180110-N-JE719-136 ATLANTIC OCEAN (Jan. 10, 2018) Machinist Mate (Auxiliary) 3rd Class Allen L. Meredith, left, and Machinist Mate (Auxiliary) 3rd Class Nicholas Abbott, right, perform normal diesel operation checks verifying pressure, temperature, and the operational status of the diesel engine aboard the Pre-Commissioning Unit (PCU) Colorado (SSN 788). Colorado is the 15th Virginia-class attack submarine and is scheduled to be commissioned March 17, 2018. (U.S. Navy photo by Mass Communication Specialist 1st Class Jeffrey M. Richardson/Released)