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OCTCO/OCTF exit exam questions and answers — Set 8

Set 8 of the Oil and Chemical Tanker Cargo Operations (OCTCO/OCTF) exit exam bank — 30 of 252 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 8 — 30 OCTCO/OCTF exit exam questions with answers

1. The groups of alcohols and carbohydrates includes products which may be produced by fermentation, such as?

  • A. Liquor
  • B. Wine
  • C. Mollasses
  • D. None of these
Answer: B — Wine
Fermentation of organic sugars and starches produces alcohols (ethanol) and fermented beverages such as wine and spirits.

2. To discharge the last amount of cargo ashore, the stripping pump through the small diameter line is used from cargo tanks. Where does this small diameter line come from in the pump room ?

  • A. From the individual stripping line to the stripping pump.
  • B. From the tank suction line to the Main cargo oil pump.
  • C. From the cargo pump suction pipe line to the stripping pump.
  • D. From the cargo pump discharge line to the stripping pump.
Answer: D — From the cargo pump discharge line to the stripping pump.
The small-diameter MARPOL stripping line on an oil tanker connects the cargo pump discharge manifold to the shore connection to discharge the final liquid residue from cargo lines.

3. The term solubility refers to the ability to mix with _________?

  • A. Oil
  • B. Air
  • C. Water
  • D. other liquids
Answer: D — other liquids
Solubility is the chemical property describing the ability of a substance to dissolve and form a homogeneous mixture with another liquid or solvent.

4. Fixed foam monitors having a maximum capacity of _____ L/min?

  • A. 4400
  • B. 5500
  • C. 6600
  • D. 7700
Answer: D — 7700
Large fixed deck foam monitors installed on supertankers can have a maximum discharge capacity of up to 7,700 litres per minute for rapid deck fire suppression.

5. Cargo tanks are not ____ with IG before gas freeing then the concentration of atmosphere will pass through flammable range?

  • A. Crude oil washed
  • B. Purged
  • C. Tank cleaning
  • D. Re-inerting
Answer: B — Purged
Before gas freeing cargo tanks with fresh air, tanks containing hydrocarbon vapours must first be purged with inert gas until the hydrocarbon level is below the critical dilution line.

6. In scrubber _____ is readily absorbed by water?

  • A. SO2
  • B. SO3
  • C. SO4
  • D. Sox
Answer: A — SO2
In the inert gas scrubber tower, sulfur dioxide (SO2) in the flue gas is readily dissolved and absorbed by the alkaline seawater spray.

7. Inert gas system has scrubber tower in a flue gas from boiler flue gas type of system. What is the arrangement for a separately fired inert gas Generator?

  • A. The IG Generator also has scrubber tower combined with the furnace.
  • B. The IG Generator can also have a separate scrubber tower.
  • C. The separately fired IG Generator does not have a scrubber tower.
  • D. Conditions (A) and (C) are suitable.
Answer: A — The IG Generator also has scrubber tower combined with the furnace.
In separately fired inert gas generators (IGGs), the combustion chamber/furnace and the cooling/washing scrubber tower are integrated into a compact combined vertical unit.

8. Why CO2 is not used as an inert gas?

  • A. More denser
  • B. Have more conductivity
  • C. Have intense electro-static field
  • D. None of the above
Answer: C — Have intense electro-static field
Pure CO2 is not used for bulk tanker inerting because rapid expansion from high pressure generates intense electrostatic charges and sparks in flammable atmospheres.

9. Submerged cargo pumps cofferdam leakage is tested by the following intervals?

  • A. Every 6 months
  • B. Every 12 months
  • C. Every month
  • D. Every monthly & suitably after every operation of discharge/ballasting.
Answer: D — Every monthly & suitably after every operation of discharge/ballasting.
Submerged hydraulically driven cargo pump cofferdams must be purged and tested for seal leakage monthly and routinely after every cargo discharge or ballasting operation.

10. Who should tank cleaning operations be supervised by?

  • A. Shore representative
  • B. Pump man
  • C. Deck Officer
  • D. Responsible Officer
Answer: D — Responsible Officer
Tank cleaning and gas freeing operations must always be directly supervised by a qualified and designated Responsible Officer (Chief Officer).

