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OCTCO/OCTF exit exam questions and answers — Set 17 — Oil and Chemical Tanker Cargo Operations

Set 17 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 17 — 30 OCTCO/OCTF exit exam questions with answers

1. Heating of crude oil cargo is required

  • A. Only for some crude oils, such as waxy or high pour point crudes
  • B. For all crude oils
  • C. Never, for any crude oil
  • D. Only for light crude oils
Answer: A — Only for some crude oils, such as waxy or high pour point crudes
Only waxy, high viscosity or high pour point crudes need heating to keep them pumpable and avoid wax deposition. Most light crudes are carried without heating.

2. On a tanker fitted with an inert gas system, the pressure/vacuum breaker is normally fitted

  • A. On the inert gas main, serving the cargo tanks collectively
  • B. On every individual cargo tank
  • C. On the ballast tanks
  • D. On the fresh water tanks
Answer: A — On the inert gas main, serving the cargo tanks collectively
A P/V breaker, usually liquid filled, is fitted on the inert gas main to protect the cargo tanks against excessive pressure or vacuum if the P/V valves fail. It is not required on every individual tank.

3. A dedicated chemical tanker

  • A. Transports the same cargo on each voyage
  • B. Carries different cargo grades on every voyage
  • C. Carries only dry bulk cargo
  • D. Carries only oil
Answer: A — Transports the same cargo on each voyage
A dedicated tanker is employed in a trade carrying the same product on every voyage, so tank cleaning between cargoes is minimal and contamination risk is low.

4. Adiabatic expansion means

  • A. Expansion without heat transfer to or from the surroundings
  • B. Expansion with continuous heating
  • C. Expansion at constant temperature
  • D. Expansion at constant volume
Answer: A — Expansion without heat transfer to or from the surroundings
In an adiabatic process no heat enters or leaves the system. During adiabatic expansion the gas does work at the expense of its internal energy, so its temperature falls.

5. An exothermic reaction is one that

  • A. Gives out heat
  • B. Absorbs heat
  • C. Neither gives out nor absorbs heat
  • D. Occurs only at low temperature
Answer: A — Gives out heat
An exothermic reaction releases heat to its surroundings. Uncontrolled exothermic reactions such as polymerisation are a major hazard with some chemical cargoes.

6. An inhibitor added to a cargo such as styrene acts as

  • A. A negative catalyst that slows or prevents self-reaction
  • B. A positive catalyst that speeds up reaction
  • C. An inert gas
  • D. A colouring agent
Answer: A — A negative catalyst that slows or prevents self-reaction
An inhibitor slows down or prevents self-reaction such as polymerisation. The IBC Code requires an inhibitor certificate stating its name, amount and effective life for such cargoes.

7. Ullage is the distance between the liquid level and the

  • A. Tank bottom
  • B. Reference point at the tank top
  • C. Ship's keel
  • D. Waterline
Answer: B — Reference point at the tank top
Ullage is measured from the reference point at the top of the tank down to the liquid surface. Sounding is the corresponding distance measured from the tank bottom up to the liquid surface.

8. During a fire drill on board, crew members should

  • A. Act as if the fire is real
  • B. Treat it casually as a routine exercise
  • C. Only observe from the accommodation
  • D. Remain in their cabins
Answer: A — Act as if the fire is real
Drills are meant to be realistic so that crew respond correctly in a real emergency. SOLAS III/19 requires drills to be conducted, as far as practicable, as if there were an actual emergency.

9. The deck water seal of the inert gas system

  • A. Prevents the backflow of hydrocarbon gases into non-hazardous areas
  • B. Relieves sudden large overpressures in the system
  • C. Acts as an emergency shutdown when inlet pressure exceeds the safe working pressure
  • D. Cools the inert gas and prevents soot from entering the cargo tanks
Answer: A — Prevents the backflow of hydrocarbon gases into non-hazardous areas
The FSS Code requires the deck water seal as the principal non-return barrier, preventing hydrocarbon gas from flowing back from the cargo tanks to the machinery spaces when the inert gas plant is stopped.

10. Which organization is responsible for establishing regulations for the transportation of dangerous goods by sea?

  • A. International Maritime Organization (IMO)
  • B. International Tanker Owners Pollution Federation (ITOPF)
  • C. International Association of Classification Societies (IACS)
  • D. International Chamber of Shipping (ICS)
Answer: A — International Maritime Organization (IMO)
IMO, the UN agency for shipping, regulates the carriage of dangerous goods by sea through SOLAS Chapter VII, MARPOL and Codes such as the IMDG, IBC and IGC Codes.

11. What is the purpose of a Material Safety Data Sheet (MSDS)?

  • A. Provide information on the stability and structural integrity of the vessel
  • B. Determine the compatibility of different chemicals during cargo operations
  • C. Document the vessel's cargo operations for regulatory compliance
  • D. Provide information on the properties and hazards of chemicals
Answer: D — Provide information on the properties and hazards of chemicals
The MSDS or SDS gives the physical and chemical properties, health and fire hazards, PPE, first aid, spill and firefighting measures for a product. SOLAS VI/5-1 requires it for MARPOL Annex I cargoes.

