United States Merchant Marine[1][2] are United States civilian mariners and U.S. civilian and federally owned merchant vessels. Both the civilian mariners and the merchant vessels are managed by a combination of the government and private sectors, and engage in commerce or transportation of goods and services in and out of the navigable waters of the United States.[3] The Merchant Marine primarily transports cargo and passengers during peacetime; in times of war, the Merchant Marine can be an auxiliary to the United States Navy, and can be called upon to deliver military personnel and materiel for the military.[4] Merchant Marine officers may also be commissioned as military officers by the Department of Defense.