DIVER'S FLAGS
You will be shown 3 flags in class that are used by divers:
Every letter of the alphabet is represented by a colored flag. Almost all of them have a dual meaning. Each represents a letter, and most have a second meaning. These flags are recognized by captains of ships throughout the world.
The Alfa (sic) flag is white and blue with a triangular piece missing from the blue front. It represents the letter "A" as well as meaning: "Diver Down; Keep Clear." This flag must be flown from vessels that have diving operations going on in international waters, coastal waters, and other waters where commercial and international shipping is taking place.
The red flag with a diagonal white stripe from the upper mast to the lower outer corner was originally specifically for divers in the United States. The flag is not an official flag in that it is not part of the International Code of Signals Flags. Therefore a person acquiring a Captain's License does not have to memorize the meaning of the "Divers' Down Flag" but does have to know the Apfa flag means divers are in the water. It is the most common flag flown by divers in the USA. It is now used in many areas of the world and may be flown with the Alfa flag. It generally means there are divers within a specified number of feet from the flag. Exactly what legal requirements are connected with the use of the flag is determined by the law in each State. In New York State, Section 45, 1a of the State Navigation Law states that unless you are the vessel that is involved in diving operations, boats must stay at least 100' away from the flag.
There are many pleasure boaters that do not have a clue as to the meaning of any of the divers' flags. Just because the flag is flying does not completely protect the diver. It is important for divers to make sure local boating training courses, such as those conducted by the US Coast Guard Auxiliary, include information on "Diver Down" flags.
The US Coast Guard clarified their rules on diver flags in a release on March 9, 1984. The following are excerpts from that document:
CG 02-84: ...."The alpha [sic] flag is to be flown on small vessels engaged in diving operations whenever these vessels are restricted in their ability to maneuver if divers are attached to the vessel. But in sports diving, where divers are usually free swimming, the alpha flag does not have to be shown and the Coast Guard encourages the continued use of the traditional sports divers flag. The Coast Guard says the distinction it wants to make clear is this: The alpha flag is a navigational signal intended to protect the vessel from collision. The sport diver flag is an unofficial signal that, through custom, has come to be used to protect the diver in the water. It is the responsibility of the operator of the diving vessel to determine if his craft's movement are restricted. To be most effective, the sport diver flag should be exhibited on a float in the water to mark the approximate location of the diver...."
The Papa is a blue square with a white square in the middle. When the flag is displayed it means the vessel is about to sail. This flag has been used to bring divers back to the surface and discontinue diving operations. When the flag is up, the tenders realize the end of diving has been signaled and start the divers toward the surface. Sometimes large cruise ships will tell their departing tourists to return to the ship when the Papa flag is hoisted to the top of the vessel.
THE INTERNATIONAL CODE OF SIGNALS FLAGS