CHEMCO exit exam questions and answers — Set 5 — Advanced Training for Chemical Tanker Cargo Operations
Set 5 of the Advanced Training for Chemical Tanker Cargo Operations (CHEMCO) exit exam bank — 30 of 663 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.
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Set 5 — 30 CHEMCO exit exam questions with answers
1. Working instructions specifying the manner in which the ship is to be loaded and ballasted to avoid unacceptable stresses in the vessel’s structure is required for tankers:
- A. Greater than 50 metres in length
- B. Greater than 75 meters in length
- C. Greater than 100 meters in length
- D. Greater than 150 meters in length
Answer: D — Greater than 150 meters in length
The Load Line Convention regulation 10 and SOLAS require ships over 150 metres in length to carry an approved loading manual and loading instrument with instructions to avoid unacceptable hull stresses during loading and ballasting.
2. A self-contained breathing apparatus is used to
- A. make underwater repairs to barges
- B. determine if the air in a tank is safe for men
- C. enter areas that may contain dangerous fumes or lack oxygen
- D. resuscitate an unconscious person
Answer: C — enter areas that may contain dangerous fumes or lack oxygen
A self-contained breathing apparatus supplies breathable air from a cylinder carried by the wearer, allowing safe entry into spaces with toxic or flammable vapours or oxygen deficiency, for example for rescue or firefighting. It is not used for testing the atmosphere.
3. Part A of the the ISGOTT Ship/Shore Safety Check-List provides operational procedures for:
- A. Transfer of bulk liquids, physical checks
- B. Transfer of bulk liquids – elements to be verified verbally
- C. Additional considerations for Bulk Liquid Chemicals
- D. Additional considerations for Bulk Liquefied Gases
Answer: A — Transfer of bulk liquids, physical checks
Part A of the ISGOTT Ship/Shore Safety Checklist covers the general checks for transfer of bulk liquids that are physically verified by ship and shore representatives, such as moorings, access, communications and emergency arrangements.
4. The approval period for a shipboard Oil Pollution Emergency Plan expires after
- A. two years
- B. three years
- C. four years
- D. five years
Answer: D — five years
A vessel oil spill response plan under US OPA 90 rules in 33 CFR 155 is approved for a period of five years, after which it must be resubmitted for approval. The plan must also be reviewed annually by the operator.
5. Which of the listed functions is the purpose of a gas scrubber in an inert gas generation system?
- A. Cools the inert gas.
- B. Maintains the oxygen content at 5% by volume.
- C. Bleeds off static electricity in the inert gas.
- D. Maintains flow to the water seal on the gas main.
Answer: A — Cools the inert gas.
The scrubber cools the hot flue gas from the boiler uptake by spraying seawater through it, while also removing soot and most of the sulphur dioxide. Cooling is its main function, since hot gas cannot be delivered to the cargo tanks.
6. With an increase in temperature the volume of flammable and combustible liquids____.
- A. expands
- B. contracts
- C. remains constant
- D. remains constant if pressure remains constant
Answer: A — expands
Flammable and combustible liquids expand as their temperature rises, which is why ullage must be left in cargo tanks to allow for thermal expansion during the voyage and why volume measurements are corrected to standard temperature.
7. The standard unit of liquid volume used in the petroleum industry, as well as the tanker industry, is a __________.
- A. barrel
- B. drum
- C. gallon
- D. liter
Answer: A — barrel
The barrel, equal to 42 US gallons or about 159 litres, is the standard unit of liquid volume in the petroleum and tanker industries for cargo quantities and bills of lading.
8. Combustible gas indicators operate by drawing an air sample into the instrument
- A. over an electrically heated platinum filament
- B. where it is mixed with nitrogen
- C. where it is ignited by a sparking device
- D. where its specific gravity is measured
Answer: A — over an electrically heated platinum filament
A catalytic combustible gas indicator draws the sample over an electrically heated platinum filament. Combustible gas burns on the filament, raising its temperature and resistance, which unbalances the Wheatstone bridge and gives a reading in percent LEL.
