cruisers and one destroyer.

2. In 1914 SM U-9 (a German U-boat) sank 3 British armed cruisers in under an hour


3.  On 7 May 1915 the cruise ship Lusitania was torpedoed by a German U-boat


1,198 people were killed, including 128 Americans. The wrecklessness of German submarine warfare was an influence on the United States decision to join the Allies in 1917.

4. Between October 1916 and January 1917 1,400,000 tons of Allied shipping was lost to German U-boats


5. Germany built 360 U-boats, 176 of which were lost


6. 50% of all British merchant shipping was sunk by German U-boats


7. The Battle of Jutland (31 May – 1 June 1916) was the largest sea battle of the war

Dan Snow joins a team of marine archaeologists to explore two wrecks in the muddy murks of Portsmouth Harbour, believed to be German veterans of the Battle of Jutland. But will he make it across the treacherous mud to reach them? Find out by watching Dan Overboard: The Lost Wrecks of Jutland on History Hit TV. Watch Now

In the largest full-frontal naval battle of the war 14 British ships were lost to Germany’s 11. Britain also lost more than twice as many sailors than Germany. However, it was not the knock-out blow that the Germans required.

8. The North Sea was heavily mined by both sides


Under a 1907 treaty opponents could only mine 3 miles off an enemy’s coastline but both sides ignored this rule.

9. The success of German U-boat attacks caused the disastrous Passchendaele offensive


A main reason why the Passchendale campaign was launched was to capture the German U-boats based at Flanders. The attack failed however, with Britain suffering massive casualties.

10. The Allied naval blockade of Germany (August 1914 – January 1919) was devastatingly effective


Germany was heavily reliant on imports. An academic study in 1928 put the death toll caused by the blockade at 424,000 lives.