DD - Destroyer
Destroyers are multiroles ships, used as escort for carriers or amphibious ships. Their role grew in importance from World War I onwards. Some nations such as USSR or France built specialized destroyers for anti-sub warfare or anti-air warfare, but modern trend is to build multirole platforms, like in the USA. Destroyers can be used alone, ahead of a task force, or closer to the main group, where it can work in cooperation with other units.