MMC Upgrade Tankerman Practice Questions

Sample questions — Tankerman

Drawn from the same bank used on USCG licensing exams. Correct answers and explanations are shown — read every explanation, even for questions you get right.

1. 1. During a cargo transfer on a tank vessel, the Person-In-Charge (PIC) is primarily responsible for:

   • A.Navigating the vessel
   • B.Supervising and being in charge of the cargo transfer operation✓
   • C.Standing the engine room watch
   • D.Maintaining the cargo pumps in port only

   Why: The Person-In-Charge directs and is accountable for the safe conduct of the transfer — connecting, monitoring, and disconnecting — and must remain in charge throughout the operation.

2. 2. The emergency shutdown (ESD) signal agreed on the Declaration of Inspection is used to:

   • A.Signal the start of cargo transfer
   • B.Immediately and safely stop the transfer in an emergency✓
   • C.Request more cargo
   • D.Test the radar

   Why: Both ends must agree on the emergency-shutdown signal beforehand so that, on any hazard, the transfer can be halted quickly without causing a pressure surge or spill.

3. 3. A cargo loading/discharge plan is prepared in advance mainly to control:

   • A.The crew's overtime
   • B.Hull stresses, stability, and trim by sequencing which tanks are worked✓
   • C.The vessel's speed
   • D.The radar range scale

   Why: Loading and discharging out of sequence can impose dangerous shear forces and bending moments and upset stability/trim. The plan sequences tanks to keep stresses, list, and trim within safe limits.

4. 4. During an oil transfer, deck scuppers must be:

   • A.Left fully open to drain rainwater
   • B.Plugged or closed to keep any spill on deck✓
   • C.Removed entirely
   • D.Connected to the cargo line

   Why: Scuppers are plugged before transfer so that any spilled oil is retained on deck rather than running overboard, where it would become a reportable discharge.

5. 5. After completing a transfer, cargo hoses and loading arms are drained/blown down before disconnecting in order to:

   • A.Cool the manifold
   • B.Avoid spilling the liquid trapped in the line when the connection is broken✓
   • C.Test the cargo pump
   • D.Inert the hose

   Why: Liquid left in a hose or arm will spill when the flange is broken. Draining or blowing the line back to a tank first empties it so the connection can be parted cleanly with containment in place.

6. 6. While discharging cargo from an inerted tank, inert gas is supplied to the tank to:

   • A.Speed up the pump
   • B.Replace the volume of liquid removed and keep the tank from drawing a vacuum or air✓
   • C.Cool the cargo
   • D.Increase oxygen content

   Why: As cargo is pumped out, inert gas fills the space so the tank stays at slight positive pressure and never draws in air, which would otherwise raise oxygen content into the flammable range.

7. 7. During a cargo transfer, if the shore facility requests an emergency stop, the tankerman should FIRST:

   • A.Close the manifold valve and stop the transfer pump✓
   • B.Notify the vessel master and await instructions
   • C.Open all tank vents to relieve pressure
   • D.Switch to a different cargo tank to continue operations

   Why: In an emergency stop, the immediate action is to isolate the connection by closing the manifold valve and stopping the pump to prevent spillage or further hazardous conditions, per the vessel's cargo transfer procedures and 33 CFR 156.

8. 8. The maximum permitted oxygen content of inert gas delivered to cargo tanks under SOLAS requirements is:

   • A.5% by volume✓
   • B.8% by volume
   • C.11% by volume
   • D.2% by volume

   Why: SOLAS Chapter II-2 requires that inert gas delivered to cargo tanks must contain no more than 5% oxygen by volume, ensuring the atmosphere in the tanks remains well below the minimum oxygen concentration needed to support combustion.

9. 9. The pressure/vacuum (P/V) breaker (or P/V valve) on a cargo tank is designed to:

   • A.Open at preset limits to relieve excess pressure or vacuum and protect the tank structure from damage✓
   • B.Continuously vent cargo vapors to atmosphere during loading operations
   • C.Automatically activate the inert gas system when tank pressure drops below atmospheric
   • D.Prevent cargo from entering the vent piping during heavy weather

   Why: P/V breakers protect cargo tank structures from overpressure (which could rupture tank tops) or excessive vacuum (which could cause the tank to implode) by opening at preset pressure and vacuum limits defined in the vessel's design specifications.

10. 10. During a marine petroleum transfer, static electricity accumulation in a cargo tank is MOST hazardous when:

    • A.The tank is in the flammable range and a conductive object enters creating a discharge path✓
    • B.The tank is fully inerted with oxygen below 8% by volume
    • C.The tank is completely full with no ullage space above the cargo
    • D.The product has a flash point above 60°C (140°F) and is transferred at ambient temperature

    Why: Static discharge is dangerous only when the tank atmosphere is in the flammable range and a conductive path (such as an ungrounded probe or sample thief) creates the discharge, providing an ignition source within the explosive mixture.

11. 11. When transferring cargo through a non-conductive (plastic) hose, what is the primary static electricity concern?

    • A.Non-conductive hose cannot dissipate charge, allowing static to accumulate to discharge levels at the nozzle or connections✓
    • B.Non-conductive hose has a higher flow resistance, requiring higher pump pressure that heats the product
    • C.Non-conductive hose eliminates the need for bonding because no electrical path exists between vessel and shore
    • D.Non-conductive hose prevents cathodic protection current from protecting the hull during transfer

    Why: Non-conductive hoses do not provide a path to dissipate accumulated static charge, allowing charge to build up and potentially discharge as a spark at metal fittings or flanges where flammable vapors may be present.

12. 12. Which of the following is NOT an effective measure for controlling static electricity during petroleum cargo transfer?

