An Emergency wreck buoy is used to warn of a new wreck which has not yet been listed in maritime documents. The buoy is expected to be deployed for the first 24-72 hours after the wreck occurs. After that time more permanent buoyage (such as isolated danger marks or cardinal marks) should be deployed and charts updated.[1]
The buoy is designed to "provide a clear and unambiguous"[1] mark of a new and uncharted danger. The buoy is painted with 4, 6 or 8 vertical stripes of alternate yellow and blue. In addition it may have the word "WRECK" painted on it. Optionally it may carry a vertical (St. George's) cross painted yellow. The light flashes alternate yellow and blue for one second each with a half second gap between. No other navigation mark uses blue.[2]
^Maritime buoyage system and other aids to navigation, IALA (International Association of Maritime Aids to Navigation and Lighthouse Authorities), 2010, p. 18