(excerpt from Regulations about way of marking of waterways and aids to navigation)
The isolated danger mark has the shape of a pillar or spar painted in black with one or more broad horizontal red bands.
The isolated danger mark must have a topmark, two clearly noticable mutually separated black spheres placed one above the other.
The light of the isolated danger mark is a white flashing light, with two flashes of light in a group.
The isolated danger mark can be passed from all sides.
NAUTICAL CHARACTERISTICS OF ISOLATED DANGER MARKS
|Isolated danger marks
||Black with one or more broad horizontal red bands
||Any, but different from lateral marks (pillar or spar preferred)
||2 black spheres, one above the other
|Light (if any)
||Group flashing (2)