Training and Assessment in Radar Observation and Plotting footnote
Clasification Society 2024 - Version 9.40

Training and Assessment in Radar Observation and Plotting footnote

  2 Training and assessment in radar observation and plotting should:

  • .1 incorporate the use of radar simulation equipment; and

  • .2 conform to standards not inferior to those given in paragraphs 3 to 17 below.

3 Demonstrations of and practice in radar observation should be undertaken, where appropriate, on live marine radar equipment, including the use of simulators. Plotting exercises should preferably be undertaken in real time, in order to increase trainees’ awareness of the hazards of the improper use of radar data and improve their plotting techniques to a standard of radar plotting commensurate with that necessary for the safe execution of collision-avoidance manoeuvring under actual seagoing conditions.

General

Factors affecting performance and accuracy

4 An elementary understanding should be attained of the principles of radar, together with a full practical knowledge of:

  • .1 range and bearing measurement, characteristics of the radar set which determine the quality of the radar display, radar antennae, polar diagrams, the effects of power radiated in directions outside the main beam, a non-technical description of the radar system, including variations in the features encountered in different types of radar set, performance monitors and equipment factors which affect maximum and minimum detection ranges and accuracy of information;

  • .2 the current marine radar performance specification adopted by the Organizationfootnote;

  • .3 the effects of the siting of the radar antenna, shadow sectors and arcs of reduced sensitivity, false echoes, effects of antenna height on detection ranges and of siting radar units and storing spares near magnetic compasses, including magnetic safe distances; and

  • .4 radiation hazards and safety precautions to be taken in the vicinity of antennae and open waveguides.

Detection of misrepresentation of information, including false echoes and sea returns

5 A knowledge of the limitations to target detection is essential, to enable the observer to estimate the dangers of failure to detect targets. The following factors should be emphasized:

  • .1 performance standard of the equipment;

  • .2 brilliance, gain and video processor control settings;

  • .3 radar horizon;

  • .4 size, shape, aspect and composition of targets;

  • .5 effects of the motion of the ship in a seaway;

  • .6 propagation conditions;

  • .7 meteorological conditions; sea clutter and rain clutter;

  • .8 anti-clutter control settings;

  • .9 shadow sectors; and

  • .10 radar-to-radar interference.

6 A knowledge should be attained of factors which might lead to faulty interpretation, including false echoes, effects of nearby pylons and large structures, effects of power lines crossing rivers and estuaries, echoes from distant targets occurring on second or later traces.

7 A knowledge should be attained of aids to interpretation, including corner reflectors and radar beacons; detection and recognition of land targets; the effects of topographical features; effects of pulse length and beam width; radar-conspicuous and -inconspicuous targets; factors which affect the echo strength from targets.

Practice

Setting up and maintaining displays

8 A knowledge should be attained of:

  • .1 the various types of radar display mode; unstabilized ship’s-head-up relative motion; ship’s-head-up, course-up and north-up stabilized relative motion and true motion;

  • .2 the effects of errors on the accuracy of information displayed; effects of transmitting compass errors on stabilized and true-motion displays; effects of transmitting log errors on a true-motion display; and the effects of inaccurate manual speed settings on a true-motion display;

  • .3 methods of detecting inaccurate speed settings on true-motion controls; the effects of receiver noise limiting the ability to display weak echo returns, and the effects of saturation by receiver noise, etc.; the adjustment of operational controls; criteria which indicate optimum points of adjustment; the importance of proper adjustment sequence, and the effects of maladjusted controls; the detection of maladjustments and corrections of:

    • .3.1 controls affecting detection ranges; and

    • .3.2 controls affecting accuracy;

  • .4 the dangers of using radar equipment with maladjusted controls; and

  • .5 the need for frequent regular checking of performance, and the relationship of the performance indicator to the range performance of the radar set.

