BAE Systems Inc. may not be building U.S. Navy submarines, but it still has an important role supplying parts to them.

The Arlington-based U.S. subsidiary of its British parent recently announced it scored a $72 million contract to produce and deliver the propulsor systems for a batch of Virginia-class submarines. This award applies to all of the so-called “Block IV” subs — 10 submarines being bought under a multiyear procurement between fiscal 2014 and fiscal 2018. This is the fourth batch being procured since fiscal 1998.

Work under this contract is scheduled to run between 2016 and 2022. If all options are exercised, it could be worth up to $162.9 million.

The propulsor shrouds the propeller. It’s used to both improve the efficiency of the propeller and help quiet it so as to lower its sonar signature. BAE has provided propulsors for more than 20 submarines, beginning with the three Seawolf-class ships that were procured between fiscal 1989 and 1991.

I spoke with BAE’s submarines program manager, Jason Warnke, and he told me that the opportunities go beyond simply providing the propulsors. BAE has a large manufacturing facility in Louisville, Kentucky, with welding machinery to build more parts for submarines. Warnke sees a chance to provide the launch missile tubes found in the Virginia-class submarines — especially as the U.S. Navy begins procuring the larger Virginia payload module subs which will up the launch missile tubes from two to four to fire more tomahawks.

BAE built the canisters that launch Trident II submarine-launched ballistic missiles from the current generation of Ohio-class submarines.

Beyond that, Warnke said BAE would also have an opportunity to do the same for the future replacement of the current fleet of Ohio-class ships, a nuclear submarine that the Navy plans to begin buying in fiscal 2021.

BAE’s submarine business is pretty limited in what it does. It makes specialized hardware that is built to requirements authored by the two main shipbuilders, Huntington Ingalls Industries Inc. (NYSE: HII) in Newport News, Virginia, and General Dynamics Corp., (NYSE: GD) which has shipyards in Groton, Connecticut, and Quonset Point, Rhode Island.

These two companies build the Virginia-class ships and are slated to split the work on the future Ohio-class subs.