20世纪初,海上战争只是对付海面威胁,数万吨的战列舰、数千吨的巡洋舰是水面战斗的主力,舰上主要装备的是大口径火炮和鱼雷。第一次世界大战中,飞机开始投入海上战斗,随着产生航空母舰,潜艇亦初露锋芒。第二次世界大战中,航空母舰成为水面战斗的主力,潜艇已对水面舰艇构成严重威胁,有攻无防的庞然大物战列舰走向衰落。巡洋 At the beginning of the 20th century, the maritime war was only a threat to the sea and a tens of thousands of tons of battleships. Thousands of tons of cruisers were the main force in surface combat. Major ships were equipped with large-caliber artillery and torpedoes. During the First World War, the aircraft started to fight at sea. As the aircraft carriers were produced, the submarines also showed signs of strength. During the Second World War, the aircraft carrier became the main force in surface combat. The submarine has posed a serious threat to the surface ships. The non-defensive monster battleship has been declining. Cruising