3/3 Common Interview Questions for maritime students (Technical engine)

TECHNICAL (ENGINE)
1. What is Marine Engineering?
The Bachelor of Science in Marine Engineering is a 4 year degree program that centers on the construction, operation, and maintenance of different kinds of marine vessels such as cargo ships, cruise ships, fishing boats, battleships and submarines.
This program aims to provide students with the knowledge and skills that will enable them to operate and maintain the different machineries installed in marine vessels, including the propulsion plant, adjunct and auxiliary machinery, electrical and refrigeration systems.

2. What are the duties and responsibilities of an engine cadet on board?

Chief Engineer- is responsible to the master for the satisfactory operation of all machinery and equipment.
2nd Engineer- Is responsible for the practical upkeep for the Chief Engineer to keep a watch. Under incharge/instruction/supervise of the Chief Engineer. Like Planning of works, Repair and maintenance, and incharge of the engine room.
3rd and 4th Engineer- are usually senior watchkeepers or engineers in charge of the watch. Follow instruction of the 2nd Engineer. Repair and maintenance. Watchkeeping engineers.
Engine Cadet-is the most junior personnel in Engine department. He is responsible to take a Job order to 2nd Engineer



3. Differentiate diesel and gas engine.

They are both internal combus­tion engines designed to convert the chemical energy into mechanical energy

Diesel Engine-Mixed with air
-with fuel injector that produce combustion. To burn, heat of compression must be applied
Gas Engine- Using spark plug to produce heat.

4. What is Four Stroke Diesel Engine?
4 cycles 2 revolution

5. What is Two Stroke Diesel Engine?
2 cycles 1 revolution



6. What is the difference of Four Stroke from a Two Stroke and vice verse?
4 stroke- 4 cycles 2 revolution
2 stroke- 2 cycles 1 revolution

7. Explain the cycles of four stroke and two stroke.

8. The advantages and disadvantages of Four-Stroke and Two-Stroke.

A two stroke engine can produce twice the amount of power (and makes twice as much noise).Two stroke engines are simpler and cheaper to manufacture compared to four stroke engines because of their simpler design.
Four stroke engines are longer lasting than two stroke engines that don’t have a dedicated lubricating system. Four stroke engines are more fuel efficient and environmentally friendly when compared to two stroke engines that also create an unpleasant smell.

9. What is Refrigeration?
Refrigeration is a process of moving heat from one location to another.



10. Draw and explain the refrigeration cycle.
Compressor-compresses the refrigerant
Oil water separator-remove oil and water
Receiver (optional)
Evaporator-place where absorption of heat occurs
Condenser-cools refrigerant after compressing
Expansion valve-controls the flow of refrigerants to the evaporator

11. What is the difference between a purifier and clarifier?
Both are used in a separation process
Purifier- two liquids of different densities are separated using a centrifuge
Clarifier-when the same centrifuge is used to separate solid impurities from the fuel.

12. What are pumps and cite the types of pumps and their use?

A pump is a device that moves fluids (liquids or gases), or sometimes slurries, by mechanical action. Pumps can be classified into three major groups according to the method they use to move the fluid: direct lift, displacement, and gravity pumps.

Positive displacement pump- No more priming ex. Gear pump, screw pump, reciprocating pump.

Rotor dynamic pump- Needs Priming ex. Centrifugal Pump.



13. Parts of the Main Engine.
Camshaft, Crankshaft, Piston, Inlet and outlet valve, combustion space, Connecting Rod, Cylinder Liner, Cylinder Case.

14. Define the parts of the main engine and their functions.

 

15. What is series?
A series circuit has more than one resistor (anything that uses electricity to do work) and gets its name from only having one path for the charges to move along. It is that components are connected end-to-end in a line to form a single path for electrons to flow

16. What is parallel?
A parallel circuit has more than one resistor (anything that uses electricity to do work) and gets its name from having multiple (parallel) paths to move along. There are many paths for electrons to flow, but only one voltage across all components.

