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DG Exit Exam
Answer Key

OCTCO/OCTF exit exam questions and answers — Set 2 — Oil and Chemical Tanker Cargo Operations

Set 2 of the Oil and Chemical Tanker Cargo Operations (OCTCO/OCTF) exit exam bank — 30 of 802 questions, with the correct option marked and a one-line explanation for every one. Read it end to end, jump to a single set, or search it — then sit the same bank as a timed paper. The real DG Shipping exit exam is 30 marks with 15 to pass.

These are the bank's original groupings. Practising deals the whole bank out again every time you reshuffle, so a practice “Set 3” is a different 30 questions each time — the set numbers below are the source file's, and are only used here so the key stays navigable. Options are listed in their original order with fixed letters; when you practise, those move too.

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Set 2 — 30 OCTCO/OCTF exit exam questions with answers

1. What is the purpose of flame screens fitted on tank vent outlets?

  • A. Keep birds out
  • B. Prevent passage of external sparks/flames into cargo tank vapor space
  • C. Stop liquid splash
  • D. Filter dust
Answer: B — Prevent passage of external sparks/flames into cargo tank vapor space
Fine wire gauze dissipates flame heat below ignition temperature, stopping flame entry.

2. What does SOPEP stand for?

  • A. Standard Operational Protocol
  • B. Shipboard Oil Pollution Emergency Plan
  • C. System for Oil Prevention
  • D. Safety Officer Program
Answer: B — Shipboard Oil Pollution Emergency Plan
SOPEP is a mandatory onboard plan detailing emergency responses to oil spills.

3. What is ullage in a cargo tank?

  • A. Distance from liquid surface up to reference point at top of sounding pipe
  • B. Engine room air volume
  • C. Total cargo weight
  • D. Depth of liquid
Answer: A — Distance from liquid surface up to reference point at top of sounding pipe
Ullage measures empty height above liquid level; Sounding measures liquid height from bottom.

4. Why must cargo manifolds be fitted with blank flanges bolted with full set of bolts when not in use?

  • A. Provide positive secondary liquid/vapor containment against valve leakage
  • B. Keep manifold painted
  • C. Weight balance
  • D. Improve appearance
Answer: A — Provide positive secondary liquid/vapor containment against valve leakage
Blank flanges with complete bolting prevent accidental oil spills if valves seep.

5. What is the primary cause of sloshing damage in partially filled cargo tanks?

  • A. Pump suction
  • B. Inert gas fan vibration
  • C. High cargo temp
  • D. Violent movement of liquid cargo creating severe dynamic impact pressures against bulkheads
Answer: D — Violent movement of liquid cargo creating severe dynamic impact pressures against bulkheads
Sloshing forces in partially filled slack tanks can damage internal bulkheads and heating coils.

6. What equipment measures oil content in water discharging from bilges or slop tanks?

  • A. Thermometer
  • B. Flow meter
  • C. Tachometer
  • D. Oil Content Meter (OCM) / 15 ppm alarm
Answer: D — Oil Content Meter (OCM) / 15 ppm alarm
OCMs monitor oil concentration in discharge water under MARPOL limits.

7. What precaution must be observed when taking manual oil soundings on an inerted tanker?

  • A. Use nylon rope
  • B. Use vapor-lock valves and metallic sounding tapes properly grounded/bonded to ship structure
  • C. Open main hatch wide
  • D. Stand barefoot
Answer: B — Use vapor-lock valves and metallic sounding tapes properly grounded/bonded to ship structure
Grounding sounding tapes prevents static sparks inside cargo vapor spaces during dips.

8. What is the function of cargo tank heating coils on oil tankers?

  • A. Wash tank walls
  • B. Boil cargo into gas
  • C. Cool down cargo
  • D. Maintain cargo temperature to reduce viscosity for efficient pumping
Answer: D — Maintain cargo temperature to reduce viscosity for efficient pumping
Steam/thermal heating coils keep heavy oils liquid above their pour point for easy pumping.

9. What is a Segregated Ballast Tank (SBT)?

  • A. Engine sump
  • B. Drinking water tank
  • C. Slop tank
  • D. Ballast tank completely separate from cargo oil system, filled only with clean sea water
Answer: D — Ballast tank completely separate from cargo oil system, filled only with clean sea water
SBT systems prevent seawater contamination by keeping ballast completely isolated from cargo.

