The US Navy 3D printed a 30ft long concept submersible craft in under a month

The US navy, in collaboration with the Office of Energy Efficiency & Renewable Energy and the Oak Ridge National Laboratory (ORNL), have 3D printed their first submersible craft.

The Optionally Manned Technology Demonstrator is the largest 3D printed vessel currently with the US Navy.

The team used a large, industrial-sized machine called Big Area Additive Manufacturing (BAAM) at the ORNL to build the craft. The submersible, as reported in a post published by the Department of Defense, is a clone of a Seal Delivery Vehicle, which is used by the Navy to covertly deliver up to six soldiers or sensors and equipment by towing them underwater behind a ship.

According to a report by the US Navy, soldiers inside the submersible have to be in full scuba gear and the craft is fully flooded when in use.

The advantage of 3D printing over traditional methods is that it not only reduces the time needed to build a vehicle this size, but also reduces the overall cost of such an operation.

Composite carbon fibre was used to print out six individual pieces, which were then attached together to form the hull of the vessel. The entire printing process took only two days to finish according to the DoD. The project, from planning to execution took four weeks.

A traditional hull for a craft this size, according to the Department of Energy, would take three to five months to manufacture.

The absolute cost advantage of printing such a craft is also substantial. The office of energy reports that cost of a traditional hull ranges from $600,000 to $800,000 (£457,000 to £609,000). The 3D printed version has cut that cost by 90%, says the report.

While the craft is only a prototype, the navy has said that fleet-ready models could be ready by 2019.

The model is not testable in the water or operational, but demonstrated, "the art of the possible", according to the Navy.

"The ultimate vision for this system is to create a disposable or limited-use vehicle that can be reconfigured very quickly and has modular energy and data systems," said Kevin Lin, a member of Carderock's Advanced Power and Energy Group.

Now that the proof of concept has been successful, the Navy has planned to go ahead with a second version of the 3D printed craft, which will be tested at the Carderock wave pool that can mimic harsh sea conditions, according to the office of energy.

DoD has been making use of 3D printing technology in a number of applications that include small parts to drones and even components that go into missiles.

Ramjets, for example, traditionally cost around $14,000 to manufacture, but they can be 3D printed at a cost of about $6,000, noted the DoD. The process involves using a laser beam to fuse powdered steel.

The quick turnaround time of a few hours, the low cost of production and the ability to solve supply and logistical issues makes 3D printing an essential part of Naval research. "Additive manufacturing is a potential game-changing technology for naval warfare" said John Burrow, deputy assistant secretary of the Navy for research, development, test and evaluation. "It accelerates capability development and will increase our readiness by reducing obsolescence or long lead time issues."