17. The difference between a series and parallel?
18. Is a Christmas lights a series connection? Series

19. What the difference between a direct current and alternating current?
DC is defined as the “unidirectional” flow of current; current only flows in one direction.
Alternating current describes the flow of charge that changes direction periodically.



20. Cite examples of direct and alternating current?
Your Refrigerator, washer and dryer, oven, lights, use AC.
Your cell-phone, wireless phone, flashlight use DC.

21. Examples of machine shop tools and their functions
Drilling- is a cutting process that uses a drill bit to cut or enlarge a hole of circular cross-section in solid materials.
Welding- used to join to two metals.
Lathe- is a machine tool that rotates the workpiece on its axis to perform various operations such as cutting, sanding, knurling, drilling, or deformation, facing, turning, with tools that are applied to the workpiece to create an object with symmetry about an axis of rotation.
Grinder- is a grinding tool with abrasive wheel

22. What is welding?
Welding is a fabrication or sculptural process that joins materials, usually metals or thermoplastics, by causing fusion, which is distinct from lower temperature metal-joining techniques such as brazing and soldering, which do not melt the base metal.

Boiler-is a device used to create steam by applying heat energy to water. Produce steam used also for heating fuel oil, lube oil, and other plants to maintain the viscosity for combustion.

Types of boiler
Fire tube – consist of large tubes for low pressure heating plants and the product of combustion pass through the inside of the tubes, and outside the tubes is surrounded by water.
Water tube – constructed with small tubes and efficient production of higher steam pressure, where the water is contained inside the tubes, with product of combustion passing around the outside of the tubes.



Hand Tool – hand tool is any tool that is not a power tool – that is, one powered by hand rather than by an engine.
Ex. Hammer, Pliers, screwdrivers, Chisel, Star screw, hacksaw, wrenches

Power Tool is a tool that is actuated by an additional power source and mechanism other than the solely manual labour used with hand tools
Ex. Grinder, drills, chainsaw, joiners, jointers, lathes, chainsaw, Impact wrench, Pneumatic wrire brush, jet chisels, chainblock, nail gun



 

Basic Conversion
1 foot (ft) – 12 inches
1 Inch=2.54cm
1 yard (yd)-3 feet
1 Kg=2.2 lbs
1 mile- 1.6km
1 knot =1 nm/hr
1 nm = 1.852km

Parts of the Piston- piston, piston rod, piston ring.
Propeller- A mechanical device for propelling a vessel consist of revolving shaft
Ballasting- pumps sea water into empty storage tanks when the ship is very light.

ENGINEERING MATERIALS

Metals and Non-metals

METALS-are having high thermal and electrical conductivity

2 Groups
Ferrous Metals-are having IRON as common element. High Permeability
Ex. Cast Iron, Steel, Silicon Steel

Non Ferrous-Having low permeability.. Support the formation of magnetic field.
Ex. Silver, Copper, Gold, Aluminum

NON-METALS-are non crystalline in nature. Bad conductor of heat and electricity
Ex. Rubber, Plastic, Leathers

Metals and Alloys
METALS-are polycrystalline bodies which have number of differentially oriented fine crystals
ALLOYS-Composition two or more metal or metal and non-metal (ex. Steel, brass, bronze)
CERAMIC MATERIALS-are nonmetallic solids made of inorganic compounds(oxide, nitrides, silicides) (ex.glass,cement,silica)
ORGANIC MATERIALS- having carbon as a common element.(ex. Plastic, synthetic rubbers)



MECHANICAL PROPERTIES

Hardness-resist wear, abrasion and cutting
Plasticity-it is plastic if it is very soft and easily deformed and does not return to original shape after deformin
Brittleness-permits no permanent deformation before breaking(break instantly)
Ductility-ability to deform under tensile stress
Malleability-ability to deform under compressive stress
Toughness- a material will break under a sudden impact.

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