armament was no better than many smaller classes. The later Type 1936 did, however, adopt heavy 150 mm guns. German destroyers also used innovative high-pressure steam machinery: while this should have helped their efficiency, it more often resulted in mechanical problems.

Once German and Japanese armament became clear, the British and American navies consciously focused on smaller, more numerous units. The British built a series of destroyers the A Class to I Class which were about 1400 tons standard displacement, had four guns and eight torpedo tubes; the American Benson class of 1938 similar in size, but carried five guns and ten torpedo tubes. The British realising the need for heavier gun armament built the Tribal class of 1936 (sometimes called "Afridi" after one of two lead ships). Theseships displaced 1850 tons and were armed with eight guns in four twin turrets and four torpedo tubes. These were followed by the J Class and L class destroyers with six guns in twin turrets and 8 torpedo tubes

Anti-submarine sensors included sonar (or ASDIC), although training in their use was indifferent. Anti-sub weapons changed little, and ahead-throwing weapons, a need recognized in WWI, had made no progress.

Operations in the inter-war period

During the 1920s and 1930s destroyers were often deployed to areas of diplomatic tension or humanitarian disaster. British and American destroyers were common on the Chinese coast, even supplying landing parties to protect colonial interests.

World War II

By World War II the threat had evolved once again. Submarines were more effective, and aircraft had become important weapons of naval