The favourite question of this Section of the examination paper, and attempted by about 67 per cent. of the candidates. Some very good solutions were given, but arithmetical errors were frequent. The "centre of buoyancy was not clearly defined by a large number of candidates, and some stated that the "centre of buoyancy" was the "centre of gravity" of the immersed portion of the ship, instead of "centre of gravity" of the volume of displacement.

Q. 14. What are the fundamental conditions which must be fulfilled, in order that a vessel may float freely, and at rest, in still water? Attempted by about 25 per cent. of the candidates, and was very well answered. A few stated as one condition that "centre of gravity" and "centre of buoyancy" must be in the same vertical "plane," instead of same vertical "line."

Q. 15. Define the terms "draught" and "trim."

Describe the method adopted for marking the draught marks correctly on a ship, and state where, and how they are fixed on the hull. Select any type of ship with which you are acquainted, naming the type chosen.

Attempted by about 21 per cent. of the candidates, and the answers were disappointing. There were only a small number of fair papers, the others were very poor.

STAGE 2.

Results 1st Class, 79; 2nd Class, 175; Failed, 76; Total, 330.

PRACTICAL SHIPBUILDING.

Q. 21. Sketch the lower portion of the midship section of any vessel, extending from the middle line, to the margin-plate in a Mercantile vessel, or to the 3rd longitudinal in a War vessel; showing inner and outer bottom plating, framing, &c. Indicate which parts are continuous and which intercostal; give scantlings and state sizes and spacing of rivets.

A favourite question, attempted by about 59 per cent. of the candidates, and generally very good answers were given.

Q. 22. Why are stealers worked in the shell plating?

Show by sketches how a stealer is worked, in either an inner or outer strake of plating, and show the disposition of the rivets. Attempted by about 34 per cent. of the candidates, and generally satisfactory answers were given, except that the chasing of the plates in the vicinity of the lap was only referred to by a few.

Q. 23. Show a good shift of butts of the flat keel and gutter plates, with reference to those of the verticai keel, and angles connecting them; also with reference to the butts of the garboard strakes of plating.

Only 6 per cent. of the candidates attempted this question, About onehalf of the answers were fairly well done, but the others were poor and incomplete.

Q. 24. Where, how, and for what reasons are zinc protectors fitted to the hulls of ships?

What precautions are taken to prevent deterioration of the underwater portion of the shell plating?

What portions of the internal parts of the hull of a steel veszel are most liable to corrosion on service?

A favourite question, attempted by about 51 per cent. of the candidates, and very satisfactory answers were generally given, although the first part of the question was seldom fully answered,

Q. 25. Show, by rough sketches, the general arrangement of the equipment necessary around the building slip for a large vessel; also show the arrangement of staging neccessary. Give a rough plan, without details, of the means of conveying the materials from the machine shops to the ship.

Attempted by about 32 per cent. of the candidates, and some very good answers were given; the others were generally satisfactory.

Q. 26. How would you take account of, prepare, get in place and secure a shell plate in wake of the boss where a shaft leaves the ship? Attempted by about 17 per cent. of the candidates; about one-third of the answers were good, but the others were poor. The question was described too much in general terms without explaining in detail; the sighting battens for setting cradle and adjusting the plate were only mentioned by a comparatively small number.

Q. 27. How are the entrances into double-bottom compartments, or ballast tanks, made watertight?

Show how such compartments may be sounded, and what provision is made for the escape of air, when the compartments are being filled with water.

A popular question, attempted by about 61 per cent. of the candidates, and generally very well answered. Some did not make a very clear sketch of the watertight manhole cover.

Q. 28. Sketch a rudder for any type of vessel acquainted, naming the type selected. disposition of rivets, pintles and bolts.

with which you are State the sizes and

Explain. (1) How such a rudder may be readily unshipped.
(2) How water is prevented from finding its way
through the rudder trunk into the ship.

(3) How the rudder is prevented from turning
beyond a certain angle.

(4) What means are taken to prevent the rudder from being accidentally unshipped at sea.

Attempted by about 36 per cent. of the candidates, and generally well answered; some very good answers were given. A few did not show the centre line of pintles and rudder head in the same straight line.

LAYING OFF.

Q. 29. What lines are usually employed for fairing the form of a vessel ? Where are each specially valuable as tests of fairness? What is a diagonal? How would you proceed to obtain the form of a diagonal, in the sheer and half breadth plans?

The favourite question of this section of the examination paper, about 52 per cent. of the candidates attempting it. About three-fourths of the answers were satisfactory, with the exception that a diagonal was only correctly described by a small number; the remainder of the answers were poor,

Q. 30, What is a ribband? Where are they placed, and how are they secured? Describe, with sketches, how you would proceed to obtain the necessary information to prepare a ribband for the ship, and state what distinguishing marks, etc., are placed upon

it,

Attempted by about 38 per cent. of the candidates. The answers were generally incomplete, and only about one-third of those who attempted it obtained fair marks,

Q. 31. What information is given to the frame bender for bevelling the frames? State the position on the frames at which bevellings are given, and explain clearly how the information is obtained. In what form is this information given to the workman? Illustrate your answer by taking three or four frames nearest the sternpost.

Attempted by 17 per cent. of the candidates, and fabout one-third of the answers were fairly satisfactory, the others were poor. Very few candidates correctly illustrated the answer by taking three or four frames nearest the stern post.

DRAWING.

Q. 32. What does the given sketch represent. It is drawn on a scale of "to 1 foot; draw it neatly in pencil on a scale of 1" to 1 foot, and show the number of rivets you consider necessary in the frame and bracket angle bars, &c.

