power, and another two fast-starting "boost" turbines for speeds of up to 29 knots (54 km/h) (such an arrangement is known as COGOG). Previously the Soviet Navy had used all-gas turbine propulsion on their Kashin class destroyers of the 1960s but the Iroquois were the first to be built to this scheme either on Canada or in the US. The design of the Iroquois was a major inspiration for the US's later Spruance class ships. They were originally fitted out for anti-submarine warfare, but the entire class underwent major retrofits as a part of the Tribal Class Update and Modernization Program, or TRUMP, in the 1990s. These refits had the effect of re-purposing the ships for air-defence, and the ships are now referred to as area air-defence destroyers.

Theof which was launched in March 2006.

The Chinese People's Liberation Army Navy has recently commissioned a number of new modern destroyers in addition to the four Sovremenny-class. Three new classes were launched since 2003, known as the Luyang, Luyang II and Luzhou class. The latter two are armed with long range air defense missiles, the indigenous HQ-9 and the Russian S-300 respectively. It has been speculated that once the PLAN has been satisfied with one of the two designs (either the 052C or 051C), it would be selected for series production as the next generation of advanced air defense destroyers for China.

In the US Navy, destroyers operate in support of carrier battle groups, surface action groups, amphibious groups and replenishment groups. The destroyers currently in use by the