Safe water mark
![](http://upload.wikimedia.org/wikipedia/commons/2/20/IALA_safe_water.png)
![](http://upload.wikimedia.org/wikipedia/commons/thumb/e/e0/Limfjord_safe_water_mark.jpg/220px-Limfjord_safe_water_mark.jpg)
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. They usually imply that open, deep and safe water lies ahead. They are also used to indicate the start and end of a buoyed section of a continuous narrow channel; and a series of them may mark a safe route through shallow areas.[1] It is therefore important to consult appropriate charts to determine their meaning in each location. They are also known as fairway buoys and clear water buoys.
They are recognisable by their red-and-white vertical stripes and commonly bear a top sign in shape of a red ball. They either flash Morse code "A" (di-dah), or one long flash, occulting (more light than dark) or isophase (equal light and dark) every 10 seconds (L Fl 10s).[2]
In the United States, safe water marks are printed with the initials of their associated waterways or localities.
See also
![](http://upload.wikimedia.org/wikipedia/en/thumb/4/4a/Commons-logo.svg/30px-Commons-logo.svg.png)
- Navigation
- Lateral mark
- Cardinal mark
- Isolated danger mark
- Special mark
References
Further reading
- "Safe Water Marks" (PDF). IALA. Archived from the original (PDF) on 2007-12-14.