Marines 3D Print a 7-Meter Raiding Craft, Then Take It to Sea in Okinawa

From Digital File to Ocean in Under a Month

A U.S. Marine Corps unit in Okinawa has turned the idea of expeditionary manufacturing into a working demonstration. During Exercise Valiant Shield 26, Marines from Intermediate Repair Company, 3rd Maintenance Battalion, built a 7-meter foam-hull raiding craft using a large-format polymer 3D printer, a CNC router, and a spray foam system, then put it in the water at White Beach Naval Facility.

The project was part of the Resilient Advanced Manufacturing For Contested Environments initiative, known as RAMFORCE. The goal was not to build a better boat for its own sake, but to prove that Marine units can manufacture critical equipment in theater instead of waiting for shipments to cross the Pacific.

How They Built It

The hull started as a digital file. Engineers from Naval Surface Warfare Center Carderock worked with the Marines to design a modular foam hull that could be produced with equipment small enough to deploy on short notice. The build used three primary tools: a CNC router for structural components, a large-format polymer 3D printer for the hull form, and a spray foam and coating system to finish the shell.

Materials were chosen specifically for worldwide availability. The idea is that any Marine unit could source the same inputs locally if needed, rather than relying on a contracted supply chain that breaks down under contested logistics.

A previous 5-meter prototype took roughly sixteen working hours and about eleven thousand dollars in materials. The team believes a scaled production line with twelve people could turn out a 5-meter platform every four hours and a 7-meter platform every six hours. That is still far slower than mass production, but it is fast enough to replace a damaged craft during a deployment without waiting for a replacement to ship.

Tested Manned and Unmanned

After fabrication, the hull received a protective polyurea coating and was fitted with a 300-horsepower Mercury outboard engine plus an autonomous control system from Fort Robotics. On June 29, the completed vessel entered the water and completed both manned and unmanned runs, including autonomous waypoint navigation.

Remote-control distances were limited by Japanese regulations, but the team noted that future versions could use satellite communications for greater range. The demonstration also included a separate experiment called Print on the Move, in which a commercially available polymer 3D printer kept fabricating a component while being transported on tactical vehicles and even while aboard the craft as it operated on the water.

What Comes Next

The equipment and partnerships from RAMFORCE stayed with the unit after the exercise. Marines from Intermediate Repair Company will continue refining the process. Senior leaders from III Marine Expeditionary Force and 3rd Marine Logistics Group observed the demonstration, which suggests the concept has traction beyond a one-time test.

The Marine Corps has been steadily expanding its use of additive manufacturing. Units across the Fleet Marine Force have already used 3D printing to produce custom tools, brackets, drone components, and replacement parts that would otherwise sit in supply chains for weeks. The raiding craft demonstration takes that logic to a much larger scale: instead of printing small replacements, the Corps is printing complete operational platforms in the field.

If the production timeline can hold at six hours for a 7-meter craft, the practical impact is clear. A unit that loses a landing craft to damage or enemy action could replace it within a day rather than waiting for a logistics chain that might not exist in a high-end fight. That is exactly the problem the Marine Corps is trying to solve right now.