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OCTCO/OCTF exit exam questions and answers — Set 15 — Oil and Chemical Tanker Cargo Operations

Set 15 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 15 — 30 OCTCO/OCTF exit exam questions with answers

1. Which type of gas carrier, based on the hazardous nature of the cargo, can carry the largest quantity of cargo?

  • A. Type 1G
  • B. Type 2G
  • C. Type 2PG
  • D. Type 3G
Answer: D — Type 3G
Under the IGC Code, Type 3G ships carry the least hazardous gases and have the least stringent damage survival and tank location requirements, so they can carry the largest cargo quantities; Type 1G carries the most hazardous products.

2. What is a cofferdam?

  • A. A tube fitted to an ullage hole
  • B. A void or empty space separating two tanks
  • C. An opening in the deck used for cleaning tanks
  • D. The area the product is loaded into
Answer: B — A void or empty space separating two tanks
A cofferdam is an isolating void space between two bulkheads or decks, separating cargo tanks from machinery spaces, accommodation or other tanks, so that leakage from one compartment cannot pass directly into another.

3. What is segregated ballast?

  • A. Segregation of dirty and clean ballast
  • B. Individual tank ballast that has or has not yet been exchanged
  • C. A standard quantity of ballast maintained on repeated voyages in the same trade
  • D. Ballast carried in tanks completely separated from the cargo oil and fuel oil systems
Answer: D — Ballast carried in tanks completely separated from the cargo oil and fuel oil systems
MARPOL Annex I defines segregated ballast as ballast water introduced into a tank completely separated from the cargo oil and fuel oil systems and permanently allocated to ballast, so it never contacts oil.

4. The heat given to or given up by a substance in changing state is called

  • A. Conduction
  • B. Fusion
  • C. Latent heat
  • D. Solidification
Answer: C — Latent heat
Latent heat is absorbed or released during a change of state, such as melting or boiling, without any change in temperature. This is important in LPG and LNG carriage, where boil-off absorbs latent heat of vaporisation.

5. A centrifugal pump should always be started against a closed or partially open discharge valve in order to ____ the load.

  • A. Minimise
  • B. Maximise
  • C. Increase
  • D. Reverse
Answer: A — Minimise
With the discharge valve closed, flow and absorbed power of a centrifugal pump are at their lowest. Starting this way minimises motor starting load and prevents pressure surges, after which the valve is opened gradually.

6. An uncontrolled liquid or vapour release can occur through

  • A. Overfilling of tanks
  • B. Unforeseen opening of safety relief valves, bursting of a hose or fracture of cargo piping
  • C. Tank or pipe leakage
  • D. All of the above
Answer: D — All of the above
Overfilling, relief valve lifting, hose or pipe failure and tank or line leakage are all recognised causes of uncontrolled cargo release, and each must be covered in the ship's emergency and spill response procedures.

7. To what should an emergency plan be directed?

  • A. The rescue and treatment of casualties and safeguarding others
  • B. Minimising damage to ship, property and the environment
  • C. Containing and bringing the incident under control
  • D. All of the above
Answer: D — All of the above
ISGOTT states that emergency plans should aim at rescuing and treating casualties, safeguarding others, minimising damage to property and the environment, and bringing the incident under control.

8. The purpose of pressure/vacuum valves is to

  • A. Measure pressure or suction levels in cargo tanks
  • B. Enable loading or discharge of oil without opening sighting ports
  • C. Provide for the flow of small volumes of tank atmosphere caused by thermal variations
  • D. Provide an audible alarm in the event of pressure build-up
Answer: C — Provide for the flow of small volumes of tank atmosphere caused by thermal variations
P/V valves allow small volumes of vapour to flow out or air/IG in when tank pressure changes due to thermal variations, keeping pressure within design limits. Large volumes during cargo handling go through the venting system or mast riser.

9. That part of a gas carrier which contains the cargo containment system, cargo pump and compressor rooms, including deck areas over them, is known as the

  • A. Cargo containment
  • B. Cargo area
  • C. Motor room
  • D. None of the above
Answer: B — Cargo area
The IGC Code defines the cargo area as that part of the ship containing the cargo containment system and cargo pump and compressor rooms, together with deck areas over the full length and breadth of that part.

