ARPA WRITTEN EXAM – OOD QUESTIONS AND ANSWERS
What controls can be adjusted if known targets are not being detected on radar? - CORRECT
ANSWER✅✅✅Gain, suppressions, range scale
What factors contribute to the assessment of risk of collision? - CORRECT
ANSWER✅✅✅-Relative motion line (CPA/TCPA)
-Aspect
-Error in calculations
When will a radar contact remain stationary on a relative motion radar display? - CORRECT
ANSWER✅✅✅When it is on the same course and speed as your vessel
If a radar contact is dead ahead and the range decreases without a change in bearing, what is the
estimated speed of the contact? - CORRECT ANSWER✅✅✅Dead in the Water (DIW)
If a radar contact is directly astern and the range decreases without a change in bearing, what is
the estimated speed of the contact? - CORRECT ANSWER✅✅✅15 knots
How can the closest point of approach (CPA) of a contact on a relative motion radar be
determined? - CORRECT ANSWER✅✅✅After marking the contact at least twice over a
minute
What is a radar display called when North is always at the top of the screen? - CORRECT
ANSWER✅✅✅Stabilized display
What inputs are needed to maintain a North-Up, True Motion display on radar? - CORRECT
ANSWER✅✅✅Gyro course, speed log
Besides ARPA information, what should an ARPA user consider? - CORRECT
ANSWER✅✅✅-Limitations of the information
-Rules of the road
, -Circumstances and external considerations
In restricted visibility, what should you avoid when altering course for a vessel forward of your
beam? - CORRECT ANSWER✅✅✅Avoid altering course to port except in overtaking
situations
When two ARPA Equipped Ships Collide, What Is Typically True? - CORRECT
ANSWER✅✅✅Both vessels are likely to be found at fault
When Using an ARPA, What Should You Consider to Evaluate Displayed Information? -
CORRECT ANSWER✅✅✅Navigational constraints may require a target vessel to change
course
What Information Is Least Dependent on ARPA Processing? - CORRECT
ANSWER✅✅✅EBL/VRM data
What Speed Indicators Should Provide Inputs to ARPA Equipment According to IMO? -
CORRECT ANSWER✅✅✅The ship's speed through water
Minimum Number of Targets an IMO Approved ARPA Must Track Simultaneously? -
CORRECT ANSWER✅✅✅20
Lowest Range Scale IMO Requires ARPA Facilities to be Available On? - CORRECT
ANSWER✅✅✅3 miles
IMO Standards for ARPA Data Display Visibility? - CORRECT ANSWER✅✅✅Should be
visible to more than 1 observer in light conditions
IMO Requirements for Past Positions Displayed by ARPAs? - CORRECT
ANSWER✅✅✅All ARPAs can display both true and relative past positions
What controls can be adjusted if known targets are not being detected on radar? - CORRECT
ANSWER✅✅✅Gain, suppressions, range scale
What factors contribute to the assessment of risk of collision? - CORRECT
ANSWER✅✅✅-Relative motion line (CPA/TCPA)
-Aspect
-Error in calculations
When will a radar contact remain stationary on a relative motion radar display? - CORRECT
ANSWER✅✅✅When it is on the same course and speed as your vessel
If a radar contact is dead ahead and the range decreases without a change in bearing, what is the
estimated speed of the contact? - CORRECT ANSWER✅✅✅Dead in the Water (DIW)
If a radar contact is directly astern and the range decreases without a change in bearing, what is
the estimated speed of the contact? - CORRECT ANSWER✅✅✅15 knots
How can the closest point of approach (CPA) of a contact on a relative motion radar be
determined? - CORRECT ANSWER✅✅✅After marking the contact at least twice over a
minute
What is a radar display called when North is always at the top of the screen? - CORRECT
ANSWER✅✅✅Stabilized display
What inputs are needed to maintain a North-Up, True Motion display on radar? - CORRECT
ANSWER✅✅✅Gyro course, speed log
Besides ARPA information, what should an ARPA user consider? - CORRECT
ANSWER✅✅✅-Limitations of the information
-Rules of the road
, -Circumstances and external considerations
In restricted visibility, what should you avoid when altering course for a vessel forward of your
beam? - CORRECT ANSWER✅✅✅Avoid altering course to port except in overtaking
situations
When two ARPA Equipped Ships Collide, What Is Typically True? - CORRECT
ANSWER✅✅✅Both vessels are likely to be found at fault
When Using an ARPA, What Should You Consider to Evaluate Displayed Information? -
CORRECT ANSWER✅✅✅Navigational constraints may require a target vessel to change
course
What Information Is Least Dependent on ARPA Processing? - CORRECT
ANSWER✅✅✅EBL/VRM data
What Speed Indicators Should Provide Inputs to ARPA Equipment According to IMO? -
CORRECT ANSWER✅✅✅The ship's speed through water
Minimum Number of Targets an IMO Approved ARPA Must Track Simultaneously? -
CORRECT ANSWER✅✅✅20
Lowest Range Scale IMO Requires ARPA Facilities to be Available On? - CORRECT
ANSWER✅✅✅3 miles
IMO Standards for ARPA Data Display Visibility? - CORRECT ANSWER✅✅✅Should be
visible to more than 1 observer in light conditions
IMO Requirements for Past Positions Displayed by ARPAs? - CORRECT
ANSWER✅✅✅All ARPAs can display both true and relative past positions
