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OCTCO/OCTF exit exam questions and answers — Set 6

Set 6 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 6 — 30 OCTCO/OCTF exit exam questions with answers

1. The total capacity of all slop tanks on an oil tanker normally should be?

  • A. 1% of the total oil carrying capacity of ship
  • B. 2% of the total oil carrying capacity of ship
  • C. 3% of the total oil carrying capacity of ship
  • D. 4% of the total oil carrying capacity of ship
Answer: C — 3% of the total oil carrying capacity of ship
Under MARPOL Annex I, the total capacity of slop tanks on an oil tanker must normally not be less than 3% of the vessel's total oil cargo carrying capacity (or 2% for SBT tankers).

2. In chemical tankers the coding system used by the IBC Code for an independent tank is?

  • A. 1
  • B. 2
  • C. G
  • D. P
Answer: A — 1
Under the IBC Code tank type classification, an independent tank (not forming part of the ship's hull structure) is designated by the code 1.

3. Which of the following is cofferdam?

  • A. Chain locker
  • B. Pump room on an oil tanker
  • C. Deep tank
  • D. Slop tank on an oil tanker
Answer: B — Pump room on an oil tanker
On an oil tanker, the cargo pump room is a designated cofferdam/void space separating the cargo tank area from the engine room machinery spaces.

4. The purpose of a cofferdam between two compartments is to?

  • A. Store tools and equipment that are necessary for the adjacent compartments
  • B. Give access to the bulkhead for inspection and repairs when the tanks are full with liquid
  • C. Keep a reserve space if the capacity of either compartment needs to be increased
  • D. Prevent different liquids from the two tanks coming in contact in case of a leak
Answer: D — Prevent different liquids from the two tanks coming in contact in case of a leak
A cofferdam is an isolating void space between two bulkheads designed to prevent liquid or vapour from leaking directly between adjacent compartments (e.g. cargo tank and engine room).

5. Which pump must always be primed?

  • A. Centrifugal pump
  • B. Reciprocating pump
  • C. Rotary pump
  • D. Gear pump
Answer: A — Centrifugal pump
Centrifugal pumps cannot pump air or create suction lift from a dry condition; therefore, their casing and suction eye must always be primed with liquid before operation.

6. What does "VECS" stand for?

  • A. Vector control system
  • B. Vapor emission control system
  • C. Very economical control system
  • D. An arrangement for release of cargo vapor
Answer: B — Vapor emission control system
VECS stands for Vapour Emission Control System, which collects and returns displaced cargo vapours ashore during tanker loading.

7. The minimum safety during EGB soot blow must be carried out with?

  • A. The OOW & Masters consent avoid soot blow during the purging time
  • B. Any time excluding the dark night hours
  • C. At 12 hours interval
  • D. At 8 hrs. interval
Answer: A — The OOW & Masters consent avoid soot blow during the purging time
Exhaust Gas Boiler (EGB) soot blowing must only be carried out with the Master's and Officer of the Watch (OOW) consent, avoiding soot blowing during purging or adverse wind conditions.

8. Why is a warning sign displayed at the gangway or access point of a barge during cargo transfer?

  • A. To indicate any health risk if applicable
  • B. To keep visitors away from the barge-No smoking, no open lights, no visitors
  • C. To designate smoking areas
  • D. To indicate if the cargo is a marine pollutant
Answer: B — To keep visitors away from the barge-No smoking, no open lights, no visitors
Warning safety notices ('No Smoking, No Naked Lights, No Unauthorized Visitors') are posted at vessel gangways and barge access points to prevent potential ignition sources in the cargo area.

9. Oxygen deficiency will begin to cause problems to personnel, do you feel to measure the atmosphere before entering clean Tanker?

  • A. Not necessary for ballast tanks
  • B. Always necessary for ballast tanks
  • C. Not necessary if the tank is filled up twice and discharged at sea
  • D. Not necessary if the tank is ventilated by external fans
Answer: B — Always necessary for ballast tanks
Atmospheric testing for oxygen (>20.9%), flammable gases (0% LEL), and toxic vapours (0 ppm) is always mandatory before anyone enters any ballast tank or void space.

10. Which party is responsible for arranging the reducers or enlarger short pieces to the manifold?

  • A. The Cargo supplier
  • B. The Cargo Surveyors
  • C. The Ships Mooring crew
  • D. The tankers staff for the operation
Answer: A — The Cargo supplier
During tanker-terminal operations, the terminal/cargo supplier is responsible for providing and fitting the required manifold reducers or spool pieces to match the shore loading arms.

