Signal Flags

Signal flag A (Alpha) is a white-and-blue signal flag that means in maritime navigation: "I have a diver in the water; keep well clear and slow down."

In sailing, a protest flag is a solid red flag raised by a competitor to indicate that another boat has broken the rules of the race and that a protest is intended to be made of the incident.

Use of a protest flag according to the Racing Rules of Sailing:

• The Hail: You must immediately and loudly hail "Protest" at the first reasonable opportunity after the incident.
• The Use: You must conspicuously display a red flag attached to your rigging (typically on a shroud, backstay, or boom)
• Size Exception: Boats with a hull length of less than 6 meters are not required to display the flag, though they must still hail "Protest".
• Duration: The flag must stay flying continuously until you are no longer racing.

Note: The sailing instructions for the race and the applicable racing rules may affect the protest procedure.

The signal flag Q (Quebec) means that the ship is requesting customs clearance and entry inspection from the authorities.

Signal flag B (Bravo) is a red flag of the International Code of Signals (ICS). Meaning “Carrying, loading or unloading dangerous goods.”

Note!: Signal flag B is not the same as the single-color, rectangular red protest flag used in sailing competitions.

Signal flag L (Lima) means "stop the ship immediately" at sea, "the ship is in quarantine" in harbour. In sailing and dinghy racing it means "come within hail".