Marines 3D-Print a 7-Meter Raiding Craft in Okinawa

From Workshop to Water in Six Hours

Marines based in Okinawa just pulled off something that would have sounded like science fiction a decade ago. Over the course of Exercise Valiant Shield 26, a team from Intermediate Repair Company, 3rd Maintenance Battalion, 3rd Marine Logistics Group, built a working 7-meter foam raiding craft using a large-format polymer 3D printer, a CNC router, and a spray foam and coating system. On June 29, they put the hull in the water at White Beach Naval Facility and ran both manned and unmanned operations, including autonomous waypoint navigation.

The exercise ran from June 1 through July 1 under a program called RAMFORCE, short for Resilient Advanced Manufacturing For Contested Environments. The goal is not to refine a single boat design. It is to prove that Marines can manufacture expeditionary platforms where they are needed, when they are needed, without waiting weeks for parts to cross the Pacific.

A Scalable Recipe, Not a One-Off

Engineers from Naval Surface Warfare Center Carderock helped the team develop the modular foam hull under the Manufacturing Attritable Systems at Scale, or MASS, effort. The materials were chosen deliberately for worldwide availability, so a deployed unit could source them locally if necessary. A previous 5-meter prototype took about 16 working hours and roughly $11,000 in materials. With a 12-person crew, the team estimates it could produce a 5-meter platform every four hours and a 7-meter version every six.

After printing, the craft got a protective polyurea coating, a 300-horsepower Mercury outboard, and an autonomous control system from Fort Robotics. Remote-control range during the test was limited by Japanese regulations, but future versions could use satellite links for much greater reach.

Print on the Move

The boat was only the most visible part of RAMFORCE. In a related experiment called Print on the Move, Marines tested whether commercial polymer 3D printers could keep working while riding in tactical vehicles or aboard watercraft. One printer kept fabricating a part during the trip to White Beach and continued printing while the raiding craft was actually under way.

Other parts of the exercise focused on repairing what units already own. The nScrypt nRugged system diagnoses faults on circuit cards, repairs damaged electrical pathways, and replaces components in the field rather than swapping entire assemblies. A separate cold spray team blasted powdered aluminum and nickel onto worn metal surfaces, then machined the new layer back to specification. Oak Ridge National Laboratory demonstrated hybrid manufacturing that scans a damaged part, rebuilds it with wire-fed additive manufacturing, and finishes it with machining in one machine.

Why This Matters

For forces operating across the vast distances of the Indo-Pacific, supply chains are a vulnerability. A broken bracket or missing hull can mean the difference between a mission that happens and one that waits. RAMFORCE is part of a broader Marine Corps effort to put additive manufacturing tools in the hands of maintainers, from custom brackets and drone parts at the II MEF Innovation Campus to a 7-meter boat built in Okinawa.

The equipment and partnerships from the exercise stayed with Intermediate Repair Company after Valiant Shield ended. That matters because the goal is not a headline. It is a capability that keeps improving.