The Zumwalt-class destroyer, the DDG-1000, began as the DD-21 program after Congress required the Navy to replace the shore bombardment capability lost when the Iowa-class battleships retired. The result displaces over 15,000 tons, about 40 percent more than a standard destroyer, yet looks like a fishing boat on radar thanks to a wave-piercing tumblehome hull that slopes inward, a shape often compared to the Civil War ironclad CSS Virginia. It runs with a crew of 147 through a Linux-based network on IBM blade servers, places 80 missile cells in a Peripheral Vertical Launch System around the hull, and generates 78 megawatts through a turboelectric drive fed by two Rolls-Royce gas turbines.

The plan for 32 ships fell to 24, then seven, then three: USS Zumwalt, USS Michael Monsoor and USS Lyndon B. Johnson. With $9.6 billion in research spread over three hulls, the program reached $22.5 billion, triggering a Nunn-McCurdy breach and a cost near $7.5 billion per ship. Its two 155mm Advanced Gun Systems were built to fire the Long Range Land Attack Projectile, but with so few ships each round rose to between $800,000 and $1 million, and the Navy canceled the ammunition. Budget cuts removed the SPY-4 radar and the ship lacked the Aegis software used for ballistic missile defense, so starting in 2023 the Navy began removing the guns to fit Conventional Prompt Strike hypersonic missiles.

• The Government Accountability Office found only four of the design’s 12 critical technologies were mature.
• Water sleeting over the hull and exhaust mixed with cool air aim to match the ship’s surface temperature to the sea.
• Explosions in the peripheral launch cells are designed to vent outward into the ocean rather than into the ship.
• The LRLAP had an 83 nautical mile range, and the water-cooled guns could fire 10 rounds a minute from a 750-round automated magazine.
• For comparison, a Virginia-class nuclear attack submarine costs about $2.7 billion.