A maritime flag is any of the various types of flags utilized on seafaring vessels. In most situations, maritime flags designate a ship's country of origin. Though they are employed on civilian vessels and other modes of water transport, these items are often engaged as naval flags, flown by the navy of a ship's home country. There are several types of maritime flags, including ensigns, rank flags, pennants, jacks, and signal flags, and a strict protocol traditionally governs their usage.
An ensign maritime flag is a ship flag that is flown when a vessel is either leaving or entering a harbor. They are also flown when a ship is sailing through foreign waters, and they may be required to be flown at the advance of a warship. The ensign flag plays an important role on any warship, traditionally flown between morning and sunset, when different flags are hoisted for display. A lowered ensign flag typically signifies that a warship has surrendered.
Rank flags are a style of maritime flag flown by the military to indicate the rank of a high-level officer on board; the ship is usually the flagship of that officer. In modern military seafaring, the flag tells other ships that they must follow the appropriate protocol to honor the high-ranking officer on board his ship. Navies around the world utilize rank flags, including the United States Navy, the Royal Navy, and the Hellenic Navy.
A pennant is another type of maritime flag used by the military. These flags are in the traditional pennant shape: a long triangle coming to a gradual point at one end. They can be emblazoned with any number of marks signifying the ship's purpose. Pennants are commonly utilized to specify a warship on maneuvers, give notice that a ship is involved in church services, and as an invitation for nearby ships to join the head officer for cocktails.
Jacks are among the most prevalent of all types of maritime flags. They bear the crest, symbol, or seal of the ship's country of origin. They are most readily flown on warships, though many other vessels may utilize jacks as well. The jack is flown when the ship is aground or at anchor.
There are a huge number of maritime flags known as signal flags. These flags communicate with other ships and can represent individual letters of the alphabet or general communications. Examples of signal flags include messages denoting that a diver is underwater, that dangerous goods are on board, or that the ship is disabled and in need of assistance.