February 1, 1917 saw Germany restart its unrestricted submarine warfare which targeted all ships trading with Britain.
Historic England marked the centenary of the declaration by sharing never before seen images of German submarines, wrecked on the Cornish coast in Falmouth, UK.
The submarines had been surrendered by Germany after the war ended in 1918 and were on their way to be sunk as gunnery targets. But stripped of their engines, submarines were difficult to tow and occasionally sank or wrecked on Britain’s beaches, as in the case of the Falmouth U-boats.
According to Historic England, the photographs were taken in 1921 by the notable naval officer Jack Casement on what was probably his last official posting before he retired. They were donated to the Historic England Archive by Casement’s family.
Germany declared unrestricted submarine warfare for the second time on 1st February 1917 and began torpedoing ships without warning, meaning passengers and crew had no chance of escape.
Nicknamed Der magische Guertel, or the magic girdle, the aim was to strangle Britain to the brink of starvation and desperation by stopping both supplies getting in and exports getting out.
All ships trading with Britain were seen as targets by the Imperial German Navy, including those from neutral countries such as Norway, Denmark and the United States. The targeting of American ships ultimately brought the United States into the war in April 1917.
Even hospital ships were targeted by German forces during unrestricted submarine warfare, provoking worldwide outrage. Ships like the Rewa, torpedoed in 1918, were unarmed and painted with the internationally recognised symbol of the Red Cross but were still targeted.
Despite some interesting solutions to combat the U-boat attacks, from travelling in convoys to dazzle camouflage which broke up the outlines of ships, making their direction of travel more difficult to see, the losses were huge.
During 1916, 431 British ships were sunk by German U-boats worldwide but in 1917 following the declaration of unrestricted submarine warfare, the number lost nearly tripled to 1263.
A third of the Submarine Service’s total personnel lost their lives during the First World War – the highest proportion of any branch of the armed services.
Roger Bowdler, Director of Listing at Historic England said: “The declaration of unrestricted submarine warfare in February 1917 was a decisive moment in the First World War. Germany’s tactic led to devastating losses for many nations but it also horrified the world.
It was seen as uncivilised, ungentlemanly and ultimately brought the might of the United States into the war. By commemorating this day we can better understand its consequences and remember the many people who lost their lives in this way.”