As the United States Navy scrambles to bolster its dwindling attack submarine fleet, the service will have to rely more on unmanned underwater vehicles. Boeing and Huntington Ingalls Industries are working on one such option for the Navy. The two companies are teaming up to design and produce an Unmanned Undersea Vehicle (UUVs) for the Navy’s Extra Large UUV program.

“This partnership provides the Navy a cost-effective, low-risk path to meet the emergent needs that prompted the Navy’s Advanced Undersea Prototyping program,” Darryl Davis, president, Boeing Phantom Works, said in a statement.

“We are combining Boeing’s preeminent UUV maritime engineering team with our nation’s leading shipbuilder and Navy technical services company to get operational vehicles to the Navy years ahead of the standard acquisition process.”

Boeing Phantom Works advanced research division is already testing a new large UUV called the Echo Voyager in Southern California coast. The new robotic submarine is designed for multiple missions and could—if the Navy’s requirements called for—include a 34-foot long modular payload bay.

The fully autonomous Echo Voyager would offer better endurance and increased payload capacity over traditional UUVs. Indeed, the UUV is designed to operate at sea for months without a support vessel.

But while Boeing has a working prototype, the company is not a shipbuilder. That’s where Huntington Ingalls comes in. The shipbuilder would use its experience to help refine the UUV’s design and help build the new robotic submarine.

“We look forward to a long relationship with Boeing as we embark together to field this unmanned force-multiplier for the Navy,” Andy Green, executive vice president of Huntington Ingalls Industries and president of the company’s Technical Solutions division, said in a statement.

“I am confident this team will continue redefining the autonomy paradigm for UUVs.”

Testifying before the Senate Armed Services Committee on June 15, chief of naval operations Adm. John Richardson told the Congress that the service would have to rely more on unmanned systems in the future to make up for a shrinking fleet that will take decades to rebuild.

The Navy’s attack submarine fleet is set to dwindle down to 41 boats in 2029. That’s far below the previously set requirements for 48 attack submarines and more than a third less than 66 boats that new Navy has concluded it need after a recent review. Thus, highly capable UUVs will have to make up some of the difference in the meantime.

Dave Majumdar is the defense editor for The National Interest. You can follow him on Twitter: @Davemajumdar.