John Arbuthnot Fisher
John Arbuthnot Fisher (1841-1920), known as Jacky Fisher or 1st Baron Fisher of Kilverstone was a colorful and controversial British admiral of the fleet, considered to be the builder of the modern Royal Navy. He was First Sea Lord, or senior professional officer of the Royal Navy twice, in 1904-1910 and 1914-1915.
Innovations in ships
He regarded technology as a major benefit for the Royal Navy. One of his first causes was the revolutionary "all-big-gun" battleship, which quickly made obsolete every other battleship afloat or building, HMS Dreadnought (1905).
In the traditional warship design balance among speed, armament, and protection, he tended to emphasize speed. This had several consequences. One was the conversion of new ships from coal to oil fuel, which did have enormous advantages but made coal-rich Britain dependent on Middle East oil.
He also emphasized the battlecruiser, a vessel believed to be fast enough to run away from what its guns could not kill, and kill anything that could outrun it. This concept worked for commerce raiding, but was disastrous at the Battle of Jutland, where the less-protected battlecruisers fought battleships.
First World War
He returned, as First Sea Lord, to replace Prince Louis of Battenberg, in November 1914. In cooperation with Winston Churchill, then First Lord of the Admiralty, the civilian minister for the Navy, started an extremely large program to add 600 medium and light vessels to the Royal Navy. "Everything had to be subordinated to haste, and in fact most of the craft were actually delivered within six months. Although primarily designed for a great strategic move into the Baltic, which Lord Fisher had himself drawn up in detail, this vast armada was gradually diverted from its original purpose to various other uses - among them the naval attempt to force the passage of the Dardanelles; and it was the War Council's decision to proceed with this that ultimately (May 1915) led to Lord Fisher's resignation of his post as First Sea Lord."