10. What condition requires immediate stopping of oil cargo transfer?

  • A. Sunset
  • B. Cargo spill on deck, manifold valve leakage, sudden pressure drop, or lightning storm
  • C. Radio broadcast start
  • D. Change of steering helm
Answer: B — Cargo spill on deck, manifold valve leakage, sudden pressure drop, or lightning storm
Any containment failure or atmospheric hazard requires immediate operational shutdown.

11. What is the Lower Explosive Limit (LEL) of typical crude oil hydrocarbon vapors in air?

  • A. 20%
  • B. 50%
  • C. Approximately 1% by volume
  • D. 0.01%
Answer: C — Approximately 1% by volume
Crude oil vapors become flammable at ~1% LEL and reach Upper Explosive Limit at ~10%.

12. What is the role of an Oil Spill Removal Organization (OSRO)?

  • A. Provide containment booms, skimmers, and professional cleanup assistance
  • B. Inspect engine certificates
  • C. Operate cargo pumps
  • D. Issue bill of lading
Answer: A — Provide containment booms, skimmers, and professional cleanup assistance
OSRO contractors provide specialized spill response hardware and cleanup operations.

13. Why is water prohibited as an extinguishing agent directly on liquid oil pool fires?

  • A. Water turns oil to gas
  • B. Water is heavier than oil; oil floats on top and spreads burning liquid over wider area
  • C. Water freezes oil
  • D. Water generates oxygen
Answer: B — Water is heavier than oil; oil floats on top and spreads burning liquid over wider area
Water streams sink below burning oil, causing violent boiling and fire spread. Foam is used.

14. What fire extinguishing system is standard protection for oil tanker cargo deck areas?

  • A. CO2 gas flooding open deck
  • B. Sprinkler fresh water
  • C. Fixed Deck Foam System (Low expansion foam)
  • D. Halon gas
Answer: C — Fixed Deck Foam System (Low expansion foam)
Deck foam monitors smother liquid fuel surface fires by sealing off flammable vapors from air.

15. What is the purpose of ballast water exchange (BWE) under BWM Convention?

  • A. Cool deck
  • B. Replace coastal ballast water with open-ocean deep sea water to prevent invasive species transfer
  • C. Clean fuel tanks
  • D. Wash cargo lines
Answer: B — Replace coastal ballast water with open-ocean deep sea water to prevent invasive species transfer
Ballast exchange in deep sea (>200 nm, 200m depth) eliminates coastal invasive marine pests.

16. What device measures ullage, oil/water interface level, and temperature with a single portable probe?

  • A. MMC / UTI (Ullage-Temperature-Interface) portable tape
  • B. Wooden dipstick
  • C. Glass thermometer
  • D. Hydrometer
Answer: A — MMC / UTI (Ullage-Temperature-Interface) portable tape
UTI tapes attach to vapor locks, sounding liquid surface, oil-water interface, and temperature.

17. What is gas freeing on an oil tanker?

  • A. Heating cargo
  • B. Closing all vents
  • C. Filling tank with crude
  • D. Replacing hydrocarbon or inert gas in cargo tanks with fresh breathable air
Answer: D — Replacing hydrocarbon or inert gas in cargo tanks with fresh breathable air
Gas-freeing uses high-capacity blowers to introduce fresh air after purging hydrocarbons with inert gas.

18. What risk occurs if a cargo pump is run dry without liquid flow?

  • A. Paint peeling
  • B. Deck freezing
  • C. Electrical short circuit
  • D. Overheating of mechanical seals and bearings, causing fire hazard or pump seizure
Answer: D — Overheating of mechanical seals and bearings, causing fire hazard or pump seizure
Cargo pumps rely on liquid flow for cooling; dry running causes rapid frictional heating.

19. What publication specifies standard communication signals between ship and tugs during berthing?

  • A. Medical Guide
  • B. Standard Marine Communication Phrases (SMCP) / Port Berthing Plan
  • C. Cookery Guide
  • D. Engine Telegraph Manual
Answer: B — Standard Marine Communication Phrases (SMCP) / Port Berthing Plan
SMCP ensures standardized clear VHF communication between pilot, master, tugs, and mooring crew.

20. Who has ultimate responsibility for the safety of cargo operations and environmental compliance on an oil tanker?

  • A. Shore pump operator
  • B. Customs inspector
  • C. The Ship's Master
  • D. Port Agent
Answer: C — The Ship's Master
The Master retains overarching responsibility for overall safety, vessel seaworthiness, and MARPOL compliance.

