IALA Special Marks
Yellow marks indicating special areas such as ODAS, traffic separation, military exercise areas, or cables/pipelines.
Special marks indicate a special area or feature referred to in nautical publications. They are not primarily intended to assist navigation.
- Colour: yellow - Topmark: single yellow X-shape (St. Andrew's cross) - Light: yellow, any rhythm not used for other marks - Shape: optional — any shape not conflicting with lateral or safe water marks
Examples include: ocean data acquisition systems (ODAS), traffic separation marks, spoil ground marks, military exercise zone marks, cable or pipeline marks, recreation zone marks.
Key Takeaways
All yellow colour scheme
X-shaped (cross) topmark in yellow
Yellow light distinguishes from navigation marks
Indicates special areas — check nautical publications for details
Common Mistakes
Assuming special marks indicate a navigational hazard
Not consulting charts/publications for what the mark indicates
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