DieselShip's Online Content Library

Q7. Discuss the causes of corrosion and the means by which corrosion of the following may be limited by manufacturers and ship’s personnel respectively:

A. Internal and External surfaces of auxiliary steam lines;

B. External surfaces of auxiliary boilers;

C. Water boxes of seawater coolers and condensers;

D. Main sea water inlet pipes.

Q6. Briefly describe the tests made on a piece of metal to determine its suitability for use in engineering. Explain clearly what is meant by any four of the following metallurgical terms:

(a) Work hardening,

(b) Cased hardening,

(c) Annealing,

(d) Normalising,

(e) Nitriding.

Q5. A. With reference to fatigue of engineering components explain the influence of stress level and cyclical frequency on expected operating life. (6)

B. Explain the influence of material defects on the safe operating life of an engineering component. (5)

C. State the factors which influence the possibility of fatigue cracking of a bed-plate transverse girder and explain how the risk of such cracking can be minimized. (5)

Q8. A. Explain the action of EACH of the following metallurgical mechanism:

(i) Creep;          (ii) Brinelling;   (iii) Fretting;     (iv) Fretting corrosion;

B .State, with reasons, where EACH of the mechanisms in occur in ship propulsion System.

Q7. With reference to steels used in shipbuilding and marine engineering:

(a) describe EACH of the following types of failure;

(i) Brittle failure;

(ii) Ductile failure.

(b) Explain the term ductile to brittle transition stating the factor that determines ductile to brittle transition.

(c) Describe a test to determine the value of brittle fracture of a specimen test piece.

Q7. Compare the destructive testing done on engineering materials with non-destructive testing done on engineering components. Briefly describe one destructive test and two non-destructive tests to illustrate your answer

Q2. (a) Materials used for hull and machinery are subject to stress and strain in service.

Define EACH of the following:

(i) types of stress;              (ii) types of strain

(b) Describe the tests that may be carried out on steel to be used for ships side plating.(5)

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.

Q8. Explain why a material may fracture when stressed below its yield point. Give examples of components which might fracture in this way if suitable precautions are not taken. Explain how such fractures can be avoided with reference to the materials chosen, careful design and workmanship.

Q3. A. Explain the causes of the formation of mill scale on steel plate. Describe the preparation necessary before the application of conventional paints to the underwater surface of the hull; C. Describe a coating scheme for the underwater hull using conventional paints.

Q2.a) Define fatigue and fracture and specify the conditions under which it occurs.

b) Describe the different fracture modes and the mechanism of crack propagation in different fracture modes.

Q1. Discuss the causes of vibration and noise in main gearing and describe detrimental effects on machinery and operating personnel. How would you detect the source(s) of this vibration and how might it be reduced to tolerable limits?