DARPA’s Underwater 3D Printing Push Targets Faster Port Repairs

DARPA is asking civilian industry and academia to help develop ways to 3D print concrete underwater using seawater plus seafloor sand and clay. The goal is to fix and build critical port infrastructure in shallow shoreline waters and in waters up to 100 meters deep.

The long-term aim is a fully autonomous, deepwater-capable system that could build or repair ports, seawalls, artificial reefs, underwater oil and gas pipe protection, and telecommunications cable protection.

Business Insider reports that DARPA sees current underwater construction methods as too slow, costly, logistically burdensome, and environmentally intrusive for expeditionary or military operations. Existing approaches can require specialized equipment and transported materials, which limits their usefulness for fast repairs in difficult maritime environments.

Autonomous underwater construction could be especially useful for units that need to repair damaged maritime facilities without relying on traditional heavy logistics.

The proposed system would use AI to determine what mix of sediment and water would work best in different locations. That focus on local materials is key: using ocean water and seafloor sediment could reduce dependence on transported construction supplies.

If the technology matures, it would expand the military’s broader interest in autonomous systems beyond drones, ground robots, and land-based 3D printed construction.

Ports, piers, seawalls, and related facilities face constant damage from saltwater, humidity, storms, and corrosion. These sites matter to the US military because they serve as logistics hubs and naval bases in both peace and war.

Business Insider notes that many maritime military facilities are already in poor condition, including Coast Guard facilities where around 45% of facilities such as piers and moorings were past their expected service life, according to a report released last year.

The underwater printing effort fits into a broader DARPA interest in concrete durability and rapid infrastructure repair. Another early-stage DARPA program is focused on predicting how concrete infrastructure, including aircraft runways, will age and fail before cracks appear.

In 2023, DARPA also gave $10 million to a University of Colorado effort for a nearly five-year project exploring self-repairing concrete inspired by human vascular systems and fungi.