Safe water mark

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Examples of Safe Water Marks
An example of a Safe Water Mark in Limfjord, Denmark

A Safe Water Mark, as defined by the International Association of Lighthouse Authorities, is a sea mark used in maritime pilotage to indicate the end of a channel. It usually implies that open, deep and safe water lies ahead, though it is sometimes also used to indicate the start and end of a buoyed section of a continuous narrow channel, or a line of these marks can be used to mark a safe route through shallow areas.[1] It is therefore important to consult an appropriate chart to determine the exact meaning in each case. The marker is also sometimes known as a Fairway Buoy.

It is recognisable by its red and white vertical stripes and commonly bears a top-sign in shape of a red ball. Lighted buoys flash morse code "A", occulting (more light than dark), Isophase (equal light and dark) or long flash every 10 seconds (L Fl 10s).[2]

In the United States, safe water marks have the initials of their associated waterways or localities printed on them.

Lighted buoy flashes morse code "T" (one long flash) with intervals of 6 seconds

See also[edit]


  • "Safe Water Marks" (PDF). IALA. Archived from the original (PDF) on 2007-12-14.
  1. ^ NOAA Chart 37222. See the vicinity of "Hubertgat"
  2. ^ Haire, Penny.Yachtmaster. Royal Yachting Association, 2009, p. 61.