21. What is the alternative means of supply of sea water to the deck seal unit in case of maintenance or failure of designated deck seal Pump?

  • A. Through the deck fire line
  • B. Through the main sea water pump or the cargo condenser pump
  • C. Through the deck seal pump fitted in the engine room
  • D. Through a sea water aggregate pump fixed on the cargo deck
Answer: B — Through the main sea water pump or the cargo condenser pump
If the designated deck seal pump fails or is undergoing maintenance, sea water supply to the inert gas deck seal can be alternatively lined up from the main sea water service line or cargo condenser cooling pump.

22. Expand the abbreviation 'ESD' system?

  • A. Emergency stop and disconnect system
  • B. Emergency shut down system
  • C. Emergency shore disconnection system
  • D. Emergency shutting and disconnecting system
Answer: B — Emergency shut down system
ESD stands for Emergency Shut Down system, which is designed to safely stop cargo transfer operations in the event of an emergency.

23. Chapter 4 MARPOL annex VI was adopted on?

  • A. 17th August 2009
  • B. 1st March 2012
  • C. 1St January 2010
  • D. 15th July 2011
Answer: D — 15th July 2011
Chapter 4 of MARPOL Annex VI (Regulations on energy efficiency for ships, including EEDI and SEEMP) was adopted on 15th July 2011 under Resolution MEPC.203(62).

24. A centrifugal bilge pump requires priming?

  • A. In order to overcome the potential energy of water in the discharge line.
  • B. Primarily to lubricate the shaft.
  • C. Due to the inability of this type of pump to lift water to cover the suction(eye)) of the empeller.
  • D. To initially unload the pump by having its head pressure equal to discharge pressure
Answer: C — Due to the inability of this type of pump to lift water to cover the suction(eye)) of the empeller.
Centrifugal pumps are not self-priming because they cannot create a sufficient vacuum with air/vapour to draw liquid into the impeller eye; hence, priming is required to fill the casing and suction.

25. A scrubber tower which is normally acts as a _____.

  • A. Heater
  • B. Cooler
  • C. Humidifier
  • D. Dehumidifier
Answer: B — Cooler
The scrubber tower cools the hot flue gas from the boiler by direct contact with seawater spray and removes sulphur dioxide (SO2) and soot particles.

26. On many modern VLCC tankers which of the following device is used to top up IG pressure on loaded condition in case of slight reduce in tank temperature.

  • A. Supplement IG by the boiler and standard method.
  • B. Do not fire the main boiler plant due to excess fuel consumption which is more than allowed in the agreement
  • C. A separate IGG plant if installed separately
  • D. Wat till the discharge port, open tank vent to allow a little rise in tank pressure.
Answer: A — Supplement IG by the boiler and standard method.
When tank temperature drops causing tank pressure to decrease during loaded passage, inert gas pressure is maintained by topping up from the boiler flue gas system using standard procedures.

27. What is handy size tanker.

  • A. Tankers of about 12000 to 25000 DWT.
  • B. From 26000 to 16500 tdw
  • C. Under 16,500 DWT
  • D. from 36000 to 26000 tdw
Answer: A — Tankers of about 12000 to 25000 DWT.
Handy size tankers generally refer to smaller product or chemical tankers typically in the range of 12,000 to 25,000 DWT.

28. Before cargo operations begin the responsible person on board and the terminal representative will complete___?

  • A. Meeting agreement
  • B. Ship / shore operation plan
  • C. Ship details plan
  • D. Ship / shore safety check list
Answer: D — Ship / shore safety check list
In accordance with ISGOTT guidelines, the Ship/Shore Safety Checklist (SSSCL) must be jointly verified and signed by the responsible ship officer and terminal representative prior to starting cargo operations.

29. In theory, a cargo pump should be able to draw up a liquid to a height equaling atmospheric pressure. This would be approximately ___?

  • A. 30 meters
  • B. 15 meters
  • C. 5 meters
  • D. 10 meters
Answer: D — 10 meters
Standard atmospheric pressure (101.3 kPa / 1.013 bar) corresponds to a theoretical water column height of approximately 10.33 meters.

30. In flue gas line. It would be advantageous to fit _______door downstream from the flue gas valve?

  • A. Inspection
  • B. Access
  • C. both a and b
  • D. None of the above
Answer: C — both a and b
Fitting inspection and access doors downstream of the flue gas isolating valve allows inspection, cleaning of soot deposits, and maintenance of the line and valve seal.

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