A naval unit is a group of ships or submarines that are organized and trained for military operations. The three most common naval units are flotillas, squadrons, and armadas. A FLOTILLA is a small group of ships, usually consisting of four to eight vessels. A SQUADRON is a larger group of ships, typically consisting of 10 to 20 vessels. An ARMADA is the largest type of naval unit, usually consisting of more than 20 ships.