Destroyers, the most common large combat ships in modern navies, are larger than frigates. Both types of warship help protect troop-carrying vessels and aircraft carriers from submarines and planes. Some also are armed with guns for shore bombardment.

In the sea battles of the Falklands, the long reach of the destroyers and frigates has been provided by antiaircraft missiles.

The British destroyer Coventry, sunk by bombs Tuesday in a major Argentine air attack, displaced 4,500 tons when fully loaded and was 463 feet long. It had a speed of 29 knots and carried a crew of about 280.

The frigates Antelope and Ardent, also sunk by Argentine aircraft since Britain's landing on the Falklands Friday, displaced 3,250 tons and were 384 feet long. They had a speed of 30 knots and a crew of about 175.

Both destroyers and frigates are smaller than cruisers such as Argentina's General Belgrano, torpedoed and sunk by a British submarine May 2. A cruiser in turn is smaller than a battleship.

In the U.S. Navy, the use of the term frigate has changed in recent years. Formerly, a U.S. frigate was a ship larger than a destroyer. Today, however, the U.S. Navy's FFG7 is called a frigate even though it is smaller than modern destroyers.