Special marks

Special marks indicate special areas or features: exercise zones, cables and pipelines, spoil grounds, aquaculture, data buoys (ODAS), anchorage limits. They are yellow, show a yellow light with a rhythm different from the white lights, and carry a topmark in the shape of a yellow diagonal cross “X”.

Yellow with a lying cross “X”: this is not a channel, it is a special area. Check the chart.

Special mark

Colour: yellow
Buoy shape: pillar or spar
Topmark: a diagonal cross “X”
Light: yellow, any rhythm (other than those reserved for white lights) A yellow light with a rhythm different from the white lights, so they cannot be confused.
What it means: Marks a special area or feature. Check the chart and publications for its exact meaning.

Facts per the IALA Maritime Buoyage System (MBS ed. 2.0). The drawings are our own vectors. The light rhythm and colour in the drawing are illustrative: check the real characteristics of a specific buoy on the chart and in the list of lights.