U.S. Navy Logistics Specialist 1st Class Ryan Enguacho, assigned to the Damage Control Division in the supply department aboard the aircraft carrier USS Carl Vinson, takes a level of knowledge test on maintenance and material management in Classroom No. 2 aboard a non-self-propelled barracks ship at Naval Air Station North Island, Calif., Sept. 18, 2012. The barracks ship serves as the messing and berthing barge for Sailors assigned to Vinson while she undergoes a docked planned incremental availability period, maintenance designed to extend a ship's service life by modernizing its shipboard systems.