1044-1188)

II SÉRIE-A — NÚMER0 44

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 13) 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; and

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) Of 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

17 — A thorough understanding should be attained of the relationship of the International Regulations for Preventing Collisions at Sea 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.

Training and assessment in the operational use ' of automatic radar plotting aids (ARPA)

18 — Training and assessment in the operational use of automatic radar plotting aids (ARPA) should:

1) Require prior completion of the training in radar observation and plotting or combine that training with the training given in paragraphs 19 to 36 below;