    • A.Increasing pump pressure to maximum to reduce total transfer time✓
    • B.Restricting initial loading rate until the tank inlet is submerged
    • C.Bonding the vessel to the shore facility before connecting hoses
    • D.Avoiding the use of synthetic ropes or non-conductive materials near open gauging points

    Why: Increasing pump pressure and flow rate actually increases static generation through turbulence and streaming current. All other listed measures are recognized static control techniques per ISGOTT and NFPA 77.

13. 13. Under MARPOL Annex I, how long must an Oil Record Book (Part I — Machinery Space Operations) be retained after the last entry?

    • A.3 years✓
    • B.1 year
    • C.5 years
    • D.2 years

    Why: MARPOL Annex I Regulation 17 requires that Oil Record Books be retained for a period of 3 years after the date of the last entry, making them available for inspection by authorized officials.

14. 14. Under OPA 90 and 33 CFR 151.15, within what timeframe must an oil spill into navigable waters be reported to the National Response Center (NRC)?

    • A.As soon as possible, but no later than as soon as the person in charge has knowledge of the discharge✓
    • B.Within 2 hours of the discharge
    • C.Within 24 hours of the discharge
    • D.Prior to the vessel's next port call

    Why: 33 CFR 151.15 requires immediate notification to the NRC (1-800-424-8802) as soon as the person in charge has knowledge of any discharge of oil into navigable waters; delay in reporting is itself a violation.

15. 15. A tanker has just completed discharge of cargo and is preparing to wash tanks with sea water. Under MARPOL Annex I, the resulting tank washings mixed with oil residues may be discharged at sea only if which condition is met?

    • A.The vessel is more than 50 nautical miles from nearest land, proceeding en route, using an approved oil discharge monitoring and control system✓
    • B.The washing water has been treated to below 100 ppm oil content and the vessel is underway
    • C.The total quantity discharged does not exceed 1/15,000 of the total cargo capacity
    • D.The master has entered the discharge in the Oil Record Book and obtained port state approval

    Why: MARPOL Annex I Regulation 34 requires that cargo tank washings from oil tankers may only be discharged outside special areas when the vessel is 50+ nm from land, proceeding en route, using an approved oil discharge monitoring system, at a rate not exceeding 30 liters per nautical mile, and not exceeding 1/30,000 of total cargo capacity.

16. 16. Inert gas delivered to the cargo tanks by an inert gas system must have an oxygen content not exceeding what percentage by volume?

    • A.2% by volume
    • B.5% by volume✓
    • C.8% by volume
    • D.11% by volume

    Why: The inert gas supplied to the tanks must contain no more than 5% oxygen by volume. The 8% figure is a separate limit (the maximum oxygen considered acceptable inside an inerted tank atmosphere), not the quality limit of the gas being delivered.

17. 17. During cargo discharge from an inerted tank, what is the main reason for 'topping up' the tanks with inert gas?

    • A.To replace the volume of cargo pumped out and keep the tank under positive pressure✓
    • B.To lower the temperature of the remaining cargo
    • C.To raise the oxygen content of the tank atmosphere before gas-freeing
    • D.To increase the flammability of the vapor for slop-tank crude washing

    Why: As cargo is pumped out, the tank's vapor space increases, so inert gas must be added to replace that volume and keep the tank under positive pressure, preventing air ingress. Topping up does not warm cargo or raise oxygen — the goal is to keep oxygen low.

18. 18. In U.S. waters, a person in charge who observes a discharge of oil into navigable waters must immediately notify:

    • A.The local harbormaster only
    • B.The National Response Center (NRC)✓
    • C.The ship's classification society
    • D.The vessel's insurer

    Why: 33 CFR 153.203 and the Clean Water Act require any person in charge to immediately report a prohibited oil/hazardous-substance discharge to the National Response Center (1-800-424-8802). Notifying class or insurer does not satisfy the legal reporting duty.

19. 19. Before conducting an oil transfer at a facility, which of the following is a required pre-transfer step for the person in charge?

    • A.Obtain written permission from the National Response Center
    • B.Complete and sign the Declaration of Inspection confirming required checks are made✓
    • C.File a new vessel response plan with the Coast Guard
    • D.Notify the classification society of the transfer

    Why: A Declaration of Inspection (DOI) must be completed and signed by the persons in charge before an oil transfer begins, certifying that the required pre-transfer inspections and conditions are met. The NRC and class society are not involved in routine pre-transfer authorization.

20. 20. While gauging an open tank shortly after loading a static-accumulating cargo, why should a tankerman avoid wiping or using a non-conductive (e.g., plastic) gauging tape or synthetic rag?

    • A.It can introduce water into the cargo and skew the gauge
    • B.Non-conductive materials can accumulate a static charge that may discharge as a spark near the flammable vapor space✓
    • C.Synthetic materials dissolve in petroleum products
    • D.It violates the requirement to use only certified steel tapes

    Why: Non-conductive items (plastic tapes, synthetic cloth) can build and hold a static charge that may release as an incendive spark at an open ullage where flammable vapors are present. Conductive, properly bonded/grounded equipment is used to prevent charge accumulation.

Frequently asked questions

Is Tankerman on the MMC Upgrade exam?

Yes — Tankerman is one of the tested modules on the MMC Upgrade licensing exam. Candidates must score 70% on each module to pass.

How many Tankerman questions are on the MMC Upgrade exam?

The USCG draws from a bank of 192 Tankerman questions across all exams. The exact number on any single sitting varies, but Rules of the Road is typically the largest module and has the highest passing threshold (90%).

What is the best way to study Tankerman for the MMC Upgrade exam?

Work through the practice questions in this bank until you can answer them consistently above the passing threshold. Review every explanation — understanding why the wrong answers are wrong matters more than memorizing facts.