9. After each reading of an oxygen indicator, the instrument should be purged with
- A. CO2
- B. fresh air
- C. the tested compartment's air
- D. water
Answer: B — fresh air
After each reading the oxygen analyser should be purged with fresh air so that the sensor returns to 20.9% and residual sample gas does not affect the next measurement or damage the cell.
10. When the cofferdam to be purged to check the leakage and remove the leaked oil?
- A. Before starting the cargo operation
- B. Before starting the cargo operation and after the cargo operation is completed
- C. During the cargo operation
- D. After the cargo operation is completed
Answer: B — Before starting the cargo operation and after the cargo operation is completed
Cofferdams around cargo spaces, such as at pump seals, should be purged and checked for leakage before cargo operations commence and again after completion, so that any leaked cargo is detected and removed and does not create a hazard or contamination.
11. How the Framo pump has almost eliminated cavitation for free flowing liquids?
- A. Volute casing is designed in such a way, that its smoothness avoids cavitation
- B. The backwards curved vanes eliminate the cavitation
- C. The hydrofoil design of the curved vanes, eliminate cavitation
- D. Since the suction pipe is eliminated, cavitation is also eliminated for liquids with free flow
Answer: D — Since the suction pipe is eliminated, cavitation is also eliminated for liquids with free flow
A Framo submerged pump sits at the bottom of the tank with the impeller immersed in cargo, so there is no long suction pipe and the liquid flows directly into the impeller. With no suction lift, cavitation is practically eliminated for free-flowing liquids.
12. Select the correct statement.
- A. Pressure type vacuum valves can prevent Backflow.
- B. Dynamic pressure is a function of the fluid velocity and its density.
- C. The water reservoir of a self-priming pump may be at the back of the impeller.
- D. Stripping pumps are not of the self-priming type.
Answer: B — Dynamic pressure is a function of the fluid velocity and its density.
Dynamic pressure is the kinetic energy per unit volume of a moving fluid, equal to half the density multiplied by the square of the velocity. It therefore depends on fluid velocity and density.
13. Why the cargo pump in the Framo cannot be overloaded?
- A. The pressure of hydraulic oil to the motor driving the cargo pump is designed in such a way that, the flow is always kept constant
- B. The pressure of hydraulic oil to the motor driving the cargo pump is designed in such a way that, the pump runs at the optimum speed
- C. The pressure of hydraulic oil to the motor driving the cargo pump is designed in such a way that, when the pump over speeds, the flow of oil is reduced
- D. The pressure of hydraulic oil to the motor driving the cargo pump is designed in such a way that, the pressure can run the pump at 75% of the capacity
Answer: B — The pressure of hydraulic oil to the motor driving the cargo pump is designed in such a way that, the pump runs at the optimum speed
In a Framo hydraulic system the hydraulic pressure supplied to the cargo pump motor is limited so that the pump runs at its optimum speed. Because the drive pressure is controlled, the pump cannot be driven beyond its design load and overloading is prevented.
14. Normally how much hydraulic oil is required to run the Framo portable pump?
- A. 360 litres per min
- B. 250 litres per min
- C. 140 litres per min
- D. 90 litres per min
Answer: C — 140 litres per min
Framo portable hydraulic pumps are typically driven by a hydraulic oil flow of around 140 litres per minute from the ship's power pack or a portable unit, according to the manufacturer's operating data.
15. Select the correct point regarding the operation of the portable pumps?
- A. Before using portable pump, rig the pump on the deck and while pumping, lower the hose in the tank
- B. When the liquid cargo level goes down, lower the hose accordingly, keeping the rigged pump on the deck
- C. Make sure that the portable pump is completely submerged and lowered till the bottom of the tank and then start the pumping operation
- D. Ensure that only the lower half of the pump is submerged and is lowered as the cargo level falls.
Answer: D — Ensure that only the lower half of the pump is submerged and is lowered as the cargo level falls.
A portable submersible pump should be lowered so that it is partly submerged and then lowered progressively as the cargo level falls. This keeps the pump inlet immersed, avoids overloading and prevents the pump resting on the tank bottom and drawing sediment.