Range and bearing

9 A knowledge should be attained of:

  • .1 the methods of measuring ranges; fixed range markers and variable range markers;

  • .2 the accuracy of each method and the relative accuracy of the different methods;

  • .3 how range data are displayed; ranges at stated intervals, digital counter and graduated scale;

  • .4 the methods of measuring bearings; rotatable cursor on transparent disc covering the display, electronic bearing cursor and other methods;

  • .5 bearing accuracy and inaccuracies caused by parallax, heading marker displacement, centre maladjustment;

  • .6 how bearing data are displayed; graduated scale and digital counter; and

  • .7 the need for regular checking of the accuracy of ranges and bearings, methods of checking for inaccuracies and correcting or allowing for inaccuracies.

Plotting techniques and relative-motion concepts

10 Practice should be provided in manual plotting techniques, including the use of reflection plotters, with the objective of establishing a thorough understanding of the interrelated motion between own ship and other ships, including the effects of manoeuvring to avoid collision. At the preliminary stages of this training, simple plotting exercises should be designed to establish a sound appreciation of plotting geometry and relative-motion concepts. The degree of complexity of exercises should increase throughout the training course until the trainee has mastered all aspects of the subject. Competence can best be enhanced by exposing the trainee to real-time exercises performed on a simulator or using other effective means.

Identification of critical echoes

11 A thorough understanding should be attained of:

  • .1 position fixing by radar from land targets and sea marks;

  • .2 the accuracy of position fixing by ranges and by bearings;

  • .3 the importance of cross-checking the accuracy of radar against other navigational aids; and

  • .4 the value of recording ranges and bearings at frequent, regular intervals when using radar as an aid to collision avoidance.

Course and speed of other ships

12 A thorough understanding should be attained of:

  • .1 the different methods by which course and speed of other ships can be obtained from recorded ranges and bearings, including:

    • .1.1 the unstabilized relative plot;

    • .1.2 the stabilized relative plot; and

    • .1.3 the true plot; and

  • .2 the relationship between visual and radar observations, including detail and the accuracy of estimates of course and speed of other ships, and the detection of changes in movements of other ships.

Time and distance of closest approach of crossing, meeting or overtaking ships

13 A thorough understanding should be attained of:

  • .1 the use of recorded data to obtain:

    • .1.1 measurement of closest approach distance and bearing;

    • .1.2 time to closest approach; and

  • .2 the importance of frequent, regular observations.

Detecting course and speed changes of other ships

14 A thorough understanding should be attained of:

  • .1 the effects of changes of course and/or speed by other ships on their tracks across the display;

  • .2 the delay between change of course or speed and detection of that change; and

  • .3 the hazards of small changes as compared with substantial changes of course or speed in relation to rate and accuracy of detection.

Effects of changes in own ship’s course or speed or both

15 A thorough understanding of the effects on a relative-motion display of own ship’s movements, and the effects of other ships’ movements and the advantages of compass stabilization of a relative display.

16 In respect of true-motion displays, a thorough understanding should be attained of:

  • .1 the effects of inaccuracies of:

    • .1.1 speed and course settings; and

    • .1.2 compass stabilization data driving a stabilized relative-motion display;

  • .2 the effects of changes in course or speed or both by own ship on tracks of other ships on the display; and

  • .3 the relationship of speed to frequency of observations.

Application of the International Regulations for Preventing Collisions at Sea, 1972, as amended

17 A thorough understanding should be attained of the relationship of the International Regulations for Preventing Collisions at Sea, 1972, as amended to the use of radar, including:

  • .1 action to avoid collision, dangers of assumptions made on inadequate information and the hazards of small alterations of course or speed;

  • .2 the advantages of safe speed when using radar to avoid collision;

  • .3 the relationship of speed to closest approach distance and time and to the manoeuvring characteristics of various types of ships;

  • .4 the importance of radar observation reports and radar reporting procedures being well defined;

  • .5 the use of radar in clear weather, to obtain an appreciation of its capabilities and limitations, compare radar and visual observations and obtain an assessment of the relative accuracy of information;

  • .6 the need for early use of radar in clear weather at night and when there are indications that visibility may deteriorate;

  • .7 comparison of features displayed by radar with charted features; and

  • .8 comparison of the effects of differences between range scales.

Parent topic: Section B-I/12 Guidance regarding the use of simulators
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