A cruiser is a class of warship in a nation's navy. Above destroyer and below battleship, they can pack quite a punch, combining moderate speed, heavy armor, and bristling weapons all at once. A good example is the Northampton-class Heavy Cruiser. Used during WWII by the United States Navy and others, it has a powerful armament of nine 8 inch guns, heavy, thick armor, average speed, but unfortunately, no anti-sub capabilities. Almost all cruisers during WWI-II had no underwater depth charges, however nowadays with the advanced technologies of all countries, each cruiser can carry a formidable armament of charges.
There are different types of cruisers- Light, Heavy, Flak, and Battlecruisers, among others. Light cruisers are the fastest possible, with a modest armament. Although usually having rather weak armor, it makes up for it in speed and maneuverability. An example of this is the Cleveland-class Light Cruiser, also another cruiser during WWII. Carrying twelve 6 inch guns and twelve 5 inch guns, it has a rather heavy armament, but has incredible speed at nearly 33 knots. Heavy cruisers, like the Northampton-class, have rather weak anti-air armaments, but well more make up for it in armor and weapons. For example, the Takao-class Heavy Cruiser, in service under the Imperial Japanese Navy in WWII, packed a punch with a total of ten 8 inch main cannons along with four 5 inch secondary guns. The ship was formidable against British, American, Australian etc. captains of destroyers, fellow cruisers and the like, and were thereought feared, for good reason. Flak cruisers, like the Atlanta-class Cruiser, had a powerful armament of main cannons made for anti-air duty. Fighting with sixteen 5 inch guns, they were basically mobile weapons platforms, able to combat even the largest wing of fighter squadrons. Last but not least are Battlecruisers. Battlecruisers, like the British HMS Hood, are slightly different from a normal heavy cruiser, and are cousins to the more [in]famous Battleships. Battlecruisers, like their cousins, are some of the longest warships in a nation's navy, but instead of going all firepower and armor, Battlecruisers, like Light Cruisers, fabor maneuverability and speed over power and armor. This choice was one of the long-term causes of the sinking of the HMS Hood at the hands of the German Bismarck battleship.