Isolated danger mark

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Examples of Isolated Danger Marks

An Isolated Danger Mark, as defined by the International Association of Lighthouse Authorities, is a sea mark used in maritime pilotage to indicate a hazard to shipping such as a partially submerged rock.

Isolated Danger Mark near Hvar, Croatia

It is recognisable by its black and red bands and top-mark of two black balls.

Its distinctive sequence of flashing white light consists of 2 quick flashes with intervals of 5 seconds.

See also[edit]


  • "Isolated Danger Marks" (PDF). IALA. Archived from the original (PDF) on 2007-12-14.