Pilotage is the name given to the navigation of inshore waters and channels by the use of buoys, beacons, leading marks or lights and topographical features in conjunction with the chart, pilot book, compass and echo sounder. It usually demands concentration and attention to detail on the part of the navigator, as well as a complete knowledge of the meaning of various types of buoys and beacons.
Leading Marks and Lights
Leading marks and lights are set up in pairs on or near the shore, the inshore mark is always behind and above the other. They indicate a safe channel or approach to a harbour when they are in transit. By day they are clearly visible marks in a distinctive colour. They may be lit at night with lights of the same or different characteristics and shown on the chart thus "Lights in Line 353o", this being the true bearing of the transit from seaward.
A single leading light or sectored light may sometimes be used, in which case it will normally be split into three adjacent sectors, the centre safe sector white, the port sector red and the starboard sector green. When beating against the wind in an approach channel, the change of colour from white to red or white to green gives a perfect warning of when to change tack, particularly when at some distance from the light source.