DieselShip's Online Content Library

Q1. What is the meaning of “de-rating” of machinery?

a) Explain the principles behind de-rating a ship propulsion engine as a retro fit. And the benefits. (8)

b) Can a de-rated engine be run at full power? If yes, under what conditions? (8)

Q6. (a) Explain fatigue cracking, stating its causes and propagation.

(b) Explain, how poor maintenance and engine overload may contribute to the risk of fatigue cracking of cylinder head holding studs.

Q1. Crankcase oil mist detectors have undergone a lot of changes in recent years. Compare the modern types with multiple sensor units with the traditional single sensor type, where sampling was done sequentially. What is meant be addressable sensors.

Q2. 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

Q2. With reference to LNG diesel engine installations:

(a)Describe, with the aid of a sketch, a Gas Valve Unit, explaining its purpose and indicating where it is located in the gas train.

(b) Explain why ventilation and inert gas systems must be installed with the engine fuel gas system.

(c) State why pilot injection must be provided when burning fuel gas, explaining how a pilot injection system works

Q3. (a) Sketch a typical power indicator card for a slow speed marine diesel engine.

(b) Explain how the card may be used to assess the power developed in the Cylinder.

Q2. With reference to behaviour of fabricated bed plates and frames in services:

A. Identify various forces imposed simultaneously upon them;

B. Explain how engine structure withstands these forces;

C. State how these forces are transferred to ship’s structure

Q3. What is slow steaming & how it’s achieved without engine modification? Enumerate various operational issues with slow steaming. How such operational issues can be dealt with?

Q8. a) To improve the power-to-weight ratio of an engine, it is necessary to increase the mep. Discuss the importance of turbocharger compression ratio in this regard. Why has it become necessary to introduce two-stage turbocharging?

b) With reference to turbochargers with variable turbine area, explain

i)Which area is varied

ii)Why is it varied

iii)How is it varied.