The High Seas Fleet (German: Hochseeflotte) was the main battle fleet of the Kaiserliche Marine (Imperial German Navy) during World War I. The fleet was based at Wilhelmshaven in the Jade estuary, and commanded by Admirals Friedrich von Ingenohl (1913–1915), Hugo von Pohl (1915–1916), Reinhard Scheer (1916–1918), and Franz von Hipper (1918). It posed such a threat to the Royal Navy's control of the seas around Britain that the British Grand Fleet had to remain concentrated in the North Sea for the duration of the war, even as many urgent tasks in other theatres of war went undone for lack of ships.
The High Seas Fleet was outnumbered three to two by the British Grand Fleet; however, during some periods in the first year of the war an equalization of forces in the North Sea was almost achieved not by Germany's will but by the British dispersal of ships to numerous other parts of the world. In the latter part of the war the ratio tipped in the British favour. The German navy was unwilling to risk a head-to-head engagement of fleets, preferring a strategy of raids into the North Sea with the aim of drawing out a section of the British fleet that could be cut off and destroyed. However, the battles at Heligoland Bight (28 August 1914), Dogger Bank (24 January 1915) and Jutland (31 May 1916) were inconclusive and did not change the strategic position.
As the British blockade caused increasing economic hardship in Germany, the German Imperial Navy concentrated its resources on unrestricted submarine warfare in an effort to win the First Battle of the Atlantic and strangle the British war effort. Aside from two sorties in August 1916 and April 1918, the High Seas Fleet languished in dock for the remainder of the war.
In October 1918, with the army facing defeat and the civil population starving, Scheer decided to launch a do-or-die attack on the Grand Fleet. Knowing that the attack would be vetoed, he neglected to inform the government of Prince Max von Baden. But when orders were given to sail from Wilhelmshaven on 29 October 1918, many sailors either refused to obey them or deserted. The plan was abandoned, but these events led to the Kiel Mutiny, to revolution in Germany, the fall of the Imperial government on 9 November and the Armistice on 11 November 1918.
Under the terms of the Armistice, the High Seas Fleet went into internment at the Royal Navy's base at Scapa Flow in Orkney. In "Operation ZZ" on 21 November 1918, sixty Allied battleships escorted eleven battleships, five battlecruisers, eight cruisers and forty-eight destroyers of the High Seas Fleet into captivity. On 21 June 1919, Rear Admiral Ludwig von Reuter gave the order to scuttle the ships to prevent their falling into British hands. Fifty-three ships sank. Nine German officers and sailors were killed as the British attempted to prevent the sinkings, and were the last casualties of the First World War.
Swedish historian Alf W Johansson considers the creation of a German High Sea Fleet a prime example of a strategic blunder. Translated from his book Europas krig ("Wars of Europe"):
Admiral von Tirpitz's High Seas Fleet had proven to be a gigantic miscalculation; a product of vanity, conceit, and fuzzy military thinking. It proved useless as a means of exerting political pressure; instead of forcing Britain closer to Germany it drove them closer to France. When the war came, it was unfit as a military instrument.
It can be added that the final attempt to use it as a military instrument resulted in the overthrow of the political system that built it.