- Setting Up and Maintaining Displays (1.0 hour)
sets up an appropriate display presentation for the required task and current situation (stabilised relative motion and true motion displays)
adjusts radar controls for the optimum display of echoes
uses log and gyro compass inputs
manually selects, acquires and monitors critical targets
sets up automatic acquisition and exclusion areas
uses the appropriate time scale for vectors or graphics to produce information required
identifies differences between information shown in sea stabilised mode and the ground stabilised mode
selects the appropriate mode for the circumstances
sets up echo-referencing in the true motion mode
- Obtaining target information (1.0 hour)
operates display in true and relative modes to obtain true and relative vectors in each display mode
states the benefits of switching between true and relative vectors
uses the graphic display of PPC's and PAD's
determines threat of collision by forward extrapolation of vectors and by the use of PAD's
uses targets history display
uses trial manoeuvres are (approximations depending on the model of ownship manoeuvring characteristics)
refers to the equipment manual for a description of the manoeuvring characteristics model used
sets and acknowledges operational warnings
states benefits and limitations of operational warnings
sets area rejection boundaries to avoid spurious interference
- Errors of Interpretation (1 hour)
identifies consistently vectors in the wrong mode (a common error)
derives information from vectors with numeric display
explains and re-acquired "lost target" may temporarily shown a course and speed suggesting an alteration when none has occurred
states data from PADs and PPCs displayed apply only to "own ship" and targets and do not indicate mutual threats between targets
states that the length of line from target to PAD or PPC is not an indicator of target speed
states that history displays may not be in same mode as vectors
states that a change of direction in the relative history display does not necessarily imply that the target has altered course
explains that the incorrect interpretation of ARPA can lead to a dangerous misunderstanding
- Errors in Displayed Data ( 2.5 hours)
identifies bearing errors in the radar installation by:
Backlash
ship motion
asymmetrical antenna beam
azimuth quantisation
explains errors in range generated by:
rolling of "own ship"
range quantisation
explains that unreliable indications are given when smoothing filter in the tracker combined with alteration in "own ship's" course/speed
explains the effects of heading and speed errors on derived information
states that the smoothness of the displayed history track is an indication of satisfactory tracking by ARPA
- System Operational Tests (1.5 hour)
uses self-diagnostic routines
operates test programmes to check performance against known solutions
demonstrates performance checks, including trial manoeuvre by manual plotting
takes correct action malfunction of ARPA
- Risks of Over-reliance on ARPA (3 hour)
demonstrates the use of ARPA explains the need to comply with basic principles in keeping a navigational watch
reacts correctly to operational alarms
avoids small predicted passing distances (CPA and bow crossing ranges)
explains that sensor input alarms only operate on failure of input and do not respond to inaccurate input
- Obtaining Information from ARPA Displays (6 hours)
obtains information in both true and relative modes
identifies critical targets
determines relative course and speed of target
determines CPA and TCPA of target
determines true course and speed of target
uses displays of past positions for detecting changes in course or speed of target
uses trial manoeuvre facility to check validity of intended alteration of course or speed
- Application of COLREG 1972 (8 hours)
takes correct action to avoid close-quarters situations or potential collision situations
monitors subsequent situation and resumes original course and speed when safe to do so