Besides the aircraft carrier and LPD/LHD there are 4 types of major surface ships. The Cruiser, Destroyer, Frigate, and Corvette. It seems as though the definition of each is becoming very murky. We have missile cruisers, anti-air frigates, air warfare destroyers, ect. Eventually ship classification may become simplified. Ships may be classified by tonnage and the number of verticle launch missiles are carried. Any type of ship that has the Aegis type system would be classified with the prefix "air defense" then either destroyer or frigate depending on tonnage and number of VLS. Under this classification(my idea), a destroyer would have over 80 VLS and weigh in at over 6,000 tons. A destroyer over 10,000 tons would be considered a large destroyer. A Corvette would simply be defined by tonnage. Anything under 4,000 tons would be a classified as a corvette. Then there is the Cruiser. The future of the cruiser is uncertain. The US is the only country with plans to build cruisers (CG(X)). If the Cruiser remains popular it would be the largest ship of the new classification. There is currently very little information on the CG(X). What is known is that it will have a similar hull to DD(X) but be larger and carry more missiles. Being that the DD(X) weighs in at 14,000 tons and has 80 VLS. Based on the new classification, the Crusier would be any ship that wieghs in above 15,000 tons.