11. Very light gaseous molecules such as ______ are extracted at the well head?

  • A. Methane
  • B. Butane
  • C. Propane
  • D. None of these
Answer: A — Methane
Very light gaseous hydrocarbons, primarily Methane (C1), are extracted directly at the wellhead and processed as natural gas / LNG.

12. In the event of a pneumatic remote-control failure in the inert gas plant I/P and E/P controllers, during discharge _____?

  • A. The inert gas plant must be operational within one hour of failure and the discharging may continue for this time
  • B. The discharge must be immediately halted
  • C. The discharge rate must be reduced until the plant is repaired
  • D. The venting of IG is set to maintain a predetermined pressure and the discharge can continue manually
Answer: C — The discharge rate must be reduced until the plant is repaired
If pneumatic IG pressure control fails during cargo discharge, the cargo discharge pumping rate must be immediately reduced or managed to ensure tank pressure remains safely positive.

13. When the IG plant is shutdown, the IBC cooling water should be let on the scrubber for at least ____hour(s)?

  • A. 1
  • B. 2
  • C. 3
  • D. 4
Answer: C — 3
When shutting down the inert gas plant, cooling water to the scrubber tower must be kept running for at least 3 hours (or per manufacturer instructions) to wash away acidic deposits and cool the internal packing.

14. What are consequences of a high oxygen content alarm sound during normal operation?

  • A. The plant is shut down
  • B. The pressure control valve and the flue gas isolating valve will automatically close
  • C. The alarm in Ccr will sound loud and the plant will auto stop
  • D. The deck demand valve will automatically close. The atmosphere purge valve will open and the furnace presser control valve will regulate.
Answer: D — The deck demand valve will automatically close. The atmosphere purge valve will open and the furnace presser control valve will regulate.
When high oxygen content (>8%) is detected in the inert gas supply line, the deck demand isolating valve automatically trips shut and the atmospheric vent/purge valve opens to protect cargo tanks.

15. What are these types of tanker: -LR1 (large range 1)?

  • A. 25,000-49,999DWT
  • B. 50,000-79,999 DWT
  • C. 80,000-159,999 DWT
  • D. None Of the Above
Answer: B — 50,000-79,999 DWT
LR1 (Long Range 1) product/oil tankers range in deadweight size from 50,000 to 79,999 DWT.

16. The petroleum remaining after the removal of products such as methane is termed_______?

  • A. Crude oil
  • B. Diesel oil
  • C. HFO
  • D. None Of These
Answer: A — Crude oil
The complex mixture of liquid hydrocarbons remaining after light wellhead gases (methane, ethane) are separated is termed crude oil.

17. PROTECTION for acetylene & oxygen line flame arresters & N/R flow back valves are for?

  • A. Carrying out gas welding & acetylene gas cutting work
  • B. Protection of personnel from high temp.
  • C. Preventing sparks from entering a tank or vent opening
  • D. Fire fighting
Answer: A — Carrying out gas welding & acetylene gas cutting work
Flashback arresters and non-return check valves on oxy-acetylene lines are critical safety devices preventing flame propagation back into the gas supply cylinders during gas welding/cutting.

18. In case of P/V valve for one tank is not working and the tank pressure is rising, what immediate actions are necessary usually set to follow?

  • A. Abort filling that individual tank
  • B. Try to open the valve manually
  • C. Isolate the line and change the valve from vessels tested spare
  • D. Follow all the procedures (A) + (B) &(C)
Answer: D — Follow all the procedures (A) + (B) &(C)
If an individual tank P/V valve malfunctions and tank pressure rises abnormally, the crew should abort filling that tank, verify/free the valve manually if safe, and replace it with a tested vessel spare.

19. Which topic is not required to be discussed at the pre- transfer conference?

  • A. Estimated time of finishing cargo
  • B. Details of transfer and receiving system
  • C. Emergency shutdown procedures
  • D. Identity of the product to be transferred
Answer: A — Estimated time of finishing cargo
While transfer rates, shutdown signals, and product safety details are mandatory items in the pre-transfer conference, estimated cargo completion time is an operational estimate rather than a safety checklist prerequisite.

20. Examples of inorganic chemicals such as:

  • A. Sulphuric acid
  • B. Phosphoric acid
  • C. Nitric acid
  • D. All of the above
Answer: D — All of the above
Common inorganic liquid bulk chemicals transported on chemical tankers include mineral acids such as sulphuric acid (H2SO4), phosphoric acid (H3PO4), and nitric acid (HNO3).

