What does a yellow X topmark mean?
It's an IALA special mark: a yellow buoy showing a special area or feature, not a channel edge.
Special marks point out something on the chart or in the sailing directions: spoil grounds, military exercise areas, cables, pipelines, outfalls, water-ski zones, data buoys. Look it up on the chart to see what it marks and whether you can pass it.
- Colour: yellow. Topmark (if any): a single yellow X.
- Light (if any): yellow, with any rhythm not used for white lights, e.g. Fl Y.
- Shape is optional; at a channel edge it may take the matching lateral shape.
- Don't confuse it with the yellow upright cross on a blue and yellow emergency wreck buoy.
Source: IALA Maritime Buoyage System, special marks.
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In IALA Region A, what colour and shape is a port-hand mark?
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