Sailors "at home" in crew quarters of ship bound for North Africa on the way to invade Sicily during World War II, July 1943. Triple deck bunks fold up during daytime to make room for mess tables and recreation. Soldiers live in narrow compartments on either side of the tank deck. The United States Navy (USN) is the naval warfare service branch of the United States Armed Forces and one of the seven uniformed services of the United States. A troopship is a ship used to carry soldiers, either in peacetime or wartime. Operationally, troopships are normal ships, and unlike landing ships, cannot land troops directly on shore, typically loading and unloading at a seaport or onto smaller vessels, either tenders or barges.