11. With reference to liquefied gas operation, what is the term “rollover” used to describe?

  • A. When two or more stratified layers of different density LNG in the same tank suddenly mix together causing
  • B. Vapor pockets forming at the bottom of a half-filled tank
  • C. Custody transfer at the terminal
  • D. Moving LNG from one tank to another
Answer: A — When two or more stratified layers of different density LNG in the same tank suddenly mix together causing
Rollover in liquefied gas tankers refers to the sudden spontaneous mixing of stratified LNG layers of different densities, resulting in rapid boil-off vapour release.

12. What does code R stand in ship shore safety checklist?

  • A. Remarks
  • B. Request
  • C. Require
  • D. Re-checked
Answer: D — Re-checked
In the Ship/Shore Safety Checklist (SSSCL), the code 'R' indicates items that require periodic re-checking and logging at agreed time intervals throughout cargo operations.

13. Black oils are generally?

  • A. Static accumulators
  • B. Static non- accumulators
  • C. Both
  • D. None of the above
Answer: B — Static non- accumulators
Black oils (such as crude oils and heavy fuel oils) contain natural antistatic impurities and asphaltic components, making them static non-accumulators.

14. The gas regulating valve should be opened very slowly in order to avoid:

  • A. Back flow gas
  • B. Water carries over
  • C. Noise
  • D. Vibrations
Answer: A — Back flow gas
The inert gas regulating valve must be opened very slowly to prevent sudden pressure surges, backflow of gas, or water carry-over from the deck seal.

15. In crude oil tankers, the gas detectors installed should be?

  • A. Correct electrical classification
  • B. Weather proof
  • C. Corrosion resistant
  • D. All of the above
Answer: D — All of the above
Gas detection sensors and sampling units installed on crude oil tankers must have certified explosion-proof electrical ratings, weatherproof enclosures, and corrosion-resistant materials.

16. If the flash point of an oil cargo is 58°C, it is said to be?

  • A. Volatile
  • B. Non-volatile
  • C. Toxic
  • D. None of the above
Answer: A — Volatile
According to ISGOTT, petroleum having a closed-cup flashpoint below 60°C (such as 58°C) is classified as volatile petroleum.

17. Which is the basic safety device fitted on the deck inert gas line to monitor the supply condition of the inerted tanks and pipelines of supply of gas?

  • A. The inert gas low pressure alarm
  • B. The inert gas high temperature alarm
  • C. The inert gas low flow alarm
  • D. All the above (A), (B) and (C)
Answer: D — All the above (A), (B) and (C)
Basic safety monitoring devices fitted on the deck inert gas line include low-pressure alarms, high-temperature alarms, and low-flow alarms to safeguard tank integrity.

18. Which of these is a positive displacement pump?

  • A. Gear
  • B. Reciprocating
  • C. None of the above
  • D. Both (A) and (B)
Answer: D — Both (A) and (B)
Both gear pumps and reciprocating piston pumps operate by trapping fixed volumes of fluid and displacing it mechanically, making them positive displacement pumps.

19. What is the purpose of a “part flow system” installed on some oil tankers?

  • A. The Part Flow system makes it possible to discharge dirty ballast below the water line on older tankers.
  • B. The Part Flow system makes it possible to observe the discharge visually for oil content, on older tankers with discharge below the waterline.
  • C. The Part Flow system makes it possible to observe the discharge visually for oil content, even in darkness.
  • D. The Part Flow system makes it possible to measure the oil content, even if the Oil Discharge Monitoring Equipment is not working.
Answer: B — The Part Flow system makes it possible to observe the discharge visually for oil content, on older tankers with discharge below the waterline.
A part-flow system allows visual inspection of effluent discharged through below-waterline overboard lines on older tankers to detect any oil contamination.

20. Who should attend during connection of cargo oil transfer arms/hoses?

  • A. Pump man
  • B. Responsible deck officer
  • C. Able Seaman
  • D. Bosun
Answer: B — Responsible deck officer
Connecting and disconnecting cargo transfer arms, hoses, and manifolds must be directly supervised by a qualified, responsible deck officer.

