Test example 6
Class 1
1. Describe how alignment of shafting between engine and propeller shaft is checked with the vessel afloat. State how alignment is corrected in the case of appreciable hull deflection.
2. (a) Make a simplified sketch of the operating mechanism for a controllable pitch propeller.
(b) Describe briefly how pitch is altered in accordance with telemotor signal.
(c) State what ‘fail safe’ feature is incorporated into the logic of the mechanism.
3. Identify the defects to which propeller shafts are commonly susceptible. Explain how propeller shafts are surveyed in order to detect these defects.
4. (a) Sketch a ‘muff’ (flangeless or sleeve) coupling for connecting adjacent lengths of main transmission shafting.
(b) Describe the manner in which the coupling is mounted on and transmits torque between the adjacent lengths of shafts.
(c) State how astern thrust is accommodated by the coupling.