Emergency wreck marking buoy

A new danger (for example a fresh wreck) is marked temporarily with an emergency wreck marking buoy. It has blue and yellow vertical stripes (4 to 8), a topmark in the shape of an upright yellow cross, and an alternating blue and yellow light.

Blue and yellow stripes with an alternating blue-yellow light: a fresh danger that may not be on your chart yet.

Emergency wreck marking buoy

Colour: vertical stripes: blue, yellow, blue, yellow, blue, yellow
Buoy shape: pillar or spar
Topmark: an upright cross
Light: Al.Oc.BuY.3s (blue and yellow alternating, 1 s each, 0.5 s pauses) A blue flash of 1 s, a pause, a yellow flash of 1 s, a pause. Alternating.
What it means: Marks a new danger. Keep well clear and check navigational warnings for the details.

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.