Fully Autonomous Warship With No Crew Onboard Spotted In Washington

A mysterious naval vessel spotted in Washington state has been identified as the USX-1 Defiant, a fully autonomous warship developed under the U.S. Defense Advanced Research Projects Agency’s (DARPA) No Manning Required Ship (NOMARS) program.

The vessel was seen moving through Saratofa Passage in Puget Sound. It is designed to operate without a single human onboard for long durations at sea.

DARPA recently confirmed that construction of Defiant was completed in February 2025, and the vessel is now preparing for extensive in-water testing both dockside and at sea.

The agency has scheduled a multi-month demonstration in spring 2025, to evaluate its capabilities.

The Defiant is 180 feet long and weighs 240 metric tons. It falls under the U.S. Navy’s Medium Uncrewed Surface Vessel (MUSV) category.

The vessel is designed from the ground up without any provisions for a human crew. The warship doesn’t feature any living quarters, food storage and safety considerations for human needs, boasting advantages in cost, size, efficiency, and stealth capabilities.

DARPA has stated that the NOMARS program aims to challenge traditional naval shipbuilding by proving that a fully autonomous warship can function reliably and efficiently even in harsh ocean conditions.

The agency highlights benefits like greater hydrodynamic efficiency, improved survivability in high-sea states, and enhanced resistance to adversary interference.

Recent images of the vessel, though partially covered, reveal a slender hull design with a large central mast housing various radars and communication antennas. Another smaller mast at the bow supports additional sensors.

The vessel also features large open deck spaces designed to accommodate modular payloads, including shipping containers for mission systems or general cargo.

One of its most notable features is the potential for armed configurations. The contractor, Serco Inc., has demonstrated how Defiant can be equipped with the Adaptable Deck Launching System (ADL)- a modular launcher capable of firing anti-ship, surface-to-air, and land-attack missiles, as well as anti-submarine rockets.

The base model of Defiant costs approximately $25 million.

The NOMARS program emphasises “graceful degradation”, meaning the ship is designed to withstand failures of individual components while maintaining operational capability for at least a year at sea at speeds of 15 knots or more.

In December 2024, DARPA tested an at-sea refueling system that could support uncrewed vessels like Defiant. The test involved two other U.S. Navy USVs, Ranger and Mariner, showing how an unmanned ship can refuel at sea without human intervention.

Serco is already working on a larger, more advanced uncrewed vessel called Dauntless. This new ship could potentially be armed with up to four ADLs and carry various payloads.

References: TWZ, The Sun

Source: Maritime Shipping News