A buoy to be left on your port hand when approaching from seaward or in the direction of the Main Flood tide. Where the flood tide flows in a variety of directions, a conventional direction may be decreed and will be shown on the chart. Beware of the fact that you can rely on this information only where IALA System A applies, so if you are travelling far and you arrive in System B waters you can either make your approach astern or reverse the information.