OCTCO/OCTF exit exam questions and answers — Set 1 — Oil and Chemical Tanker Cargo Operations
Set 1 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 1 — 30 OCTCO/OCTF exit exam questions with answers
1. What MARPOL Annex regulates prevention of oil pollution from tankers?
- A. MARPOL Annex I
- B. MARPOL Annex II
- C. MARPOL Annex V
- D. MARPOL Annex III
2. What is the maximum oxygen content allowed in inert gas supplied to cargo tanks?
- A. 21%
- B. 5% by volume (max 8% inside tanks)
- C. 0%
- D. 15%
3. What operation uses crude oil jets to clean sludges from tank walls during discharge?
- A. Crude Oil Washing (COW)
- B. Water flushing
- C. Steam cleaning
- D. Solvent soaking
4. What condition is mandatory before starting Crude Oil Washing (COW)?
- A. Boiler off
- B. Tank open to air
- C. Dry dock
- D. Cargo tank must be inerted with O2 < 8%
5. What system monitors and controls oily water discharge overboard from slop tanks?
- A. Salinometer
- B. OWS 15 ppm alarm
- C. Echo sounder
- D. Oil Discharge Monitoring and Control System (ODMCS)
6. What is the maximum instantaneous rate of oil discharge allowed outside Special Areas under MARPOL Annex I?
- A. 100 L/nm
- B. Zero
- C. 30 liters per nautical mile
- D. 15 ppm
7. What device stops hydrocarbon gas backflowing from cargo tanks into the machinery space?
- A. Butterfly valve
- B. Deck Water Seal and Non-Return Valve
- C. Fan
- D. Flame screen
8. What instrument measures flammable vapor concentration as a percentage of LEL?
- A. Explosimeter (Combustible Gas Indicator)
- B. Dip tube
- C. Oxygen Analyzer
- D. Refractometer
9. What is Reid Vapor Pressure (RVP)?
- A. Standard measure of crude oil vapor pressure at 100°F (37.8°C)
- B. Air pressure
- C. Hydraulic pressure
- D. Steam pressure
10. What device protects oil cargo tanks against overpressure or vacuum structural damage?
- A. High-velocity Pressure/Vacuum (P/V) valve
- B. Gate valve
- C. Quick closing valve
- D. Storm valve
11. What does ISGOTT stand for?
- A. International Safety Guide for Oil Tankers and Terminals
- B. Integrated Offshore Safety
- C. Indian Safety Group
- D. System for Gas Safety
12. What is the function of an Inert Gas Scrubber tower?
- A. Cool flue gas and remove soot and SO2 particles
- B. Generate oxygen
- C. Separate oil and water
- D. Heat oil
13. What is Load on Top (LOT) procedure?
- A. Pumping without sounding
- B. Overfilling tanks
- C. Heavy cargo over light cargo
- D. Decanting clean water under settled slops and loading fresh crude directly on top
14. What risk occurs if static electricity accumulates during initial filling of an un-inerted tank?
- A. Corrosion
- B. Electrostatic spark ignition causing tank explosion
- C. Freezing
- D. Cavitation
15. What is the max initial loading rate velocity for static accumulator oils before inlet pipe is submerged?
- A. No limit
- B. 1 meter per second
- C. 10 m/s
- D. 50 m/s
16. What safety system automatically shuts down cargo pumps and closes valves in emergencies?
- A. Emergency Shutdown System (ESD)
- B. Windlass brake
- C. Boiler valve
- D. Bilge valve
17. What equipment measures hydrocarbon vapor concentration in zero-oxygen inert atmospheres?
- A. Catalytic explosimeter
- B. Hydrometer
- C. Litmus paper
- D. Tankscope / Infrared Gas Analyzer
18. What is total oil discharge limit for existing tankers during ballast voyage under MARPOL Annex I?
- A. 1/1,000
- B. 100 m3
- C. Zero everywhere
- D. Max 1/30,000 of total cargo carried on previous voyage
19. What is the function of stripping pumps during cargo discharge?
- A. Drain remaining oil liquid from tank bottoms and suction lines
- B. Cool main deck
- C. Generate steam
- D. Pump ballast into fuel tanks
20. What safety document is signed by ship officer and shore representative prior to cargo transfer?
- A. Waybill
- B. Crew Agreement
- C. Custom Clearance
- D. Ship / Shore Safety Checklist (SSSCL)
21. What gas present in crude oil vapor is highly toxic with rotten egg smell at low levels?
- A. Methane
- B. Nitrogen
- C. Hydrogen Sulfide (H2S)
- D. Carbon Dioxide
22. What is modern TLV-TWA exposure limit for Hydrogen Sulfide (H2S)?
- A. 1 ppm to 5 ppm
- B. 1000 ppm
- C. 5000 ppm
- D. 100 ppm
23. What device isolates cargo tank vapor space while maintaining pressure control?
- A. Sounding cap
- B. Open stack
- C. Pressure/Vacuum (P/V) breaker or P/V valves
- D. Scupper plug
24. What requirement applies to double hull tankers under MARPOL Annex I?
- A. Wood lined hold
- B. Single skin side
- C. Open bilge
- D. Double bottom and wing ballast tanks separating cargo tanks from outer hull
25. What action is taken if inert gas oxygen content exceeds 8% during cargo discharge?
- A. Open tank lids
- B. Stop cargo discharge immediately and rectify IG plant fault
- C. Drain scrubber
- D. Double discharge speed
26. What is purging on an oil tanker?
- A. Pumping oil to shore
- B. Ballasting
- C. Introducing inert gas into an inerted tank to reduce hydrocarbon concentration before gas freeing
- D. Washing with seawater
27. What is the function of Oil Record Book (Part II) on oil tankers?
- A. Mandatory log of cargo operations, ballasting, COW, slop discharges, and ODMCS
- B. Food inventory
- C. Overtime record
- D. Engine oil log
28. What type of pump is most commonly used as main cargo pump on crude oil tankers?
- A. High-capacity steam turbine or motor driven centrifugal pump
- B. Gear pump
- C. Hand piston pump
- D. Diaphragm pump
29. What safety feature is mandatory on cargo pump room ventilation systems?
- A. Air recirculation
- B. Continuous extraction ventilation (at least 20 air changes per hour) under negative pressure
- C. Small fan
- D. No ventilation
30. What is auto-ignition temperature of a flammable liquid?
- A. Vacuum boiling point
- B. Sea temp
- C. Lowest temperature at which vapor ignites spontaneously without external spark
- D. Freezing point
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