16. What is the pressure of the hydraulic oil in the return side after running the hydraulic motor?
- A. Around 3 Bar
- B. Around 10 bar
- C. Around 15 bar
- D. Above 15 bar
Answer: A — Around 3 Bar
In a Framo hydraulic circuit the return line from the hydraulic motor operates at a low pressure of around 3 bar, sufficient to return oil to the tank and keep a positive pressure on the motor return side.
17. Normally what is the discharge capacity of Framo portable pumps?
- A. 150 cubic meter per hour
- B. 100 cubic meter per hour
- C. 70 cubic meter per hour
- D. 200 cubic meter per hour
Answer: C — 70 cubic meter per hour
Framo portable hydraulic cargo pumps typically have a discharge capacity of about 70 cubic metres per hour, which makes them suitable for emergency transfers and stripping rather than bulk discharge.
18. In a centrifugal pump:
- A. The discharge side has a negative pressure.
- B. The fluid moves in a direction opposite to the impeller.
- C. The fluid moves in the same direction as the impeller.
- D. The width of the discharge pipeline decreases outwards.
Answer: C — The fluid moves in the same direction as the impeller.
In a centrifugal pump the liquid is carried round by the impeller vanes and thrown outward in the same direction of rotation, gaining velocity that is converted to pressure in the volute casing.
19. Where is cofferdam in Framo pumps?
- A. On the cargo pump side of the seal
- B. On the hydraulic motor side of the seal
- C. On both pump and motor side of the seal
- D. Not on the pump end or the motor end
Answer: C — On both pump and motor side of the seal
In a Framo submerged pump a cofferdam separates the cargo seal from the hydraulic oil seal, so it lies on both the pump and motor side of the seals. Any leakage of cargo or hydraulic oil collects in the cofferdam and is detected by purging.
20. Bernoulli’s principle states that:
- A. pressure (P) x height (H) is a constant
- B. height (H) x velocity (V) is a constant
- C. pressure (P) x velocity (V) is a constant
- D. pressure (P) x density (D) is a constant
Answer: C — pressure (P) x velocity (V) is a constant
Bernoulli's principle relates pressure and velocity in a flowing fluid: when velocity increases, static pressure decreases, so pressure and velocity energy together remain constant along a streamline. The bank expresses this relationship between pressure and velocity.
21. How the speed of the portable pump can be varied?
- A. Portable pump speed cannot be varied
- B. Using the flow control valve of the main cargo pump
- C. By varying the speed of the feed pump
- D. The portable pump is always rigged with its own flow control valve which is used for speed variation
Answer: D — The portable pump is always rigged with its own flow control valve which is used for speed variation
A portable hydraulic pump is rigged with its own hydraulic flow control valve. Adjusting this valve changes the hydraulic oil flow to the motor and therefore the pump speed and output.
22. What kind of pumps can move extremely thick fluids like sludge without clogging ?
- A. Rotary vane pumps
- B. Reciprocating pumps
- C. Deep well pumps
- D. Screw pumps
Answer: D — Screw pumps
Screw pumps are positive displacement rotary pumps that move fluid smoothly along the meshing screw cavities with low shear, so they can handle very viscous fluids such as sludge and heavy oils without clogging.
23. What is the pressure of the hydraulic oil in the inlet side for running the hydraulic motor?
- A. Around 50 Bar
- B. Around 170 bar
- C. Around 100 bar
- D. Around 25 bar
Answer: B — Around 170 bar
In a Framo hydraulic system the supply pressure to the cargo pump hydraulic motor is typically around 170 bar at full load, as given in the manufacturer's operating data.
24. The reciprocating pump creates a suction effect when there is a
- A. decrease in pressure
- B. increase in pressure
- C. no change in pressure
- D. decrease or an increase in pressure
Answer: A — decrease in pressure
On the suction stroke of a reciprocating pump the piston moves to increase cylinder volume, creating a pressure drop below atmospheric. The higher pressure on the liquid surface pushes liquid into the cylinder, producing the suction effect.