10. An enclosed space in the cargo area external to the cargo containment system, other than a hold space, ballast space, cargo pump or compressor room or any space in normal use by personnel, is called a

  • A. Accommodation space
  • B. Gas-free area
  • C. Void space
  • D. None of the above
Answer: C — Void space
The IGC Code defines a void space as an enclosed space in the cargo area external to a cargo containment system, other than hold, ballast, fuel oil, cargo pump or compressor rooms or any space in normal use by personnel.

11. What kind of extinguishing medium should you choose to put out an electrical fire?

  • A. Water
  • B. Dry powder
  • C. Foam
  • D. A jet of sea water
Answer: B — Dry powder
Dry powder (and CO2) are non-conducting, so they can be used safely on live electrical equipment. Water and foam conduct electricity and risk electric shock to the fire fighter.

12. Which hand gloves are best suited for handling solvents, petrol, oils and many chemicals?

  • A. PVC gloves
  • B. Natural rubber gloves
  • C. Neoprene or nitrile rubber gloves
  • D. Cotton gloves
Answer: C — Neoprene or nitrile rubber gloves
Neoprene and nitrile rubber resist oils, petroleum products, solvents and many chemicals far better than natural rubber or PVC. Cotton gloves absorb liquids and give no chemical protection.

13. The stretcher for emergency rescue from the pump room should be

  • A. Available close to the pump room
  • B. Kept permanently rigged for hoisting an injured person
  • C. Kept in the ship's hospital and clearly marked
  • D. Kept in the deck store
Answer: B — Kept permanently rigged for hoisting an injured person
ISGOTT recommends that pump room rescue equipment, including a stretcher suitable for vertical lifting, be kept rigged and ready for immediate use so a casualty can be hoisted out without delay.

14. Procedures for the ship's standard emergencies are documented in the

  • A. P&A Manual
  • B. IG and COW manuals
  • C. ISM (SMS) procedures
  • D. Cargo Record Book
Answer: C — ISM (SMS) procedures
ISM Code Section 8 requires the company to identify potential shipboard emergencies and establish procedures to respond to them, so these are documented in the Safety Management System.

15. The major danger from a vapour cloud occurs if it is

  • A. Dissipated in the atmosphere
  • B. Reduced in vapour concentration
  • C. Ignited
  • D. Monitored continuously
Answer: C — Ignited
A flammable vapour cloud that finds an ignition source can cause a flash fire or vapour cloud explosion over a wide area. Dispersion below the LEL removes the fire hazard, which is why ignition sources are controlled during a release.

16. Systemic poisons are those that cause an adverse health effect

  • A. In organs or systems of the body away from the point of contact
  • B. Only on the skin at the point of contact
  • C. Only to the eyes
  • D. Only in the respiratory tract at the point of entry
Answer: A — In organs or systems of the body away from the point of contact
Systemic poisons are absorbed into the bloodstream and act on internal organs or body systems, such as the liver, kidneys or nervous system, rather than only at the point of contact as local irritants do.

17. When an inhibited chemical cargo is loaded, the shipper should provide

  • A. A sample of the inhibitor to the chief officer
  • B. An MSDS for the added inhibitor only
  • C. An inhibitor certificate valid for the voyage
  • D. A Certificate of Fitness
Answer: C — An inhibitor certificate valid for the voyage
The IBC Code requires an inhibitor certificate for cargoes that need inhibition, giving the inhibitor name and amount, date added, expected lifetime, temperature limits and actions if the voyage exceeds the inhibitor's effective life.

18. In chemical tankers with common pipelines, cargo segregation is achieved by

  • A. Isolating tanks after completion of loading
  • B. Closing all tank valves after completion of loading
  • C. Inserting blind flanges in the pipes concerned
  • D. Lashing the valve handwheels
Answer: C — Inserting blind flanges in the pipes concerned
Closed valves alone are a single barrier and may leak. Positive segregation between incompatible grades in common lines requires removal of spool pieces or insertion of blind flanges in the lines concerned.

19. The Draeger tube system is used for

  • A. Ammonia gas detection only
  • B. Nitrogen gas detection only
  • C. Multi-gas detection
  • D. Hydrocarbon LEL measurement only
Answer: C — Multi-gas detection
Draeger (chemical indicator) tubes are made for many specific gases, such as H2S, benzene, ammonia and CO. Fitting the appropriate tube to the pump allows detection of a wide range of toxic gases with one system.

