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Q9: With reference to sleeved keyless propeller assemblies: A. (i) State, with reasons, the metals used in the manufacture of the sleeve and tail end shaft; (ii)State the type and thickness of material used to bond the sleeve to the propeller boss. B. When removing the propeller from the tail end shaft, state why the following procedures are not recommended: (i) Application of push off force by means of wedges or jacks and draw off force by strong back; (ii) Expansion of propeller boss by concentrated local heating with gas torches. C.  State the correct procedure for the removal of the propeller from tail end shaft

Q1. A. Explain the ideal design requirements of a ships propeller; B. briefly describe the propeller maintenance that should be carried out to prevent the fuel being wasted.

Q8. Explain why, in spite of accurate alignment under static conditions use of flexible couplings and copious supply of lubricant, main reduction gearing in still subject to pitting, scuffing and other tooth damage; B. Discuss the significance of viscosity in relation to the function of marine turbine oils as used in main propulsion installations, stating how the viscosity is controlled and what could cause it to change in service.

Q2. A. Sketch and describe a Pilgrim Nut for securing a propeller to the screw shaft; B. Describe how this device is used to loosen the propeller on the shaft when removal or inspection becomes necessary; C. Give four reasons why this method is considered to be superior to all other methods.

Q3. A. Sketch a transmission shaft coupling which enables the propeller shaft to be withdrawn outward.

(a) describe the coupling and the method fitting and dismantling;

(b) state how the grip of the coupling can be checked when fitted;

(c) State what safety precaution should be taken when dismantling the coupling.

Q9. Misalignment of the Main shafting between engine and propeller causes bearing overloads and shaft stress.

a) State the difficulties associated with checking the shaft alignment and the reasons why results are unreliable due to external factors.

b) State the reasons for misalignment

c) Explain with a simple sketch how a bearing load is assessed.

d) Explain how uneven loading could be rectified

e) Why wear down in main bearings is critical to the condition of the condition of the crankshaft and propeller system.

Q6. With reference to keyless propellers explain:

a) Why keys and keyways have been eliminated

b) How angular slip is avoided

c) Why mounting upon and removal of a propeller shaft requires a different technique than that employed for propeller with keys.

d) State with reasons why use of wedges and jacks are not advisable when removing the propeller from its shaft

Q3. With reference to propeller shaft alignment:

a) state the objectives of a satisfactory alignment

b) state the conditions that must be met to achieve satisfactory alignment

c) explain what is meant by fair curve alignment.

d)Define "sag and gap" in shaft alignment calculation.

Q7. Sketch an arrangement of propeller shaft and stern in which the tube is filled with oil and

a) Describe the attention it requires at sea

b) Suggest a method of repair when the rubbing surfaces Of the Oil seal get estate the defects that you would look for when the shaft is withdrawn in the dry-dock.

Q8. Discuss some of the factors which effect the shaft alignment of ships propulsion shafting. Suggest the most effective methods adopted for achieving the best possible alignment? (16)

Q8. With reference to main propulsion shaft systems:

(a) describe a method of hydraulic jacking to check bearing loads; (8)

(b) sketch the Bearing Load versus Shift Lift Dial Gauge Reading graph obtained by the method described in part (a), annotating the graph and how the characteristic of bearing load is obtained. (8)

Q5. a) Describe how propeller shaft/stern bearing clearance is measured.

b) Identify with reasons the major factors which substantially determine the range of permissible clearance.

c) State with reasons what parts of propeller shafts should receive particularly close inspection upon withdrawal of such shafts for survey.

d) State why some propeller shafts require less frequent inspection than others.