Tanker Operations Quiz
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Questions and Answers

What is the primary purpose of segregated ballast in a double-hull tanker?

  • To enhance vessel stability (correct)
  • To prevent pollution during a spill
  • To store fuel
  • To carry additional cargo

What does LEL stand for in the context of vapor ignition?

  • Lower explosive limit (correct)
  • Liquid evaporation level
  • Landing emergency level
  • Lethal exposure limit

Which type of valve is designed to permit flow in one direction on the discharge side of a cargo pump?

  • Butterfly valve
  • Globe valve
  • Check valve (correct)
  • Gate valve

What is the Fire Point of a liquid?

<p>Lowest temperature at which sufficient vapors ignite (D)</p> Signup and view all the answers

What does a spectacle flange do in a pipeline?

<p>Blanks off the pipeline or permits full flow (A)</p> Signup and view all the answers

What is the function of purging in tank operations?

<p>To reduce hydrocarbons to below 2% using inert gas (C)</p> Signup and view all the answers

Which characteristic differentiates double-hull tankers from single-hull tankers?

<p>Significantly lower pollution risk (D)</p> Signup and view all the answers

What is the metric ton equivalent in pounds?

<p>2,204.4 lbs (A)</p> Signup and view all the answers

What must be performed before resuming operations after a small leak at the connection between the shore hoses and the manifold?

<p>Replace the gasket at the connection (D)</p> Signup and view all the answers

What causes cavitation in a centrifugal pump?

<p>Pressure falling below vapor pressure of the cargo (B)</p> Signup and view all the answers

Which of the following is NOT a component of the Inert Gas system?

<p>Centrifugal pump for cooling (A)</p> Signup and view all the answers

What is the required oxygen level in the Inert Gas system upon discharge?

<p>No greater than 8% (A)</p> Signup and view all the answers

How many wraps should mooring lines on working drums have?

<p>3-4 wraps (C)</p> Signup and view all the answers

What is the primary function of power packs on a vessel?

<p>To operate hydraulic pumps with high pressure oil (C)</p> Signup and view all the answers

How often must visual inspections be performed as mandated by the VGP?

<p>Daily (B)</p> Signup and view all the answers

What principle do eductors operate on to create low pressure on a suction line?

<p>Venturi effect (B)</p> Signup and view all the answers

What is the primary purpose of crossover systems on oil tankers?

<p>To allow transfer between different cargo systems or segregations (A)</p> Signup and view all the answers

Where are P/V valves typically located on an oil tanker?

<p>At the top of the cargo tank (A)</p> Signup and view all the answers

What is a critical feature of the metritape gauging system?

<p>It is not affected by steam or foam (A)</p> Signup and view all the answers

What is the maximum allowed oxygen content in gas delivered by inert gas systems?

<p>8% (D)</p> Signup and view all the answers

Why is topping off petroleum cargo tanks in cold weather discouraged?

<p>It can lead to cargo overflow due to temperature rise (B)</p> Signup and view all the answers

What must be done to prevent electrostatic buildup when using a crude oil washing system?

<p>Ensure proper grounding of the equipment (A)</p> Signup and view all the answers

How should dirty ballast be handled after transfer?

<p>It must settle before being discharged (C)</p> Signup and view all the answers

What is a key characteristic of deepwell pumps?

<p>They do not reduce the number of pumps as an advantage (C)</p> Signup and view all the answers

What is the primary purpose of P/V valves on an oil tanker?

<p>To protect tanks from over or under pressurization (B)</p> Signup and view all the answers

When using a metritape gauging system, which characteristic is true about its operation?

<p>The wire only touches the core under specific conditions (C)</p> Signup and view all the answers

What are crossovers aboard an oil tanker primarily used for?

<p>To transfer cargo between segregated tanks (C)</p> Signup and view all the answers

What is a crucial requirement when cleaning tanks using a crude oil washing system?

<p>Electrostatic buildup must be prevented by maintaining air gap (A)</p> Signup and view all the answers

Which consequence may occur when topping off petroleum cargo tanks in cold weather?

