DieselShip's Online Content Library

Q1. i) Draw the stress Vs strain curve showing the different phases of change that occurs when an elastic material is subjected to load. (5)

ii) What is plastic deformation of material and how it is caused? Explain yield stress & how strain hardening is caused? Where is this phenomenon successfully used? (6)

iii) Explain fatigue and how fatigue failure occurs? suggest means in practice as to how fatigue failure can we avoided. (5)

Q2. i) Which elements present in the heavy fuel oil, (fossil fuel) used in marine diesel engines, results in the formation of SOX, H2SO4 and CO2 upon combustion. Discuss their effects on the environment, post combustion. (10)

ii) What is understood by 'NOX' & how it is produced? State the temperature at which it is formed. (6)

Q1. i) Sketch and describe using a Fuel oil treatment before injection. (10)

ii) What is the purpose of centrifuging fuel and how gravity disc is selected? (3)

iii) Why homogenisers and fine filters are used downstream? (3)

Q4. Write short notes on following with respect to lubricating oils.

a) Base oil (4)

b) Additive (4)

c) Contaminants (4)

d) Sampling & testing (4)

Q5. i) What is the stern tube bearing and why it is provided? (4)

ii) Name the bearing material used & how same lubricated & cooled? (3)

iii) For 'oil lubricated' stern tubes,

how oil is prevented from flowing out? Explain sealing arrangement with line sketch & material used. (6)

iv) Name the type of oil used for lubrication. (3)

Q6. i) Sketch and describe the 'drive mechanism' of a centrifuge? (10)

ii) State the component in the horizontal and vertical drives (3)

iii) state the purpose of providing: (3)

a) clutch mechanism

b) worm & wormwheel

c) bowl assembly

Q9. Reverse osmosis is the contemporary alternative for shipboard production of drinking

a) Describe using simple diagrams where necessary, the principle of:-

i) Osmosis (3)

ii) Reverse osmosis (3)

b) Sketch a line diagram showing a ‘single pass system’ for producing fresh from seawater. (4)

i) Describe such a system. (4)

ii) State the safety features that may be incorporated into the plant. (2)

Q7. With reference to electric arc welding:

a) Draw a labeled sectional sketch of a satisfactory butt weld. (5)

b) Briefly define the following defects that may occur and how they may have been caused (6)

i) Under cut

ii) Splatter

iii) Inclusion

iv) Blow hole

v) Incomplete root penetration

vi) Lack of fusion

c) Why is alternating current generally more popular then direct current for metal arc welding? (5)

Q4. Sketch and describe an Independent two-stage air compressor. Draw a set of typical Indicator diagrams and insert the various pressures and temperatures. Indicate the effect of a leaking H.P. suction valve and excessive H.P. clearance volume. (16)