21. During cargo operations, a wind blowing may ____?

  • A. Lower the temperature of the oil cargo
  • B. Form eddies containing petroleum vapor
  • C. Increase air pressure in a cargo tank
  • D. Decrease air pressure in a cargo tank
Answer: B — Form eddies containing petroleum vapor
During cargo loading, ambient wind blowing across the deck structure can create turbulent aerodynamic eddies that trap and concentrate flammable petroleum vapours.

22. In oil tankers, there are __ foam boxes on the cargo deck?

  • A. Two
  • B. Three
  • C. Four
  • D. Five
Answer: A — Two
On oil tankers, two dedicated foam boxes (hose/nozzle stations) are positioned on the cargo deck for rapid local foam application.

23. In IG system, ideally the blower casing should be ____ split with split bearings?

  • A. Horizontally
  • B. Vertically
  • C. Angularly
  • D. None of the above
Answer: B — Vertically
To allow easy maintenance, inspection, and impeller overhaul without dismantling ductwork, inert gas blower casings are ideally vertically split.

24. Before arriving in a port where it is intended to crude oil wash the tank washing system should be pressure tested to ____?

  • A. 150% of the working pressure
  • B. 125% of the normal working pressure
  • C. 75% of the normal working pressure
  • D. The normal working pressure
Answer: D — The normal working pressure
Before arriving in port for crude oil washing (COW), the entire tank washing piping system must be pressure tested to its normal working pressure to verify tightness.

25. LOT is defined as both a procedure and a practice?

  • A. Load on Top
  • B. Load on tanks
  • C. Load on Transverse
  • D. Load on Table
Answer: A — Load on Top
LOT stands for Load on Top, an operational oil retention procedure where new cargo is loaded directly on top of settled, decanted slop residues in compliance with MARPOL.

26. The minimum oxygen required for combustion?

  • A. 5%
  • B. 16%
  • C. 8%
  • D. 21%
Answer: B — 16%
Combustion of typical hydrocarbon vapours cannot be sustained when the oxygen concentration in the mixture falls below approximately 11% by volume (16% being the minimum required for open free-burning flames in air).

27. What are consequences of a ballast tank vent not working during deballasting operation?

  • A. The tank de pressurization and denting of side plates.
  • B. The tanks taking in cargo vapors during loading operation.
  • C. The cargo tank alteration of ullage are taking place.
  • D. Combination of all three a,b,c
Answer: A — The tank de pressurization and denting of side plates.
If a ballast tank air vent / vacuum valve fails during high-rate deballasting, internal vacuum can cause tank depressurization and severe structural buckling or denting of side shell plates.

28. Type 1 ship is a chemical tanker intended to transport chapter 17 of the IBC code product with very severe environmental and safety hazards which require maximum preventive measure to preclude an escape of such cargo.

  • A. False
  • B. True
  • C. High concentration of acid and organic compounds
  • D. Both(b)and(c)
Answer: D — Both(b)and(c)
Under the IBC Code, a Type 1 chemical tanker is designed to transport products presenting the most severe environmental and safety hazards, requiring maximum preventive containment measures.

29. A vessel is fitted with a sample locker or spill containment locker in the amidships, what is the general arrangement for firefighting of that compartment.

  • A. Foam applicator equipment.
  • B. Sprinkler system from the fire main
  • C. Portable extinguishers situated outside the compartment.
  • D. Any one of (A)or (C) in addition to (B)
Answer: D — Any one of (A)or (C) in addition to (B)
Fire protection for deck sample lockers and spill containment stores typically includes water sprinkler systems from the fire main or portable fire extinguishers situated adjacent to the compartment.

30. The inert gas leaving the demister is saturated with?

  • A. 90%RH
  • B. 80%RH
  • C. 100%RH
  • D. 60%RH
Answer: D — 60%RH
Inert gas leaving the scrubber demister is fully saturated with water vapour at 100% relative humidity before entering the deck distribution pipeline.

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