A Marine drags securing chains to an Assault Amphibious Vehicle in the well deck of USS San Diego (LPD 22) during the 15th Marine Expeditionary Unit’s Certification Exercise, May 31, 2017. CERTEX is the final at-sea training period to certify the 15th MEU and America Amphibious Ready Group in preparation for their upcoming deployment. The Marines are with the 15th MEU Battalion Landing Team. (U.S. Marine Corps photo by Cpl. Timothy Valero)