<p>Subsequent overflow due to temperature rise (D)</p> Signup and view all the answers

What is an incorrect statement regarding the handling of dirty ballast after transfer?

<p>It should be sent directly to the oily water separator (D)</p> Signup and view all the answers

Which factor is NOT a benefit of a deepwell pump on an oil tanker?

<p>Reduction in the number of pumps is achievable (A)</p> Signup and view all the answers

Which condition must be met for pipeline valves concerning liquid flow to a pump?

<p>They do not increase liquid friction (A)</p> Signup and view all the answers

What occurs during the final topping off of a tanker?

<p>The likelihood of oil pollution increases. (B)</p> Signup and view all the answers

What is the primary function of a scrubber in the Inert Gas system?

<p>To remove solids and excess water from the gas. (A)</p> Signup and view all the answers

What should be done if a small leak develops during cargo oil operations?

<p>Replace the gasket at the connection. (B)</p> Signup and view all the answers

What is the role of P/V valves in the Inert Gas system?

<p>To prevent backflow of gas. (D)</p> Signup and view all the answers

Which component cools the gas before it is discharged in the Inert Gas system?

<p>Condenser. (C)</p> Signup and view all the answers

What is a requirement for the fans in the Inert Gas system?

<p>They must be capable of 125% of the discharge capacity. (D)</p> Signup and view all the answers

In case of a power loss, how will a centrifugal pump behave?

<p>Discharge pressure will decrease. (A)</p> Signup and view all the answers

What is the purpose of closed gauging in a tank?

<p>It does not allow the atmosphere to exit the tank. (D)</p> Signup and view all the answers

How does miscibility help in handling liquids?

<p>It indicates the tendency of two liquids to form a uniform blend. (B)</p> Signup and view all the answers

What is the primary consequence of the grounding of the Torrey Canyon?

<p>It led to the implementation of MARPOL 73/78. (B)</p> Signup and view all the answers

What is the primary risk associated with double hull tankers?

<p>Increased likelihood of corrosion. (C)</p> Signup and view all the answers

What factor is measured by viscosity in a liquid?

<p>The resistance to flow in a liquid. (C)</p> Signup and view all the answers

What is the purpose of a bell-mouth fitting in a cargo line?

<p>To allow suction to be taken close to the bottom of a tank. (B)</p> Signup and view all the answers

When conducting cargo transfer operations, what external factor does NOT contribute to static accumulation?

<p>A lightning storm in the vicinity of the vessel. (B)</p> Signup and view all the answers

What is the threshold limit value for short-term exposure to a substance?

<p>Concentration of a substance for exposure of less than 15 minutes. (A)</p> Signup and view all the answers

Flashcards

Double-hull tanker advantage

Significantly reduces pollution risk and allows for easier tank cleaning.

Double-hull tanker disadvantage

Higher construction and maintenance costs, potentially faster corrosion and cracking than single-hull tankers.

Purging

Introducing inert gas into a tank to lower hydrocarbon levels below 2% to prevent flammability.

Gas-freeing

A process to remove flammable gases and vapors from a space.

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Check valve

Allows flow in one direction only (typically on the discharge side of a cargo pump).

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Ullage

The space above liquid cargo in a tank, measured from the top of the liquid to a higher reference point.

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Fire point

The lowest temperature at which a liquid gives off enough vapor to ignite.

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Viscosity

A measure of a liquid's resistance to flow.

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What are water supply hoses used for?

Water supply hoses contain internal wires that act as conductors for electrical power, providing the necessary electricity for the tanker.

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Who is responsible for supervision on a tanker?

A designated person, known as the PIC (Person in Charge), must supervise all functions aboard a tanker and its associated barges.

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When is oil pollution most likely?

Topping off, the final stage of loading cargo oil, is the time with the highest risk of oil pollution due to potential spills or overflows.

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What do Power Packs do?

Power Packs provide high-pressure hydraulic oil to operate the hydraulic pumps used for various functions on the tanker.

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How many wraps for mooring lines?

Mooring lines on working drums should have about 3-4 wraps to ensure proper securement and minimize slippage.

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What to do if a leak occurs during cargo loading?

