RADAR and ARPA Flashcards
Who must carry RADAR?
Ships of 300gt and all passanger ships must carry a 9GHz radar (SOLAS chV)
Ships over 3000gt must carry two radar.
Typically 1 for anti-collision and 1 for navigation.
What considerations should the operator give to info provided by radar?
Small vessels. ice floes etc may not be detected.
Echoes may be obstructed by sea or rain clutter.
What are the blind spots and shadow sectors.
Range setting considered along with traffic density and speed of own ship.
How often should performance monitor be run?
Prior to sailing.
Once a watch while radar watch is being maintained.
What checks should be carried out on a radar?
Performance monitoring.
Heading marker alignment.
VRM and EBL accuracy.
Confirm settings.
What are the Radar’s modes of operation?
Unstabilised.
True motion sea stabilised.
True motion ground stabilised.
Relative motion head up unstabilised.
Relative motion course up sea/ground stabilised.
Relative motion north up sea/ground stabilised.
Describe true motion sea stabilised.
Ship’s position not at the centre.
Moves in direction and at speed of vessel accross display.
Resets to original position when reaches edge.
Requires compass and speed input.
Moving targets move.
Stationary targets are stationary.
If a fixed target is moving then set and rate can be calc’d.
Used for collision avoidance due to use of relative distance.
Describe true motion ground stabilised.
Ship’s position not at the centre.
Moves in direction and at speed of vessel accross display.
Resets to original position when reaches edge.
Requires compass and speed input.
Moving targets move.
Stationary targets are stationary.
Used for navigation due to use of absolute distance.
Describe relative motion head up unstabilised.
Ship’s position at the centre.
000° represents ship’s head (unstabilised).
Display mirrors what is happening out of the window which improves situational awareness.
Disorientation can occur when transfering postion to chart or when altering course.
No compass input.
Relative bearings with EBL.
Stationary targets move at own ship’s speed and in reciprocal direction.
Moving targets movement is the resultant of own ship’s and their ships course and speed.
Describe relative motion course up sea/ground stabilised.
Ship’s position at the centre.
Ship’s heading replaces 000°.
Disorientation can occur when transfering postion to chart or when altering course.
Heading input required from compass.
True bearings with EBL.
Stationary targets move at own ship’s speed and in reciprocal direction.
Moving targets movement is the resultant of own ship’s and their ships course and speed.
Can be used for collision avoidance or navigation, depending on which form of stabilisaiton is used.
Describe relative motion north up sea/ground stabilised.
Ship’s position at the centre.
000° is North (T).
Heading marker points at course.
No disorientation when comparing with chart.
No disorientation due echoes on actual positions
Heading input required from compass.
True bearings with EBL.
Stationary targets move at own ship’s speed and in reciprocal direction.
Moving targets movement is the resultant of own ship’s and their ships course and speed.
Can be used for collision avoidance or navigation, depending on which form of stabilisaiton is used.
What is the difference betwen sea and ground stabilised?
Ground requires input from GPS and water log.
Sea requires input from gyro.
Ground is used for approaches to fixed objects.
Sea is used for cllision avoidance.
What inputs are required for ARPA?
Heading (gyro).
Speed (log).
What alarms can be set on ECDIS?
Safety depth.
Safety contour.
What are ENCs?
Produced by IHO.
Vector charts.
Database.
Displayed as a seamless chart.
Layered.
Categories of data can be deselected (ie textual descriptions).
Alarms can be set (ie safety depth or contour).
What are RNC?
Facsimile of paper chart.
Raster charts.
Not layered.
No alarms.