12. What is the purpose of a Shipboard Oil Pollution Emergency Plan (SOPEP)?

  • A. Ensure the safety and security of ships and port facilities
  • B. Verify the vessel's compliance with ballast water management regulations
  • C. Document the procedures for responding to oil pollution incidents
  • D. Provide guidelines for the safe loading and unloading of cargo
Answer: C — Document the procedures for responding to oil pollution incidents
MARPOL Annex I Regulation 37 requires a SOPEP containing reporting requirements, contact lists and the actions to be taken by the crew to control and reduce an oil discharge after an incident.

13. What is the purpose of a cargo compatibility chart?

  • A. Determine the vessel's stability during cargo operations
  • B. Prevent the vessel from carrying too many grades
  • C. Provide guidelines for the safe stowage of deck cargo
  • D. Verify the compatibility of different chemicals during cargo operations
Answer: D — Verify the compatibility of different chemicals during cargo operations
A compatibility chart, such as the USCG chart, shows which chemical groups may react dangerously with each other, so that incompatible cargoes are not stowed in adjacent tanks or handled through common lines.

14. Which equipment is commonly used to measure the temperature of a cargo in a tank?

  • A. Thermometer
  • B. Hydrometer
  • C. Flowmeter
  • D. Pressure gauge
Answer: A — Thermometer
Cargo temperature is measured with a thermometer or temperature sensor, often built into the UTI tape or fixed gauging system, and is needed to correct cargo volume to standard temperature.

15. What is the primary purpose of an inert gas system (IGS) on an oil or chemical tanker?

  • A. Prevent cargo contamination during loading and unloading
  • B. Control the cargo temperature within acceptable limits
  • C. Monitor the pressure and temperature of the cargo tanks
  • D. Maintain an inert atmosphere in the cargo tanks to prevent explosions
Answer: D — Maintain an inert atmosphere in the cargo tanks to prevent explosions
The IGS keeps the oxygen content of cargo tank atmospheres at 8% or less, below the level that supports combustion, so that a flammable mixture cannot form and fire or explosion is prevented (SOLAS II-2/4.5.5).

16. What is the purpose of a cargo pump on an oil or chemical tanker?

  • A. Measure the flow rate of the cargo during loading and unloading
  • B. Provide a connection point for cargo sampling and analysis
  • C. Monitor the pressure and temperature of the cargo tanks
  • D. Transfer cargo between the ship's cargo tanks and shore tanks
Answer: D — Transfer cargo between the ship's cargo tanks and shore tanks
Cargo pumps, such as centrifugal or deepwell pumps, move cargo out of the ship's tanks to shore storage or another ship during discharge, and are also used for internal transfers.

17. What is the purpose of a cargo tank cleaning procedure on an oil or chemical tanker?

  • A. Remove residues of previous cargoes to prevent contamination
  • B. Verify the cargo's compliance with environmental regulations
  • C. Control the cargo temperature within acceptable limits
  • D. Monitor the pressure and temperature of the cargo tanks
Answer: A — Remove residues of previous cargoes to prevent contamination
Tank cleaning removes residues of the previous cargo so that the next cargo is not contaminated, and to allow gas freeing for entry or repairs. Cleaning must follow the P&A Manual and MARPOL requirements.

18. Which equipment is commonly used to monitor the pressure of cargo in a tank?

  • A. Pressure gauge
  • B. Radar tank gauge
  • C. Dip tape
  • D. Hydrometer
Answer: A — Pressure gauge
Tank vapour space pressure is monitored by pressure gauges or transmitters, with readings displayed in the cargo control room and high and low pressure alarms fitted as required by SOLAS and the IBC Code.

19. Which organization is responsible for establishing standards for the training and certification of seafarers?

  • A. International Association of Classification Societies (IACS)
  • B. International Maritime Organization (IMO)
  • C. International Chamber of Shipping (ICS)
  • D. International Tanker Owners Pollution Federation (ITOPF)
Answer: B — International Maritime Organization (IMO)
IMO adopted the STCW Convention and Code, which set mandatory minimum standards of training, certification and watchkeeping, including tanker cargo training under Regulation V/1-1.

20. What is the purpose of a cargo measurement procedure on an oil or chemical tanker?

  • A. Determine the compatibility of different chemicals during cargo operations
  • B. Measure the flow rate and quantity of the cargo during loading and unloading
  • C. Control the cargo temperature within acceptable limits
  • D. Provide guidelines for the safe stowage of cargo
Answer: B — Measure the flow rate and quantity of the cargo during loading and unloading
Cargo measurement, by ullaging, temperature and density readings, determines the quantity loaded or discharged and the rates achieved, which is needed for cargo documents and to avoid overfill.