25. What happens within the hull girder due to the development of bending moment due to stresses on hull are the following: find a statement that provides structural strength to the hull girder
- A. A bending stress is developed at every transverse section of the hull.
- B. The universal expression for bending stress is:bending stress = (bendingmoment)/(section modulus)
- C. Maximum bending moment at the midship means that the bending stress at the midships will be the maximum, and hence the deciding factor for the design.
- D. The bending stress at the midship is kept within safe limits by designing the midship section with a sufficient section modulus.
Answer: D — The bending stress at the midship is kept within safe limits by designing the midship section with a sufficient section modulus.
Bending stress equals bending moment divided by section modulus, and the bending moment is usually largest amidships. Designing the midship section with sufficient section modulus keeps the stress within safe limits, which is what provides the hull girder with its structural strength.
26. When doing an enclosed space rescue, the person in charge must co- ordinate the rescue:
- A. From inside the space
- B. From the Bridge
- C. From outside the space
- D. From the Engine Control Room
Answer: C — From outside the space
The person in charge of an enclosed space rescue must remain outside the space to coordinate the team, maintain communication with the rescuers and the bridge, and control the operation. Entering would remove the overall control and add another person at risk.
27. Select the correct statement.
- A. A tanker with a defective oil discharge monitoring and control system may undertake one ballast voyage before proceeding to a repair port, under certain circumstances.
- B. A tanker with a defective oil discharge monitoring and control system cannot undertake a ballast voyage.
- C. A tanker with a defective oil discharge monitoring and control system need only repair the system before the next annual MARPOL survey of the IOPP Certificate.
- D. A tanker with a defective oil discharge monitoring and control system may undertake one ballast voyage and one loaded voyage before proceeding to a repair port, provided permission is taken from the relevant authority.
Answer: A — A tanker with a defective oil discharge monitoring and control system may undertake one ballast voyage before proceeding to a repair port, under certain circumstances.
MARPOL Annex I regulation 31 and the associated guidelines allow a tanker with a failed ODME to undertake one ballast voyage before proceeding to a repair port, subject to the Administration's conditions, provided the failure is recorded in the Oil Record Book.
28. Control of Entry into Enclosed Spaces; identify the most important statement which is a key measure to safe entry
- A. Prior to entry into an enclosed space, a risk assessment should be completed to identify the potential hazards and to determine the safeguards to be adopted.
- B. The safe working practice should be documented and approved by the responsible officer before being countersigned by the master, who confirms that the practice is safe and in compliance with the ship’s Safety Management System.
- C. The permit, or other enabling document, should be sighted and completed by the person entering the space, prior to entry.
- D. The controls required for safe entry vary with the task being performed and the potential hazards identified during the risk assessment.
Answer: A — Prior to entry into an enclosed space, a risk assessment should be completed to identify the potential hazards and to determine the safeguards to be adopted.
The key measure for safe enclosed space entry, as set out in IMO Resolution A.1050(27) and ISGOTT, is a risk assessment completed before entry to identify the hazards and determine the safeguards, such as ventilation, atmosphere testing, PPE and rescue arrangements.
29. Lung inflammation will cause:
- A. Breathlessness and drowsiness
- B. Breathlessness and confusion
- C. Breathlessness and a dry cough
- D. Breathlessness and slurred speech
Answer: C — Breathlessness and a dry cough
Inflammation of the lungs, for example from inhaling irritant or toxic cargo vapours, typically causes breathlessness and a dry cough as the airways become irritated, as described in the IMO Medical First Aid Guide.
30. The Convention that allows States to intervene in a pollution incident at sea is the
- A. MARPOL Convention
- B. SOLAS Convention
- C. CLC Convention
- D. Intervention Convention
Answer: D — Intervention Convention
The International Convention relating to Intervention on the High Seas in Cases of Oil Pollution Casualties, 1969, gives coastal States the right to take measures on the high seas to prevent, mitigate or eliminate grave and imminent danger of pollution from a maritime casualty.
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