ABSTRACT
The marine radar is the piece of equipment on the ship’s bridge that is perhaps most used by the OOW when carrying out a safe navigational watch. A mandatory aid to navigation, the radar is used for the identifying, tracking (with integrated ARPA) and the positioning of vessels (including one’s own vessel). The marine radar is classified either under the x-band (10 GHz) or S-band (3 GHz) frequencies. The x-band, being of higher frequency than the S-band, is used for a sharper image and better resolution whereas the S-band is predominantly when visibility is poor such as during heavy rain or fog or when vessel identification and tracking is required. Ship-tracking devices are compulsory under the COLREGS. SOLAS Chapter 5, regulation 19 states that
all ships of 3,000 gross tonnes and upwards shall, in addition to meeting the requirements of paragraph 2.5, have a 3 GHz radar or where considered appropriate by the Administration, a second 9 GHz radar, or other means to determine and display the range and bearing of other surface craft, obstructions, buoys, shorelines and navigational marks to assist in navigation and in collision avoidance, which are functionally independent of those referred to in paragraph.
With the help of marine radar, accidents can be prevented at sea by determining the closest point of approach (CPA) and the time to closest point of approach (TCPA), electronic bearing line (EBL), variable range marker (VRM), and so forth. The benefit of radar does not stop when the ship is no longer at sea. Even alongside or within port confines, radar can be used to monitor traffic at short range. The marine radar has a screen (referred to as the Plan Position Indicator (PPI)) which displays all the targets that are present within the radar range. Since these objects are clearly visible on the screen, navigating and monitoring the position of the ship is vastly improved.