Tanker Familiarization Safety and Emergency Procedures 3 — Questions and Answers
Question 1: What is the correct procedure when entering an enclosed cargo tank that has been declared gas-free?
- Enter immediately after ventilation is complete
- Use a buddy system and maintain continuous communication with a standby person (Correct answer)
- Only the chief officer may enter alone after testing
- Wait 24 hours after gas-free certificate is issued
Correct answer: Use a buddy system and maintain continuous communication with a standby person
IMO and SOLAS require a standby person at the entrance and continuous communication throughout any enclosed-space entry.
Question 2: A tanker's Muster List (Station Bill) must be posted:
- Only in the captain's cabin for reference
- In conspicuous places throughout the vessel including crew accommodation (Correct answer)
- Solely on the bridge
- In the engine room only
Correct answer: In conspicuous places throughout the vessel including crew accommodation
SOLAS requires the Muster List to be posted in conspicuous places so every crew member can locate their emergency duties.
Question 3: Which international signal indicates a vessel is on fire and requires assistance?
- Flag November Charlie (NC) (Correct answer)
- Five or more short blasts on the ship's whistle
- Continuous sounding of the fog signal
- One prolonged blast followed by two short blasts
Correct answer: Flag November Charlie (NC)
Flag signal NC (November Charlie) is the international distress signal indicating a vessel is in distress and requires immediate assistance.
Question 4: During cargo loading on a chemical tanker, an unexpected rise in tank pressure should prompt the officer to:
- Increase the loading rate to fill the tank faster
- Slow or stop loading and investigate the cause before continuing (Correct answer)
- Open all vents immediately without further checks
- Ignore it if it stays below the relief valve setting
Correct answer: Slow or stop loading and investigate the cause before continuing
Unexpected pressure rise can indicate blocked vents, a closed valve, or overfill — all requiring immediate investigation before continuing.
Question 5: What is the minimum safe oxygen concentration level in a tank atmosphere before crew entry without SCBA?
- 18% by volume
- 20.8% by volume (Correct answer)
- 15% by volume
- 21.5% by volume
Correct answer: 20.8% by volume
IMO guidelines require at least 20.8% oxygen by volume in the atmosphere for a space to be considered safe for entry without breathing apparatus.
Question 6: On an oil tanker, an Inert Gas System (IGS) is used primarily to:
- Cool the cargo during transit in warm climates
- Maintain tank atmospheres outside the flammable range by displacing oxygen (Correct answer)
- Remove hydrogen sulfide gas from cargo tanks
- Assist in cargo pump priming
Correct answer: Maintain tank atmospheres outside the flammable range by displacing oxygen
IGS introduces inert gas (usually flue gas or nitrogen) into cargo tanks to keep oxygen levels too low to support combustion.
Question 7: After abandoning a tanker, survivors in a lifeboat should move away from the vessel because:
- The radio signal is stronger further from the tanker
- Cargo vapors, fire, or explosion may still pose a hazard (Correct answer)
- Lifeboat engines perform better in open water
- Rescue helicopters require a minimum approach distance
Correct answer: Cargo vapors, fire, or explosion may still pose a hazard
A burning or leaking tanker can explode or discharge flammable vapors at the surface, creating lethal hazards for nearby survivors.
Tanker Familiarization Safety and Emergency Procedures 3
What is the correct procedure when entering an enclosed cargo tank that has been declared gas-free?