C33 EXAM QUESTIONS AND ANSWERS
GRADED A+ 2025/2026
Which of the following is correct about frequency modulation? - ANS the frequency is
constant
When an engineer on duty is inspecting an UMS-mode operated engine room at night what
precaution should be taken? - ANS switch on the dead man alarm upon entering the control
room
Where should the GMDSS radio log be kept on board ship? - ANS At the GMDSS operating
position
Which statement about transmitting distress messages by radiotelephone is incorrect? -
ANS It is advisable to follow a distress message on 2182 kHz by two dashes of 10 to 15
seconds duration
What is understood by the assigned frequency? - ANS the upper side band (USB)
Who operates as marine traffic monitoring and communications systems, providing navigational
information and the tracking of vessel movements within the port limits? - ANS VTS
Which of the following types/sizes of vessels in international trade do not need to be fitted with
a radiotelephone station? - ANS Cargo ships below 300 tons gross
1 @COPYRIGHT 2025/2026 ALLRIGHTS RESERVED.
,The "squelch" adjustment on the front panel of a mariphone serves to ? - ANS adjust the
noise threshold of the mariphone receiver
This communication system is used for distress alert, transmission and reception of maritime
safety information via enhanced group calls. This may also be used for general communications
- ANS Satcom C
Where does a long distance communication in the HF-bands depends on - ANS Satellites
Moored in a harbour, transmitting with a mariphone is on what regulation - ANS not allowed
The squelch on the control panel of a VHF-sat serves to - ANS adjust the threshold level for
admitting signals and refusing noise
How does the prefix PAN indicates in radiotelephone communications - ANS a calling station
has an urgent message about the safety of a person
When may a compulsory vessel not be allowed to leave port - ANS When the vessel has
replaced a required piece of GMDSS - related equipment but its performance has not been
verified or logged
Which of the following is the full name of abbreviation VDR? - ANS Voyage data recorder
How should the letter "D" be pronounced when spoken on the radiotelephone? - ANS DELL
TAH
You see an iceberg that has not been reported. What kind of radio message do you transmit to
warn others? - ANS Safety message
2 @COPYRIGHT 2025/2026 ALLRIGHTS RESERVED.
, A VHF transmission range is mainly restricted of which items on the list - ANS the curvature
of the surface of the earth
Which one on the list is required before a mariphone is installed on board ? - ANS a license
must be issued
At what temperature in degree Celsius will safety devices called fusible plug installed in air
compressor or compressed air system melts in order to prevent explosion? - ANS 100
What does MUF stand for? - ANS highest possible frequency that will be reflected by the
ionosphere
By non-reduced transmitting power in VHF how many power in watt should be require? -
ANS 5 - 10 watt
Which of the following is a homing device to enable ships and SAR aircraft to accurately pinpoint
a ship in distress position ? - ANS SART
Which one of the following report if an incident takes place involving the discharge or probable
discharge of oil ?(Annex I of MARPOL 73/78). - ANS harmful substances report
What should you do FIRST to correct a condition wherein a diesel engine is operating with
excessively high exhaust temperature on all cylinders ? - ANS Reduce the engine load
Which channel and mode should be used when initiating a Distress alert transmission? -
ANS Channel 70 DSC
Which signal is used by a rescue unit to indicate"Avast hauling"? - ANS Firing of a red star
signal
Why does a radio waves used in satellite communication are not affected by ionosphere? -
ANS TDM-signals are used
3 @COPYRIGHT 2025/2026 ALLRIGHTS RESERVED.
GRADED A+ 2025/2026
Which of the following is correct about frequency modulation? - ANS the frequency is
constant
When an engineer on duty is inspecting an UMS-mode operated engine room at night what
precaution should be taken? - ANS switch on the dead man alarm upon entering the control
room
Where should the GMDSS radio log be kept on board ship? - ANS At the GMDSS operating
position
Which statement about transmitting distress messages by radiotelephone is incorrect? -
ANS It is advisable to follow a distress message on 2182 kHz by two dashes of 10 to 15
seconds duration
What is understood by the assigned frequency? - ANS the upper side band (USB)
Who operates as marine traffic monitoring and communications systems, providing navigational
information and the tracking of vessel movements within the port limits? - ANS VTS
Which of the following types/sizes of vessels in international trade do not need to be fitted with
a radiotelephone station? - ANS Cargo ships below 300 tons gross
1 @COPYRIGHT 2025/2026 ALLRIGHTS RESERVED.
,The "squelch" adjustment on the front panel of a mariphone serves to ? - ANS adjust the
noise threshold of the mariphone receiver
This communication system is used for distress alert, transmission and reception of maritime
safety information via enhanced group calls. This may also be used for general communications
- ANS Satcom C
Where does a long distance communication in the HF-bands depends on - ANS Satellites
Moored in a harbour, transmitting with a mariphone is on what regulation - ANS not allowed
The squelch on the control panel of a VHF-sat serves to - ANS adjust the threshold level for
admitting signals and refusing noise
How does the prefix PAN indicates in radiotelephone communications - ANS a calling station
has an urgent message about the safety of a person
When may a compulsory vessel not be allowed to leave port - ANS When the vessel has
replaced a required piece of GMDSS - related equipment but its performance has not been
verified or logged
Which of the following is the full name of abbreviation VDR? - ANS Voyage data recorder
How should the letter "D" be pronounced when spoken on the radiotelephone? - ANS DELL
TAH
You see an iceberg that has not been reported. What kind of radio message do you transmit to
warn others? - ANS Safety message
2 @COPYRIGHT 2025/2026 ALLRIGHTS RESERVED.
, A VHF transmission range is mainly restricted of which items on the list - ANS the curvature
of the surface of the earth
Which one on the list is required before a mariphone is installed on board ? - ANS a license
must be issued
At what temperature in degree Celsius will safety devices called fusible plug installed in air
compressor or compressed air system melts in order to prevent explosion? - ANS 100
What does MUF stand for? - ANS highest possible frequency that will be reflected by the
ionosphere
By non-reduced transmitting power in VHF how many power in watt should be require? -
ANS 5 - 10 watt
Which of the following is a homing device to enable ships and SAR aircraft to accurately pinpoint
a ship in distress position ? - ANS SART
Which one of the following report if an incident takes place involving the discharge or probable
discharge of oil ?(Annex I of MARPOL 73/78). - ANS harmful substances report
What should you do FIRST to correct a condition wherein a diesel engine is operating with
excessively high exhaust temperature on all cylinders ? - ANS Reduce the engine load
Which channel and mode should be used when initiating a Distress alert transmission? -
ANS Channel 70 DSC
Which signal is used by a rescue unit to indicate"Avast hauling"? - ANS Firing of a red star
signal
Why does a radio waves used in satellite communication are not affected by ionosphere? -
ANS TDM-signals are used
3 @COPYRIGHT 2025/2026 ALLRIGHTS RESERVED.
