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100+ Free BD Marine Engineer Class 4 (Coastal CE) Practice Questions
Bangladesh DoS Marine Engineer Officer Class 4 (Chief Engineer Officer - Coastal Voyage) Certificate of Competency practice questions are available now; exam metadata is being verified.
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Sample BD Marine Engineer Class 4 (Coastal CE) Practice Questions
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1What is a feeler gauge used for in engine room workshop practice?
A.Measuring electrical voltage across a circuit
B.Measuring small clearances or gaps between two surfaces
C.Measuring the temperature of a bearing
D.Measuring the specific gravity of battery electrolyte
Explanation: A feeler gauge is a set of thin metal blades of graduated thickness used to measure small clearances, such as piston ring side clearance, valve tappet clearance, or bearing running clearance. The correct blade is selected until it just fits snugly in the gap.
2Which tool is used to accurately measure the outside diameter of a shaft to within a hundredth of a millimetre?
A.Feeler gauge
B.Vernier caliper only
C.Micrometer screw gauge
D.Steel rule
Explanation: A micrometer screw gauge gives precise external (or internal/depth) measurements, typically to 0.01 mm, using a calibrated screw thread. It is the standard workshop instrument for checking shaft diameters, wear limits, and bearing clearances with high accuracy.
3What does the Total Base Number (TBN) of a diesel engine's lubricating oil indicate?
A.The oil's resistance to foaming at high temperature
B.The oil's ability to neutralise acidic combustion by-products
C.The oil's viscosity at operating temperature
D.The oil's flash point
Explanation: TBN measures the reserve alkalinity in lubricating oil, which neutralises acidic products formed from combustion (especially with high-sulphur fuel) before they can corrode cylinder liners, piston rings, and bearings. A falling TBN during oil analysis warns that the oil's acid-neutralising capacity is being used up.
4What condition is most likely to cause cavitation damage in a centrifugal pump?
A.Excessive suction pressure on the pump inlet
B.Insufficient suction head causing local vaporisation of the liquid
C.Running the pump at too low a speed
D.Using an oversized discharge pipe
Explanation: Cavitation occurs when the pressure at the pump's suction eye drops below the liquid's vapour pressure, causing vapour bubbles to form and then collapse violently as they reach the higher-pressure discharge side. This is usually caused by insufficient suction head, a blocked strainer, or excessive suction lift, and the collapsing bubbles erode impeller and casing surfaces.
5What is the main function of a stuffing box fitted around a propeller shaft where it passes through the stern tube?
A.To lubricate the propeller blades
B.To prevent seawater from entering the vessel along the rotating shaft
C.To reduce the shaft's rotational speed
D.To measure the shaft's torque
Explanation: The stuffing box (shaft seal) around the stern tube uses packing or mechanical seals to prevent seawater from leaking into the engine room along the rotating propeller shaft, while still allowing the shaft to turn freely. It is checked regularly for gland leakage and packing wear.
6How does a sacrificial zinc anode protect a ship's hull and sea water piping from corrosion?
A.It coats the metal surface with a protective paint film
B.It absorbs vibration that would otherwise crack the metal
C.It corrodes preferentially because it is more electrochemically active than the surrounding metal
D.It increases the water temperature to reduce rust formation
Explanation: Sacrificial anodes such as zinc or aluminium are more anodic (electrochemically active) than steel. When connected in the same electrolyte, the anode corrodes preferentially, supplying electrons that protect the more valuable steel hull or piping from galvanic corrosion. Anodes must be inspected and replaced as they waste away.
7Why is a bilge high-level alarm fitted in the engine room?
A.To warn of excessive fuel oil viscosity
B.To warn the watchkeeper of a rising water level that could indicate flooding or a leak
C.To indicate when the main engine has overheated
D.To signal when the anchor is dragging
Explanation: A bilge high-level alarm alerts the engineer on watch that water is accumulating faster than normal in the bilge well, which may indicate a pipe leak, gland leakage, or hull ingress. Early warning allows the crew to investigate and pump out the bilge before the situation becomes dangerous.
8Which of the following best describes a key difference between ferrous and non-ferrous metals used in engine room components?
A.Ferrous metals always melt at a lower temperature than non-ferrous metals
B.Ferrous metals contain iron and are generally magnetic, while non-ferrous metals do not contain iron and are generally non-magnetic
C.Non-ferrous metals cannot be welded under any circumstances
D.Ferrous metals are always lighter than non-ferrous metals
Explanation: Ferrous metals (such as cast iron and steel used for cylinder liners and engine blocks) contain iron and are generally magnetic, while non-ferrous metals (such as copper, brass, and bronze used for pipework and bearings) contain no iron and are generally non-magnetic. This distinction affects corrosion resistance, strength, and suitability for different engine components.
9Why must a torque wrench be used when tightening cylinder head or bearing cap bolts?
A.To measure the temperature of the bolt during tightening
B.To apply a specified, even tightening force so that gaskets seal properly and bolts are not over- or under-stressed
C.To count the number of threads on the bolt
D.To electrically insulate the joint
Explanation: A torque wrench applies a precisely controlled rotational force to a fastener, ensuring bolts are tightened to the manufacturer's specified value. This prevents under-tightening (which can cause leaks or loosening from vibration) and over-tightening (which can stretch or shear the bolt and damage the gasket or joint face).
10What is the primary purpose of a gasket fitted between two mating flanges or covers?
A.To increase the electrical conductivity between the two parts
B.To provide a compressible seal that fills surface irregularities and prevents fluid or gas leakage
C.To reduce the weight of the assembly
D.To act as a bearing surface for a rotating shaft
Explanation: A gasket is a compressible material placed between two mating surfaces to fill microscopic irregularities and maintain a leak-tight seal against the fluid or gas pressure inside, even though the two surfaces are not perfectly flat or smooth. Gasket material is chosen based on the fluid, temperature, and pressure involved.
About the BD Marine Engineer Class 4 (Coastal CE) Practice Questions
Verified exam format metadata for Bangladesh DoS Marine Engineer Officer Class 4 (Chief Engineer Officer - Coastal Voyage) Certificate of Competency is pending. The practice questions above remain available while official exam length, timing, passing score, fee, and administrator details are reviewed.