Where are flags flown from a ship?

Answer 1

It depends on the type of ship, the type of flag in question, and whether or not the vessel is in port or underway at sea.

(This applies to U.S. Ships) Typically in port, a U.S. warship flies 2 primary flags, one on the bow mast and one on the stern mast. The one on the bow is known as the Jack, while the flag on the stern is known as the Ensign, and is the warship's national flag. The Jack on a U.S. warship is comprised of the blue field of stars typically seen on the U.S. National Flag, or Ensign; the British Jack, called the Union Jack, is a cross with an X over it and is widely known. By contrast, where U.S. warships fly the U.S. flag, the British Royal Navy has its own Naval Ensign, different from the National Ensign of England.

There are usually different sizes for holidays, in port and underway. Depending on the size of ship and occasion, some flags can be huge in size.

Surface warships will fly their Ensigns from the stern mast underway; Submarines are different in that they fly the Ensign from a stern mast in port, but from the bridge at the top of the fairwater (also known as the sail, the wide tower that rises from the deck about 30' above it).

Warships also fly what are know as Unit and Battle Flags, which denote commendations from the Division or Squadron Commander, President, etc. for battles or unit excellence in other areas. These are only flown in port at the quarterdeck.

Merchant vessels typically will fly the flag of the nation they're flagged under. Nations can have agreements with nations that have stronger navies to provide protection for their ships moving through hostile waters, and as such agree to fly the flag of the protecting nation. This is how the U.S. originally got involved militarily in the Persian Gulf, by reflagging Kuwaiti tankers. They will fly either their own national ensign from the stern mast, or the flag of the protecting nation. The bow mast usually has the flag of the company the ship belongs to.

Answer 2

Generally speaking, a pennant.

Strictly speaking, a "flag" flown on a ship is an "ensign", a pennant is a tapering flag only flown at the masthead of a vessel in commission.

Answer 3

Primary colors of naval vessels, be it U.S. or otherwise, are known as National Ensigns, or simply an Ensign.