Special marks

A special mark indicates an area or feature whose nature appears in a chart or associated nautical publication. Yellow can relate to data acquisition, aquaculture, a cable, exercise or recreational area among documented examples. It does not automatically mean “pass to starboard” or “deep water”. The figure relates a yellow body and diagonal X to purpose examples without an approach track. The aim is to understand why the published description forms part of useful identity. The same visible category can serve different purposes whose local implications need separate information.

The body is yellow and any fitted light yellow. The topmark, where present, is a yellow X, a diagonal cross distinct from the emergency upright cross. Body form is optional but must not conflict with laterals. On a channel’s port side, for example, a can can avoid confusion that a cone would create; this does not turn yellow into a red or green lateral. Published purpose continues to distinguish special from ordinary lateral identity. Geometry and colour jointly help recognition, while practical placement belongs to the competent authority.