21. Clean ballast is normally______?

  • A. Ballast water loaded directly into a cargo tank after discharge
  • B. Ballast water into cargo tanks which have been washed crude oil
  • C. Ballast water loaded into cargo tanks which have been crude oil and water washed
  • D. Ballast water loaded in designated tanks used only for that purpose
Answer: C — Ballast water loaded into cargo tanks which have been crude oil and water washed
Clean ballast under MARPOL Annex I refers to ballast water carried in a cargo tank which has been thoroughly crude-oil-washed and water-washed such that effluent shows no visible oil trace.

22. During loading operation ullage and temp measuring equipment is showing low battery which place can we replace battery?

  • A. Can be replaced on tank area
  • B. Can be replaced near manifold area
  • C. Can be replaced at pump room entrance
  • D. Can be replaced only with indoor accommodation
Answer: D — Can be replaced only with indoor accommodation
Portable electronic measuring devices (MMC/UTI tapes) must only have their batteries changed inside safe, non-hazardous areas within the accommodation, never in hazardous deck zones.

23. Vessels in clean service normally do not have or need heater coils as the viscosity of the clean product is low enough to permit easy pumping at atmospheric temps.

  • A. Applies to all clean petroleum products (CPP)
  • B. With the exception of some lube oils & special vegetable oils
  • C. Applies to all chemicals
  • D. Applies to all condensates
Answer: B — With the exception of some lube oils & special vegetable oils
Clean petroleum products (CPP) have low viscosity and do not require heating coils, with the exception of certain heavy lubricating base oils and high-pour-point vegetable oils.

24. The foam system is operated from the _____room?

  • A. CCR
  • B. ECR
  • C. FGFC
  • D. All the above
Answer: C — FGFC
Fixed deck foam fire-extinguishing systems are operated from the Fire Gun / Foam Control (FGFC) central emergency station or designated foam room outside the cargo area.

25. MARPOL Annex VI applies:

  • A. Only the ships that fly the flag of a state that is party to MARPOL annex VI
  • B. Only to ships that visit ports of a state that is party to MARPOL annex VI
  • C. To ship with both of the above
  • D. All ships irrespective of flag or port state control requirements
Answer: C — To ship with both of the above
MARPOL Annex VI regulations apply to all ships flying the flag of a Party state, as well as ships operating in or visiting the ports and territorial waters of a State Party under Port State Control.

26. Inert gas after leaving the demister will consist of the following?

  • A. Oxygen less than 5%
  • B. SO2 less than 2.0%
  • C. Water vapor 1%
  • D. Both A & B
Answer: D — Both A & B
Properly scrubbed and demisted inert flue gas leaving the scrubber tower typically contains less than 5% oxygen by volume and negligible sulfur dioxide (<20-50 ppm).

27. How much volume of air needs to be changed in pump room?

  • A. 10 vol/hr.
  • B. 25 vol/hr.
  • C. 20 vol/hr.
  • D. 15 vol/hr.
Answer: C — 20 vol/hr.
SOLAS regulations require the mechanical ventilation system in cargo pump rooms to provide a minimum extraction rate of at least 20 air changes per hour based on total room volume.

28. Fixed foam monitors having a operating capacity_____L/min?

  • A. 1250
  • B. 1450
  • C. 1150
  • D. 1650
Answer: A — 1250
Fixed deck foam monitors on tankers are sized to deliver a standard minimum operational discharge rate of 1,250 litres per minute to effectively cover cargo manifold and deck areas.

29. In tankers, the central equipment is available either for installation in _____locations.

  • A. Hazardous
  • B. Non-hazardous
  • C. Under – pressurized
  • D. All of the above
Answer: B — Non-hazardous
Central control equipment, computers, and non-intrinsically safe electrical monitoring consoles on tankers are installed in designated non-hazardous spaces (such as the CCR or Wheelhouse).

30. The physical data of a liquid chemical can be found on_____?

  • A. MSDS (material safety data sheets)
  • B. The Information supplied by the manufacturer
  • C. ICS cargo data sheet
  • D. All of these a), b) & c)
Answer: D — All of these a), b) & c)
Comprehensive physical and chemical safety data for bulk liquid cargoes is obtained from the Material Safety Data Sheet (MSDS), manufacturer product guides, and ICS Cargo Data Sheets.

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