180315-N-JE719-186 GROTON, Conn. (Mar. 15, 2018) The virginia-class fast-attack submarine Pre-Commissioning Unit (PCU) Colorado (SSN 788) sits pierside prior to commissioning March 17, 2018. Colorado is the the U.S. Navy's 15th Virginia-class attack submarine and the second ship named for the State of Colorado. (U.S. Navy photo by Mass Communication Specialist 1st Class Jeffrey M. Richardson/Released)