Build of the DEFIANT has been completed at the Nichols Brothers Boat Builders shipyard in Freeland, Washington. The No Manning Required Ship (NOMARS) program was launched by DARPA’s Tactical Technology Office in 2020 with the specific aim of building and then demonstrating at sea a Medium Unmanned Surface Vessel (MUSV), scalable to Large, able to spend long time at sea and perform long missions with exceptional reliability, a significant payload including weapons, and with the ability to refuel at sea. A 90% reliability at sea target has been set over the period of a year of operations.

Serco was selected for the DARPA NOMARS Phase 2 in September 2022, beating a rival bid by the team Leidos - Gibbs and Cox. Serco is the prime and design integrator, leading an industry alliance including Nichols Brothers Boat Builders, Submergence Group, Metron, Beier Integrated Systems, Thrustmaster of Texas, Leonardo DRS, Integer Technologies, and Caterpillar Marine. 

The 2022 contract covered an 8-month detail design period leading to construction of the DEFIANT vessel and includes a 3-month at sea technology demonstration period. This trial is expected to begin soon.

The team has some degree of connection with the UK through Submergence Group, a sister company to the british M Subs Ltd in Plymouth. Together, these two companies have worked on a pioneering USV control and autonomy system demonstrated ultimately on the MAYFLOWER Autonomous Ship that has crossed the Atlantic following the route of the famous ship of Pilgrims’ fame.

In order to de-risk the ability of refuelling at sea, underway, the US Navy and DARPA conducted a key test at sea last September using SERCO’s refuelling system installed on the experimental “uncrewed” (in reality, they have tiny safety crews) vessels MARINER and RANGER.

In that test, USV RANGER was fitted with a receiving station representative of the system designed for the DEFIANT, and the USV MARINER carried a refueling “mini-station” also custom-designed by NOMARS prime contractor Serco Inc. The whole evolution was conducted at sea without human intervention, although water, not fuel, was pumped across.

The DEFIANT is a 180 feet, 240 tons vessel (circa 55 meters long) which, for the moment being, can still only be partially observed as its superstructures are concealed under thick white tarpaulin.

SERCO has in the past provided clear indications of how it proposed to arm such a small hull, using the BAE Systems Adaptable Deck Lancher, a non-hull penetrating launcher that uses normal MK41 canisters slotted not vertically into the hull, but diagonally on a structure atop the deck. The Adaptable Deck Launcher has been initially developed to replace the octuple ESSM above-deck launchers on Aircraft Carriers and Amphibious vessels (the first ships will be fitted in the coming years) but is now also expected to become the first solution to produce heavily armed uncrewed surface vessels.

Graphics shown by SERCO in the pass, suggest that DEFIANT could be fitted with a pair of 2-cell ADL modules, one facing the bow and one the stern. SERCO has also repeatedly showcased the model of a slightly larger prospective “DAUNTLESS” vessels doubling that to 4 ADL modules.

With more beam available, the 4 cell of the Adaptable Deck Launcher could be installed instead.

The use of a small shipyard usually well disconnected from the production of complex warships is, in itself, a demonstration of the fact that many of these relatively inexpensive augmentation-vessels could be built quickly across multiple yards.

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