The Royal Navy is part of the naval branch of the military forces of the United Kingdom, alongside the Royal Marines, RFA, RMR, and the RNR. With 91 commissioned vessels, it is considered the world's second most powerful navy in terms of global force projection, closely following the United States Navy. The Royal Navy was the most powerful armed force on the planet, from the 17th century, to the end of the 20th century, and was critical in propelling Great Britain as the predominant superpower for nearly 3 centuries. Up until the end of the Second World War, the Royal navy was the world's largest, until it was surpassed in size by the United States Navy, and the Soviet Navy.
The first navy of England was established in the 9th century by King Alfred the Great. During the medieval period England had a significant naval force, defeating the French navy at the Battle of Sluys in 1340, in the early years of the Hundred Years War. Later, under Queen Elizabeth I the English fleet defeated the Spanish Armada in 1588, but suffered several later defeats at the hands of the Spanish navy.
A permanent naval service, under Parliamentary control, was developed during the rule of Oliver Cromwell in the 1650s. In 1707, with the union of England and Scotland into the United Kingdom, the Royal Scots Navy was merged into the Royal Navy. The Royal Navy suffered defeats against the Spanish navy at Cartagena de Indias in 1741, during the War of Jenkin's Ear, and against the French navy at the 1781 Battle of the Chesapeake, which was atoned by victory in the Battle of the Saints the following year. The most important naval engagement of the 18th century was the Battle of Quiberon Bay in November 1759, which, like Trafalgar 46 years later, saved England from possible invasion.
During the Napoleonic Wars the Royal Navy played a major role, reaching the height of its achievements at the Battle of Trafalgar in 1805, where a British fleet commanded by Lord Nelson decisively defeated a combined French and Spanish fleet. During the remainder of the 19th century the Royal Navy became the world's dominant naval force and played a major part in building and defending the British Empire. In 1906 HMS Dreadnought became the Royal Navy's first "all-big-gun" battleship, a key turning point in British naval history; subsequently, large battleships became the dominant form of sea-power.
In both the First World War and Second World War, the Royal Navy played a key role in keeping the United Kingdom supplied with food, despite German attempts at a naval blockade using submarine warfare. After the Second World War, during the Cold War years, the disintegration of the British Empire forced Britain to downsize its navy, while the United States Navy took on the major role as the world's dominant sea power. The Royal Navy was re-organised with a strong emphasis on anti-submarine capabilities in the North Atlantic Ocean, to counter the potential threat of the Soviet Union.
In 1982, the Royal Navy was the principal British force in the Falklands War. The British submarine HMS Conqueror, a nuclear-powered submarine, sank the Argentine cruiser ARA General Belgrano during this conflict, the first time in naval history that a nuclear-powered submarine had engaged an enemy ship with torpedoes.
The Royal Navy operates a variety of highly sophisticated ships, including an aircraft carrier, HMS Illustrious, helicopter carrier HMS Bulwark, 2 landing platforms, 4 ballistic missile submarines, 6 fleet submarines, and 57 other ships. It also operates a variety of fixed wing aircraft, and non-fixed wing craft such as helicopters. The Royal Navy is considered by the United States, as a blue water navy.