21. Which equipment is commonly used to measure the density of a cargo?

  • A. Hydrometer
  • B. Gas detector
  • C. Oxygen analyzer
  • D. Inert gas generator
Answer: A — Hydrometer
A hydrometer measures the density or specific gravity of a liquid sample. Density is needed to convert measured cargo volume into weight for cargo calculations and documents.

22. What is the primary purpose of a cargo tank coating on an oil or chemical tanker?

  • A. Control the cargo temperature within acceptable limits
  • B. Increase the cargo pumping rate
  • C. Provide structural strength to the cargo tanks
  • D. Protect the tank structure from corrosion and chemical attack
Answer: D — Protect the tank structure from corrosion and chemical attack
Tank coatings such as epoxy or zinc silicate form a barrier between the steel and the cargo or ballast, protecting the structure from corrosion and chemical attack and also making cleaning easier.

23. What is the purpose of a cargo tank pressure/vacuum valve on an oil or chemical tanker?

  • A. Monitor the pressure and temperature of the cargo tanks
  • B. Maintain the structural integrity of the cargo tanks
  • C. Control the flow rate of the cargo during loading and unloading
  • D. Prevent excessive pressure or vacuum in the cargo tanks
Answer: D — Prevent excessive pressure or vacuum in the cargo tanks
P/V valves allow small volumes of vapour or air to pass during thermal breathing and cargo operations, preventing tank overpressure or vacuum that could damage the structure (SOLAS II-2/4.5.3).

24. What is the purpose of a cargo heating coil on an oil or chemical tanker?

  • A. Prevent cargo contamination during loading and unloading
  • B. Control the cargo temperature within acceptable limits
  • C. Monitor the pressure and temperature of the cargo tanks
  • D. Provide structural strength to the cargo tanks
Answer: B — Control the cargo temperature within acceptable limits
Heating coils carry steam or thermal oil through the tank to keep viscous or high pour point cargoes at the temperature specified by the shipper, so they remain pumpable without overheating.

25. Which equipment is commonly used to measure the flow rate of a cargo during loading and unloading?

  • A. Flowmeter
  • B. Thermometer
  • C. Pressure gauge
  • D. Radar tank gauge
Answer: A — Flowmeter
A flowmeter measures the rate of liquid flow in a pipeline. Rates are also cross-checked by ullage changes over time to monitor loading and discharging.

26. What is the primary purpose of a cargo tank washing machine on a chemical tanker?

  • A. Control the cargo temperature within acceptable limits
  • B. Remove residual cargo from the tanks
  • C. Monitor the pressure and temperature of the cargo tanks
  • D. Provide structural strength to the cargo tanks
Answer: B — Remove residual cargo from the tanks
Fixed or portable tank washing machines direct high-pressure jets of water or cleaning medium over tank surfaces to remove residual cargo, as required by the P&A Manual and before loading a different grade.

27. What is the purpose of a cargo tank level alarm on an oil or chemical tanker?

  • A. Measure the flow rate and quantity of the cargo during loading and unloading
  • B. Provide a connection point for cargo sampling and analysis
  • C. Monitor the pressure and temperature of the cargo tanks
  • D. Warn against overfilling or low levels in the cargo tanks
Answer: D — Warn against overfilling or low levels in the cargo tanks
High level and overfill alarms, required by the IBC Code and SOLAS for many tankers, warn the crew in time to stop loading or close valves, preventing overflow and pollution.

28. Which document provides information on the procedures for the safe handling and transport of dangerous goods in packaged form?

  • A. International Load Line Certificate (ILLC)
  • B. International Maritime Dangerous Goods (IMDG) Code
  • C. Safety Data Sheet (SDS)
  • D. Shipper's Declaration for Dangerous Goods (SDDG)
Answer: B — International Maritime Dangerous Goods (IMDG) Code
The IMDG Code, mandatory under SOLAS Chapter VII Part A, covers classification, packing, marking, labelling, documentation and stowage of dangerous goods carried in packaged form.

29. Which fire-extinguishing medium is commonly used for cargo deck fires on chemical tankers?

  • A. CO2 (carbon dioxide)
  • B. Foam
  • C. Water mist
  • D. Dry chemical powder
Answer: B — Foam
The IBC Code (Chapter 11) requires a fixed deck foam system for cargo area protection on chemical tankers, using foam, often alcohol resistant, suitable for the products carried.

30. What is the purpose of a vapour control system on an oil tanker?

  • A. Prevent cargo leakage during loading and unloading
  • B. Minimize the emission of volatile organic compounds (VOCs)
  • C. Maintain the cargo temperature within acceptable limits
  • D. Monitor cargo levels in the tanks
Answer: B — Minimize the emission of volatile organic compounds (VOCs)
A vapour emission control system collects displaced cargo vapour during loading and returns it ashore, limiting VOC release to the atmosphere as required under MARPOL Annex VI Regulation 15 at regulated terminals.

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