An ENSIGN is the lowest rank of a naval officer, typically a commissioned officer in the armed forces holding a rank just above a sub-lieutenant. A BOSUN is a senior non-commissioned officer in the navy, responsible for supervising the crew and maintaining discipline. An ADMIRAL is the highest rank of a naval officer, typically a commissioned officer in the armed forces holding a rank above a vice-ADMIRAL. A COMMODORE is a naval rank used in many navies that is superior to a captain, but below a rear ADMIRAL. An EXEC is a naval officer who is responsible for the day-to-day operations of a ship or submarine. A MATE is a naval officer who is responsible for navigation and the safety of the ship. A SEAMAN is the lowest rank of a naval officer, typically a non-commissioned officer in the armed forces holding a rank just above an ordinary SEAMAN.