20. Cargo tanks can be

  • A. Independent or integral
  • B. Only independent
  • C. Only integral
  • D. Only portable
Answer: A — Independent or integral
Cargo tanks may be integral, forming part of the hull structure, or independent, self-supporting and not part of the hull, as described in the IBC and IGC Codes.

21. A resuscitator is used to assist or restore

  • A. Breathing
  • B. Pulse rate
  • C. Both breathing and pulse rate
  • D. Blood pressure
Answer: A — Breathing
A resuscitator delivers air or oxygen to the lungs of a casualty who has stopped breathing or is breathing inadequately. It does not restore circulation, which requires chest compressions or a defibrillator.

22. A Framo centrifugal cargo pump is driven by

  • A. An electric motor in the tank
  • B. A hydraulic motor using hydraulic oil
  • C. A steam turbine
  • D. Compressed air
Answer: B — A hydraulic motor using hydraulic oil
Framo submerged cargo pumps are driven by a hydraulic motor at the pump, supplied with high-pressure hydraulic oil from a central power pack, so no electrical equipment is placed in the cargo tank.

23. Products listed in Chapter 17 of the IBC Code are carried on which type of tanker?

  • A. Chemical tanker
  • B. Oil tanker
  • C. Both oil and chemical tankers
  • D. Gas carrier
Answer: A — Chemical tanker
IBC Code Chapter 17 is the summary of minimum requirements for dangerous chemicals carried in bulk, giving ship type and other requirements. These cargoes must be carried on chemical tankers certified under the IBC Code.

24. The Cargo Record Book is mandatory on which tankers?

  • A. Oil tankers
  • B. Chemical tankers (NLS)
  • C. Both oil and chemical tankers
  • D. Gas carriers
Answer: B — Chemical tankers (NLS)
MARPOL Annex II Regulation 15 requires every ship carrying noxious liquid substances in bulk to have a Cargo Record Book. Oil tankers instead keep the Oil Record Book Part II under Annex I.

25. What quantity of hydrogen sulphide is harmful to health?

  • A. Only large quantities
  • B. Even a small quantity
  • C. Only medium quantities
  • D. No quantity; it is harmless
Answer: B — Even a small quantity
Hydrogen sulphide is highly toxic even at low concentrations; the occupational limit is only a few ppm, and higher concentrations paralyse the sense of smell, so odour cannot be relied on to detect it.

26. Draeger tubes are used for measuring which type of gas?

  • A. Oxygen
  • B. Toxic gases
  • C. Hydrogen
  • D. Nitrogen
Answer: B — Toxic gases
Chemical indicator (Draeger) tubes are used to measure low concentrations of toxic gases, such as H2S, benzene or CO, in ppm. Oxygen and hydrocarbon LEL are measured with separate electronic instruments.

27. Petroleum having a flash point below 60°C is known as

  • A. Pure
  • B. Volatile
  • C. Safe
  • D. Non-volatile
Answer: B — Volatile
ISGOTT classifies petroleum with a flash point below 60°C (closed cup) as volatile, since it can give off flammable gas at normal temperatures. Petroleum with a flash point of 60°C or above is non-volatile.

28. Can cold work create a source of ignition?

  • A. No, cold work by definition cannot create a source of ignition
  • B. Yes, it always creates a source of ignition
  • C. Yes, but only in the pump room
  • D. Only when carried out at night
Answer: A — No, cold work by definition cannot create a source of ignition
ISGOTT defines cold work as work that cannot create a source of ignition. Any work that could generate sparks or heat sufficient to ignite flammable vapour is treated as hot work and needs a hot work permit.

29. Odour threshold is measured in

  • A. ppt (parts per thousand)
  • B. ppm (parts per million)
  • C. % LEL
  • D. % by volume
Answer: B — ppm (parts per million)
The odour threshold is the lowest concentration of a vapour in air that can be detected by smell. Such concentrations are very small and are expressed in parts per million (ppm) by volume.

30. A gravity tank can be ____.

  • A. Integral only
  • B. Independent only
  • C. Either integral or independent
  • D. Membrane type only
Answer: C — Either integral or independent
Under the IBC Code a gravity tank is one with a design pressure not exceeding 0.7 bar gauge at the top of the tank. Gravity tanks may be either integral with the hull structure or independent tanks.

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