The DD-21 class of ships is to be named after the late USN Admiral Elmo Zumwalt Jr., who was chief of naval operations from 1970 to 1974.

The DD-21 land attack destroyer is one of the latest examples of American military R&D. This new class of warship will use a system known as electric drive. This term refers to a transmission system, not an engine. This new system uses a single-source generator to supply all of the ship's power. This design is completely integrated with the ship's systems and eliminates the drive shaft and reduction gears found in traditional warships. This frees up large amounts of internal space for other uses. Design teams claim that they will use this room to give crew larger quarters and recreational facilities. Automation of ship systems is promised to reduce crew requirements to 95, or fewer. The DD-21 is intended to be a multi-purpose destroyer, designed specifically for land-attack warfare. Its primary mission will be to support American ground forces as a sort of sea-borne artillery. To do this job, the ship will be armed with two 155mm guns capable of firing 12 rounds per minute, with a range of 100 miles. These guns will be auto-loading and will be capable of firing conventional ammunition, or guided, rocket assisted shells. The craft will also be equipped with a long range missilesystem.

This project's future is currently in doubt due to political disagreements and limited naval funding.