MAR. 5.]

THE NEW ZEALAND GAZETTE.

FIRST CLASS.
First Paper.

The questions are not to be copied. The answers should be written on form
Exn. 30. Extra paper will be supplied if required.
Do not deface or make any marks whatever on this paper.

1. What is meant by the term "volumetric efficiency" as applied
   to the internal-combustion engine? Sketch a light spring
   indicator diagram for a four-stroke cycle Diesel engine, and
   show how the volumetric efficiency may be determined
   approximately by its means.
2. Describe, with sketches, a three-stage blast air-compressor for a
   Diesel engine, and explain why stage compression is adopted.
   Indicate the course of the air through the compressor, and
   state approximately the maximum pressure and temperature
   of the air at each stage.
3. Explain what is meant by the "flash-point" of an oil, and state
   approximately the flash-point of Diesel oil as determined (a) by
   the open test; (b) by the closed test. Describe an apparatus
   for determining the flash-point of an oil, and explain how it
   is manipulated.
4. Describe any reversing arrangement for a marine Diesel engine
   with which you are familiar. Explain why it is sometimes
   found difficult to reverse the engines, and mention what provision is usually made to facilitate starting when manoeuvring.
5. State the precautions to be taken in regard to the cooling of the
   pistons and cylinders of Diesel engines (a) prior to starting;
   (b) while running; (c) immediately after stopping. Discuss
   the relative merits of sea-water and fresh-water cooling-systems, and state, approximately, the maximum outlet temperature of the piston and cylinder cooling water respectively
   in each case. What relation does the temperature of the
   piston-cooling water bear to that of the cylinder-cooling water ?
6. Give a brief description of the construction of an auxiliary steam-boiler usually found on board motor-vessels. State what
   attention the boiler requires when working, and what care is
   necessary for its maintenance in satisfactory condition.

Second Paper.

7. Give a description of any defects in the main or auxiliary machinery
   of a motor-ship which have come under your notice. State
   the causes of these defects and the methods of repair adopted,
   and suggest preventive measures.
8. Describe, with sketches, the construction of the main engine-seating of a modern motor-ship, and indicate in what respects,
   if any, it differs from that of a steamship. Show clearly the
   method of securing the engines to the ship's structure.
9. State, in the case of a six-cylinder four-stroke cycle Diesel engine,
   the timing of the opening and closing (a) of the starting-valves ; (b) of the fuel-valves ; (c) of the inlet-valves ; (d) of
   the exhaust valves. Explain why it is necessary to provide
   clearance between the cam rollers and the idle portions of the
   cams, and mention the effect of the overlapping of the inlet
   and exhaust cams.
10. Describe in detail a reliable method of testing the alignment of a
    multi-cylinder Diesel-engine crank-shaft. Explain how the
    main bearings of engines of the above type are usually constructed, and how they are removed and replaced with the
    shaft in place.
11. Give a description of any starting arrangement for a multi-cylinder
    Diesel engine with which you are familiar. Explain the action
    of the starting - valves, mentioning how and when they are
    brought out of action. State what governs the duration of
    opening of these valves.
12. What means are usually adopted to safeguard the windings, &c.,
    of compound-wound dynamos when run in parallel? Mention
    the dangers incident to running machines of the above type in
    parallel, and state which type of dynamo is most suitable for
    this duty, and why.