If a leak develops at the connection between the shore hoses and the manifold, immediately stop pumping and replace the leaking gasket before resuming.

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What is cavitation in a pump?

Cavitation occurs in a centrifugal pump when the pressure in the suction line falls below the vapor pressure of the cargo, leading to the formation of vapor bubbles. This can be caused by loss of prime or low pump speed.

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How does an eductor work?

Eductors use the venturi effect to create low pressure in a suction line by expelling drive fluid (usually slops) through a narrow opening. This low pressure is then used to draw up fluids for stripping operations.

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What is the purpose of a crossover on an oil tanker?

A crossover allows transfer of cargo between different tank sections or segregation zones on an oil tanker. It is used to move cargo between systems or compartments.

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How do P/V Valves protect tanks?

P/V (Pressure/Vacuum) Valves protect tanks from over-pressurization or under-pressurization. They automatically open or close to maintain a safe pressure range within the tank.

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How does a metritape gauging system work?

A metritape gauging system measures the level of cargo in tanks. It uses a stainless steel core with an exposed strip, wrapped in wire that makes contact when squeezed, providing a precise reading.

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What is the O2 percentage limit for Inert Gas systems?

Inert Gas systems must deliver gas with less than 8% oxygen (O2) to create an inert atmosphere and prevent explosions.

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What is the first consideration when discharging oil?

When discharging oil, the primary focus is on getting the bow (front) of the ship up to maintain stability and prevent the ship from listing.

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Why should you avoid excessive air in the suction line during stripping?

Excessive air in the suction line during stripping can lead to a loss of suction, making it difficult to pump out the remaining cargo.

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What is the source tank requirement for crude oil washing systems?

The source tank for cleaning machines in a crude oil washing system must have at least one meter of decanted oil removed from it.

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Why should petroleum cargo tanks not be topped off in cold weather?

Topped off cargo tanks in cold weather risk overflowing when the temperature rises due to thermal expansion of the cargo.

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What is a double-hull tanker?

A tanker with two hulls, an outer hull and an inner hull, providing extra protection against spills and making cleaning easier.

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What's the difference between purging and gas-freeing?

Purging introduces inert gas to an already inert tank to reduce hydrocarbons below 2%, preventing flammability. Gas-freeing removes flammable gases and vapors from a space, making it safe to enter.

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What is a Net Barrel?

A unit of volume equivalent to 42 gallons at 60°F.

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What is a branch line?

Piping that directs cargo from the main line to individual tanks.

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What is a Check Valve?

A valve allowing flow in one direction only, typically found on the discharge side of a cargo pump.

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What is Viscosity?

A measure of a liquid's resistance to flow.

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What is LEL?

The smallest percentage of vapor in the air that will allow for an ignitable mixture.

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What is a Spectacle Flange?

A single fitting that either blanks off a pipeline or allows full flow.

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Crossover

A system on an oil tanker that allows cargo transfer between different tank sections or segregation zones.

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P/V Valve

A valve that safeguards oil tanks from over-pressurization and under-pressurization, ensuring safe pressure levels within the tank.

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Metritape Gauging

A system used to measure cargo levels in tanks. A stainless steel core with an exposed strip, wrapped in wire making contact when squeezed, gives accurate readings.

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Inert Gas System

System supplying low-oxygen gas (less than 8%) into tanks to prevent explosions.

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Bow Up

Priority during oil discharge, ensuring the ship's front end is raised for stability.

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Excessive Air in Suction Line

Can lead to a loss of suction while stripping, making it difficult to pump out remaining cargo.

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Source Tank Decanting

Minimum requirement for cleaning machines in crude oil washing systems: one meter of decanted oil in the source tank.

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Topping Off in Cold Weather

Cargo tanks should not be fully filled in cold weather due to potential overflow when temperatures increase.

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What is Topping Off?

Topping off is the final stage of cargo loading, where the tank is filled to its capacity.

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Where are Cargo Pumps Located?

Cargo pumps are generally positioned aft (toward the rear) of the vessel, near the centerline of the tank.

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What causes Pump Cavitation?

