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Q9.  A report on the analysis of the main crosshead engine crankcase lubricating oil indicates the following contaminants or property changes. In EACH of the following cases give reasons for the possible causes of the contamination or property change, explaining how the actual cause would be detected; .

A. The presence of fresh water; B. White metal fragments; C. Reduced alkalinity reserve; D. Reduced anti oxidation reserve.

Q1. (A) Explain how wear on bearing surfaces is effected by each of the following factors:

(i) Dissimilarity of materials in the contact surfaces

(ii) Relative speed of sliding between the surfaces

(iii) Roughness of the surfaces

(iv) incompatibility of lubricant and bearing material.

(b) Describe how each effect may be identified during inspection, Suggest corrective action at either operational or maintenance stages.

Q2. a) Explain the term fuel ignition quality and indicate how a fuel’s chemical structure  Influences its value
b) State, with reasons, the possible consequences of operating an engine on a fuel with a lower ignition quality than that for which it is timed.
c) (i) Explain how an engine might be adjusted to burn fuel of different ignition quality.
(ii) State what checks can be carried out in order to determine that the engine is operating correctly.

Q3. Describe the developments that have taken place in the design of bearings of slow speed marine diesel engines, including geometry and material, focusing on the reasons for such changes.

Q4. Periodical Lubricating Oil Analysis, its correct interpretation and corrective measures are of critical significance for the maintenance of marine machineries. With reference to the modern analysis techniques employed for the condition of L.O, discuss the following:

A) Elemental (Spectrometric) Analysis

B) Fourier Transform Infrared (FTIR) Spectroscopy

C) Particle Count

D) Base Number Vs Acid Number

Q1. Describe following types of lubrication system with suitable examples

(a) Hydrodynamic Lubrication

(b) Hydrostatic lubrication

(c) Elasto-hydrodynamic lubrication

(d) Boundary lubrication

Q9. Describe the developments that have taken place in the design of bearings of slow speed marine diesel engines, focusing on the reasons for such changes. (16)

Q3. With respect to the properties of fuel oil, explain the significance of the following terms.

(a) Calculated Carbon Aromaticity Inbox (CCAI).

(b) Open flash point and Closed flash point.

(c) The importance of Sodium to Vanadium Ratio.

(d) Octane Number.

Q5. a) Outline the problems associated with effective lubrication of the liner and piston assembly of a large slow speed engine. (6)

b) What are the causes of cloverleafing and micro seizure. (5)

c) Explain the composition of a cylinder oil suitable for an engine operating on residual fuel. (5)

Q8. Explain how the ingress of sea water is prevented in an oil lubricated stern bearing system. Should the system fail, describe the corrective action possible whilst the vessel is afloat. State why two stern bearing oil header tanks are fitted in some instances?

Q3. With reference to the burning of heavy residual fuel in the main engine:

a) State with reasons FOUR modifications which need to be made as compared with the same engine burning distillate fuels.

b) State with reasons SIX properties you would require seeing in the specification for residual fuel indicating the effect EACH of these properties might have with respect to the storage and burning of the fuel.

Q6. With reference to the fuel standards ISO-8217-2017 discuss the amendments made as compared to its previous edition. Explain the significance of the following:

(a) Pour point, cloud point and cold filter plugging point.

(b) Cat fines

(c) Fatty Acid methyl Easter

(d) Dissolved H2S in fuel.