The safe water mark does not mark a danger. It says there is navigable water all around: it can be a mid-channel mark, a landfall mark or a channel entrance mark. It has red and white vertical stripes, a single red ball as a topmark, and a white light: isophase, occulting, one long flash every 10 s, or Morse „A”.
Vertical red and white stripes and a single red ball: it is safe here, you may approach.
Safe water mark
Colour
vertical stripes: red, white, red, white
Buoy shape
spherical
Topmark
a single ball
Light
Iso, Oc, LFl.10s or Morse „A” (● ▬)White: isophase, occulting, one long flash every 10 s, or Morse „A”. Below: one long flash.
What it means
Navigable water all around the mark. You may pass it on either side.
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.