Cavitation happens when the pressure in the suction line drops below the vapor pressure of the cargo, creating vapor bubbles.

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What is the Role of the Inert Gas System?

The Inert Gas System creates an inert atmosphere in tanks to prevent explosions by reducing oxygen levels.

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What is the Inert Gas System Inspection Frequency?

The VGP (Voluntary Guidelines for Tankers) mandates daily visual inspections of the Inert Gas System.

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Who Supervises Tanker Operations?

A designated PIC (Person in Charge) is responsible for supervising all functions aboard the tanker.

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Study Notes

Tanker Operations

  • A double-hull tanker has void space for segregated ballast.
  • Ullage is measured from the liquid's top to an above-deck datum.
  • A net barrel is equivalent to 42 gallons at 60°F.
  • Branch lines route cargo from the main to individual tanks.
  • Gate valves offer precise flow control without resistance.
  • Low Explosive Limit (LEL) is the smallest vapor percentage for ignition.
  • Check valves allow one-way flow in cargo pump systems.
  • The Torrey Canyon incident led to MARPOL 73/78.
  • Viscosity is maximum liquid resistance to flow.
  • 1 metric ton = 2204.4 lbs.
  • Vessel cargo pipelines need annual pressure testing.
  • Single pipeline fittings (spectacle flange) either blank or fully open flow.
  • Manufacturers create Safety Data Sheets (SDS).
  • Closed Gauging prevents atmospheric contact during tank measurement.
  • Oil contact with a probe sound an electric Gauging tape continuously.
  • Miscibility refers to the uniform blending of liquids.
  • Fire point is the lowest temperature for liquid ignition.
  • Jumper hoses are used for crossover between systems.
  • Hydrostatic pressure is due to fluid gravity.
  • LR1 vessel has a deadweight between 80,000-160,000.
  • Threshold limit values (TLV) specify worker exposure time (less than 15 minutes).
  • Autoignition temperature is the ignition point needing no spark.
  • Static accumulation during cargo transfer is not caused by lightning.
  • Cargo lines use bell-mouth fittings to facilitate close-to-the-bottom suction.
  • Double-hull tankers reduce pollution risks and aid cleaning.

Purging and Gas-Freeing

  • Purging introduces inert gas to reduce hydrocarbons to below 2%.
  • Gas-freeing introduces fresh air to expel vapors.
  • A crossover is a cargo system connection used for segregations, typically by Jumperhoses or Mix Masters.
  • Pressure-relief valves (P/V valves) protect tanks from overpressure or underpressure.
  • Metertape gauges use a stainless-steel core with exposed wire for liquid measurement.

Cargo Systems

  • Cargo hoses are pressure-tested annually.
  • Inert gas systems must have less than 8% oxygen.
  • Discharging oil focuses on raising the bow first.
  • Air in suction lines can hinder stripping.
  • Pipeline valves reduce liquid friction.
  • Segregated ballast loading is usually mechanical.
  • Crude oil washing systems must keep electrostatic build-up to a minimum.
  • Cold weather restricts petroleum cargo topping-off due to temperature increases.
  • Tank cleanings with portable machines should be grounded via the water supply.

Tank Operations and Maintenance

  • Hydraulic pumps are powered by power packs.
  • Mooring lines should have 3-4 wraps.
  • Leaks at hose connections/manifold require gasket replacement.
  • Centrifugal pumps don't self-prime (increasing speed leads to better discharge),
  • Cavitation is triggered by low suction line pressure and cargo vapor pressure.

Inert Gas Systems

  • Inert gas generation starts from a boiler, treated by scrubbers and cooled, and transported via fans and P/V valves.
  • Vortex separators remove moisture.
  • Visual inspection requirements are set by VGP (very likely, daily).
  • Eductor uses the Venturi effect to create low pressure for suction.

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Tanker Operations PDF

Description

Test your knowledge on tanker operations with this quiz. Learn about crucial terms and practices that ensure safe and efficient cargo handling in the maritime industry. From ullage measurements to the significance of the Torrey Canyon incident, challenge yourself with questions that cover it all.

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