The navy is the seaborne part of the armed services. It is an essential part of keeping a country safe from overseas attack. This may require the navy to go to other parts of the world if that is thought the best way of defending a country. In recent years this has been using a core of aircraft carriers because that gives the effect of a floating airfield, allowing aircraft to reach inland targets. Much less emphasis is placed on guns on ships than used to be the case. Most effective arms are now guided missiles.
The idea of a navy goes back to ancient times.The Ancient Egyptians, Ancient Greeks and Ancient Romans all had navies. They use their navies to attack and conquer as well as to defend. The Norman Conquest was not a navy, it was an invasion force designed to do a single job. A navy is a more of less permanent fleet of vessels.
By the time of the Tudors in England, Spain and France already had built up navies. To counter the possible threat from them, Henry VIII formed the first English navy. This was probably built just in time, for within a few years of Henry's death, the English fleet was faced with defending against the Spanish invasion fleet called the Armada.
When two fleets meet, it is both the size and speed of a ship and the expertise of the captain that is important. No one is good without the other. That is why navies use the best ships they can get and train sailors to the highest levels.
During the time of Queen Elizabeth, the Spanish navy was used to try to protect its treasure ships crossing the Atlantic from the Spanish Main (the Caribbean shores). It failed to do this because its ships were large, slow and not very manoeuvrable compared to the English privateers.
But navies can only do so much. In the American Revolutionary War, the (by the British) navy was used to attack coastal ports, but it was working thousands of miles from its supply ports and that meant it could not offer support. (The same was true of the British army).
This is an important point. navies are not just about fighting. they are also about supplies. It is much harder to resupply from a long distance.
This was not a problem in 1805 when Britain won its most famous sea battle, because that was off the coast of Spain. It was the battle of Trafalgar, and it was led by Admiral Lord Nelson. He was a much more able sailor than the Spanish admiral and so was able to outwit the Spanish.
During the 19thcentiry, the British used the navy as a quick way of getting forces to any trouble spots in the empire.
The problem of using navies changed by the time of the First World war. In this case the British navy (at that time still the largest in the world) was used to stop the German navy getting its ships out of the North Sea. It did this by lining the British ships up across the North Sea from a base in northern Scotland. Although there was only one major battle (the battle of Jutland) in World war I, the navy succeeded in achieving the goal set for it.
By the time of the Second World War, submarines were bigger players in the navy of each country. The main problem the British had was to bring supplies across the Atlantic by convoys of ships. The cargo ships were slow and the navy escorts had to keep steaming around them, trying to detect the submarines. But it did not work very well. Only when they were helped by long-range aircraft was it possible to find the submarines and destroy them.
By the Second World war many countries had huge battleships designed to slog it out in a more of less face to face battle. But this was an outdated idea. Japan and America had aircraft carriers, but it was still early days in the aircraft carrier history. However, the Japanese showed how the war at sea had changed by launching an attack on Pearl Harbor in 1941 from their aircraft carriers. From then on, navies would not built new battleships, but instead concentrate on aircraft carriers (and today fast small ships with missiles).
But even by 1982, when the Argentineans waged unprovoked war on the British Falkland Islands, the way in which ships could steam thousands of miles and use their aircraft to defend themselves was shown brilliantly. The aircraft were Harrier Jump Jets.
Today the U.S. Navy in particular has enormous aircraft carriers (the Nimitz is the biggest), equipped to stay at sea for very long periods of time at great distances from the home ports. This is because strategy nowadays is to try to stop possible attack at source, not allow it to get closer to home. The wars in Iraq, for example, show this well.
