It is generally accepted nowadays that, to obtain full value for anti-collision purposes from the use of radar by a ship proceeding in poor visibility, it is necessary to plot, or to compute in some other way, the raw data which may be obtained from the radar. It is also usually conceded that, for this to be done effectively in frequented areas, without the aid of mechano/electronic devices, a great deal of time and expertise is demanded from the radar observer and a great deal of responsibility thereby rests upon his shoulders.

To reduce the load of work and the possibility of human error and to give the observer more time to use his intelligence in appraising the situation and keeping it under review, radar engineers are already pressing forward the development of automatic devices which, in one way or another, produce computed informatioa in the form ultimately needed.