INFO SHEETS > LEAD, SUPERVISE
Alfa flag (international)

Any reproduction prohibited on any medium whatsoever without the written consent of the publisher and the author.
The Alpha flag stands for “Immersed Divers”.
The red flag with a white diagonal or a Saint-André cross means “Isolated diver”.
Section A322-79 of the Sports Code, applicable in metropolitan France and in the overseas departments, merely mentions that diving is reported in accordance with “current regulations”. To know these regulations, you must have access to the decrees of the maritime prefectures (the behavior to be taken differs according to the maritime regions) and to the international regulations.
RIPAM (INTERNATIONAL REGULATIONS)
In general, maritime prefectures refer to rule n ° 27 of the International Regulations for Preventing Collisions at Sea (RIPAM).
Here is an excerpt:
A vessel participating in diving operations (…) must show:
(i) in the most visible place, three lights superimposed, visible over the entire horizon, the upper and lower lights being red and the middle light white; [night dives].
ii) a rigid reproduction, at least one meter high, Flag "A" of the International Code [Alpha Flag] of Signals. He must take measures so that this reproduction is visible all over the horizon.
Annex I point 6 c) of RIPAM states: “c) On board a vessel of less than 20 meters in length, the marks may have smaller dimensions, but in relation to the dimensions of the vessel and the distance between them may be reduced accordingly. "
No details are given as to “lower dimensions“.
For information :
- In French inland waters, according toarticle A4241-48-36 of the Transport Code (see below): “for vessels less than 7 m in length, the height of the rigid reproduction of flag A is at least 50 cm high“.
- In Florida the minimum size of the alpha flag is 50 cm x 60 cm (20 '' x 24 ''): Chapter 27 of the 2003 Florida Statutes.
- In Australia (New South Wales) the minimum height is 40 cm.
MARITIME PREFECTURE OF THE MEDITERRANEAN, ORDER N ° 019/2018
The modifications resulting from decree 196/2019 (see below) do not concern scuba diving.
Diving support vessels or boats must display the marks provided for by international regulations to prevent collisions at sea during diving operations.
Any isolated diver (in a scuba or freediving) must signal his presence by means of a red flag with a white diagonal.
Within a radius of 100 meters around a flag indicating the presence of a diver, an appropriate speed must be maintained at all times to guarantee the safety of the diver; in any case, this speed will be limited to 5 knots.
PREFECTURE OF MARTINIQUE, DECREE 2018/116
Regulating the practice of nautical activities along the coast of the Martinique, of the Guadeloupe and communities of Saint-Barthélemy and Saint-Martin.
The following provisions apply to the practice of scuba diving in a scuba diving suit or in apnea (free diving).
Diving support vessels or boats must display the marks provided for by international regulations to prevent collisions at sea during diving operations.
(...)
Any isolated diver (in a scuba or freediving) must signal his presence by means of a red flag bearing a white St. Andrew's cross or a red flag bearing a white diagonal.
Within a radius of 100 meters around a flag indicating the presence of a diver, an appropriate speed must be maintained at all times to guarantee the safety of the diver; in any event, this speed will be limited to 5 knots.
This provision also applies around a brightly colored buoy indicating the presence of an underwater hunter.
ATLANTIC MARITIME PREFECTURE, ORDER 2018-090
Pleasure craft or craft participating in recreational diving operations must bear the marks provided for by international regulations to prevent collisions at sea.
Lone divers must signal their presence by means of a red flag bearing a white St. Andrew's cross or a red flag bearing a white diagonal.
The navigation of all types of vessels and gear is prohibited within a radius of 100 meters around a sign indicating the presence of divers.
MARITIME PREFECTURE OF THE MANCHE AND THE NORTH SEA, ORDER 41/2018
Ships or boats participating in recreational diving or underwater hunting operations must bear the distinctive marks provided for by the international regulations to prevent collisions at sea referred to above.
