In a new report, the Government Accountability Office (GAO) calculates that the U.S. Navy has spent $1.5 billion over the past decade supporting submarines that it could not deploy. 

According to GAO, the Navy has been unable to begin or complete the vast majority of its attack submarine maintenance periods on time.  GAO report examples Los Angeles-class fast attack submarine the USS Boise (SSN 764) , that was scheduled to enter a shipyard for an extensive period of repairs, fixes and modifications in 2013. The shipyards, however, did not have the space, time and personnel to conduct the repairs in accordance with the original schedule. The submarine still hadn't gotten attention from shipyard workers by 2016, some three years later, at which point officials determined the USS Boise was unfit for operations, GAO reports.

Report says that the Navy has spent more than $1.5 billion into support attack submarines that provide no operational capability.