On This Day, Jan, 31, 1917 – Germany Announces Unrestricted Submarine Warfare

WWI sub

1917 – Germany announced its policy of unrestricted submarine warfare.

As early as 1915, Admiral von Pohl had wanted neutral shipping in the so-called ‘war zone’ (the English Channel and the rest of the water around the United Kingdom that then included the whole of the Irish coastline) attacked. He believed that the sinking of a few neutral merchant ships at the start of a campaign of unrestricted submarine warfare would be enough to scare off most ships from trading with Britain. However, on this occasion Pohl was not listened to for two reasons. The first was that the U-boat fleet was simply not big enough to execute a successful campaign against the numerous merchant ships that sailed around the British coast as in February 1915, there were only 21 U-boats available in total. At times only 4 U-boats patrolled the British coastline as some were in for repairs or an overhaul. Second, many still believed that such an approach was unethical and against the rules of war.

The Battle of Jutland, however, showed that the German Navy was not strong enough to defeat the Royal Navy. Therefore, any attempt by the German surface fleet to attack British merchant ships was not tenable as any fleet leaving bases like Kiel would have been met with a considerable fleet from the Royal Navy. Therefore, any attacks on Britain’s lifeline of shipping from America would have to be done by submarines. Rather than do this piecemeal, Bethmann Hollweg decided on a policy of wholesale unrestricted attack.

When the German Chancellor Bethmann Hollweg announced Germany’s intention to use unrestricted submarine warfare, his one major concern and fear was that it would provoke an American response – in this he was to be correct.

Why did Germany resort to such a tactic that was likely to provoke such a response from America? By 1917, the war was not going well for Germany on the Western Front. Unrestricted submarine warfare was a result of desperation and the belief that the ferocity of such a tactic might just keep America out of the war if the results were spectacular and shocking enough.

The impact of U-boats was overestimated in Germany. At the start of the war, the German submarine service had a couple of high profile successes against British naval targets but after this, successes became rare.


1606 – Guy Fawkes was executed after being convicted for his role in the “Gunpowder Plot” against the English Parliament and King James I.

1747 – The first clinic specializing in the treatment of venereal diseases was opened at London Dock Hospital.

1858The Great Eastern, the five-funnelled steamship designed by Brunel, was launched at Millwall.

1865 – In America, General Robert E. Lee was named general-in-chief of the Confederate armies.

1865 – The 13th Amendment to the U.S. Constitution was passed by the U.S. House of Representatives. It was ratified by the necessary number of states on December 6, 1865. The amendment abolished slavery in the United States.

1876 – All Native American Indians were ordered to move into reservations.

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1893 – The trademark “Coca-Cola” was first registered in the United States Patent Office.

1929 – The USSR exiled Leon Trotsky. He found asylum in Mexico.

1930U.S. Navy Lt. Ralph S. Barnaby became the first glider pilot to have his craft released from a dirigible, a large blimp, at Lakehurst, NJ.

1936 – The radio show “The Green Hornet” debuted.

1940 – The first Social Security check was issued by the U.S. Government.

1945 – Private Eddie Slovik became the only U.S. soldier since the Civil War to be executed for desertion.

1950 – President Harry Truman announced that he had ordered development of the hydrogen bomb.

1958Explorer I was put into orbit around the earth. It was the first U.S. earth satellite.

1971 – Astronauts Alan B. Shepard Jr., Edgar D. Mitchell and Stuart A. Roosa blasted off aboard Apollo 14 on a mission to the moon.

1971 – Telephone service between East and West Berlin was re-established after 19 years.

1995U.S. President William Clinton invoked presidential emergency authority to provide a $20 billion loan to Mexico to stabilize its economy.

2000 – John Rocker (Atlanta Braves) was suspended from major league baseball for disparaging foreigners, homosexuals and minorities in an interview published by Sports Illustrated.

2001 – A Scottish court in the Netherlands convicted one Libyan and acquitted a second in the bombing of Pan Am Flight 103 over Lockerbie, Scotland, that occurred in 1988.


Source: Historylearningsite.co.uk; On-This-Day.com