Recreational diving or spearfishing must be marked with a red flag bearing the Saint-André cross or a red flag bearing a white diagonal. To ensure visibility, this flag will be hoisted on a buoy.
The presence of a ship or an accompanying craft displaying the distinctive marks mentioned above does not in any way exempt from this obligation.
The navigation of any vessel, craft or floating device not participating in diving operations is prohibited within a radius of 100 meters around a mark indicating the presence of divers. Within the framework of the derogatory regime provided for in article 8 of this decree, the vessels, boats and equipment concerned must as far as possible circulate as far as possible from the mark indicating the presence of divers.
Article 8. Derogatory provisions
The provisions of this decree are not applicable:
- State ships and boats on a rescue or public service mission;
- ships on a rescue or public service mission placed under the operational control of a CROSS;
- ships, machines and people in distress;
- to ships providing prompt assistance.
MAYOTTE PREFECTURE, ORDER 146 / UTM / 2012
People practicing diving mark their presence according to the rules prescribed by the international regulations to prevent collisions at sea, and in particular the ALPHA flag of the international code of signals which must be displayed on support vessels (rigid white and blue flag of at least 0.5 meters in vertical dimension and visible over the entire horizon).
In the absence of an accompanying vessel, the dive is signaled by the red flag bearing a white Saint Andrew's cross or the red flag bearing a white diagonal.
The navigation of all ships and floating devices is prohibited within a radius of one hundred meters around a mark indicating the presence of divers.
When the material conditions of navigation or maneuverability do not allow the prescribed safety radius to be respected, it is the captains of ships and similar vehicles, windsurfers and persons navigating on beach motorized vehicles to take all measures and precautions. necessary so as not to jeopardize the safety of people when diving. In particular, you should drive as far as possible from the mark indicating the presence of divers.
FRENCH POLYNESIA
The activity on the dive sites is materialized by the flag “A” of the international code of signals, in accordance with the maritime regulations in force. However, this flag may not have a luff less than 0.50 meter.
Text: article 8 of decree n ° 199 CM of February 15, 2018
NEW CALEDONIA
In New Caledonia, article 27 of deliberation n ° 307 of August 27, 2002 simply indicates that diving is reported according to the regulations in force.
INLAND WATERS
Article A4241-48-36 of the transport code
Additional marking of vessels used for thedivingunderwater
1. Any boat used for the practice ofdivingunderwater must, in addition to the marking prescribed by the other provisions of this section, bear:
A rigid reproduction, at least 1 m high, of flag “A” of the International Code of Signals, placed in an appropriate place and at a height such that it is visible, night and day, from all directions . For vessels less than 7 m in length, the height of the rigid reproduction of flag A is at least 50 cm in height.
2. Where appropriate, it may, instead of the signage prescribed in paragraph 1 above, carry the signage provided for in paragraph 1 of articleA. 4241-48-34.
All boats must keep a sufficient distance from a boat bearing the signs used for the practice ofdivingunderwater (article A4241-53-39 of the transport code).
HISTORY OF THE RED PAVILION WITH WHITE DIAGONAL

The diagonal white red flag was invented in the early 1950s by an American from Michigan, Denzel James Dockery.
A pioneer of diving, he was looking for a way to make himself known to boats when he was in immersion.
He was inspired by the red flag of the US-Navy indicating a danger and added a white stripe diagonally, the only position available because a red flag with a horizontal white stripe corresponded to the Austrian flag while with a vertical white stripe, it corresponded to the number 7 in the US Navy.
A partir de 1956, la chaîne de magasins US Divers (Ted Dickson) diffusa ce drapeau sur l’ensemble du territoire américain et l’année suivante, en septembre 1957, il fut consacré par un article dans le magazine Skin Diver : le pavillon « plongeur » était né.
© Extract fromPleasure Diving booksby Alain Foret at Editions GAP.
Any reproduction prohibited on any medium whatsoever without the written consent of the publisher and the author.