Six candidates did not attempt this compulsory question. The drawing was generally well done, but some of the candidates appeared not to have any ship curves with them at the examination. A number of candidates did not describe what the sketch represented, and in some cases the rivets were drawn by hand instead of by compasses, and the spacing of the rivets was stated but not shewn to scale.

CALCULATIONS.

Q. 33. State the rule known as "Simpson's first rule.”

The semi-ordinates of the deck boundary of a ship, commencing forward, are :---0, 14′6, 23′0, 28′1, 310, 322, 325, 32'4, 319, 305, 247, 193, and 0 feet respectively. The length of the deck is 384 feet. Find the area of the whole deck, and the longitudinal position of its centre of gravity.

Twelve candidates did not attempt this compulsory question. The answers were generally satisfactory, but arithmetical errors were far too frequent. A number of the candidates, in stating Simpson's first rule, omitted to state that the ordinates must be an odd number. Many used a wrong common interval, obtained by dividing the length of the deck by the number of ordinates, instead of the correct interval obtained by dividing by the number of spaces. Some candidates stated the rule incorrectly, but worked the question correctly.

Q. 34. Describe, in detail, how you would proceed to obtain the curve of displacement of a vessel, having given the curve of tons per inch immersion. Show by rough sketches the usual shapes of these curves, and also show how to deduce from the curve of tons per inch immersion, a curve representing the heights of the centre of buoyancy above the keel.

Attempted by 15 per cent. of the candidates. About one-third of the answers were satisfactory; the remainder were poor. Many explained how to deduce the heights of the "centre of buoyancy" above the keel from the displacement curve instead of from the curve of "tons per inch." Q. 35. A middle line keelson, 400' long, is made up of mild steel plates 36" deep. The plates of the middle half of the length are 14" thick, and the plates at the ends are 13" thick. The keelson continuous angles-two at the bottom and two at the top-are 61" × 41" × 10". Calculate the weight of the keelson including rivets, &c.

20

Attempted by 27 per cent. of the candidates. About one-half of the answers were good, but the others were very poor. A frequent mistake in dealing with this question was to mix up feet and inches, and in many cases the work was laid out in a slovenly manner, resulting in muddle.

ft

Q. 36. Define the terms "centre of buoyancy," "centre of gravity," "centre of flotation," ""metacentre" and "metacentric height.'

The centre of gravity of a ship is 12' from the bottom of keel. In this condition her displacement is 2,500 tons. She is then loaded in the following manner :

95 tons are added 8' 6" above the bottom of keel.

Find the new position of the centre of gravity from the bottom of the keel.

Attempted by about 35 per cent. of the candidates, and generally well answered. Several candidates stated that the "metacentre" is the point of intersection of the line joining the "centre of buoyancy" and centre of gravity" in the upright condition, with the line joining those points when the vessel is slightly inclined. The "metacentric height was often described as the distance between the "centre of buoyancy" and the "metacentre."

STAGE 3.

Results 1st Class, 27; 2nd Class, 65; Failed, 98; Total, 190.

There was a decrease of about 5 per cent. in the number of candidates who sat at the examination in this stage, as compared with last year.

The standard of the answers was not so good as last year, and a large number of papers had to be cancelled owing chiefly to candidates' not complying with the instructions printed at the head of the examination questions.

A conspicuous and disappointing feature of the worked papers in this stage was: (1) the failure of 37 candidates (nearly 20 per cent. of the total) to attempt either of the questions set in the "Laying Off" Section of the examination paper, and (2) the generally poor answers of those who did attempt one or both of those questions. Injsome cases candidates wrote on their worked papers-"No laying off ever learned," and other similar remarks. This is very unsatisfactory; so much of the work of the preparation of materials is carried out on the mould loft floor, that it is absolutely essential candidates should possess a knowledge of the general problems in laying off. The two questions set this year merely involved finding the intersection of a plane at right angles to one of the planes of projection, with the lines of a ship or a cylindrical surface, and all the candidates in this stage should be sufficiently well acquainted with the theory of laying off to be able to obtain at least some marks.

It appears that, generally, more attention should be given to the printed syllabus which is now prepared in much detail and is considered sufficiently comprehensive.

The practical questions were, on the whole, well answered, and it is satisfactory to note that there was an improvement in the quality of the sketches, and sketching is much to be encouraged.

The compulsory question, No. 52, which requires candidates to place their own lines for calculating purposes, and measuring the ordinates by means of a scale, was generally well answered, but 4 candidates made no attempt to answer the question.

A few candidates attempted all the questions set in the "Calculations" section of the paper although the instructions clearly stated that candidates must not attempt more than three questions, including No. 52, from that section. Arithmetical errors were far too common, and many of the answers contained an unfortunate mixing up of units, feet and inches, or Pounds and tons, in the same formula.

9291.

F

PRACTICAL SHIPBUILDING.

Q. 41. Describe, with sketches, giving scantlings, how a large machinery or cargo hatchway is framed out in a deck, and point out the means adopted to compensate for the loss of transverse strength due to cutting the beams.

A popular question, about 120 candidates attempting it, and about 25 per cent. of the answers were very good. The sketches were, on the whole, well done, and in several cases they were very clear indeed. Where difficulty was experienced, it was generally only in the second part of the question.

Q. 42. A crew space of a vessel is approximately 50' x 28'. Show by sketches, giving details and approximate dimensions of fittings, a good arrangement for messing and sleeping as many as possible of the crew, allowing for a suitable width of gangway. Attempted by about 67 candidates. It was generally well answered, except as regards the details that were asked for.

Q. 43. Describe, with sketches, how the cast steel shaft brackets of a twin screw ship are secured in place. What tests are made before these brackets are accepted as fit for the service intended?

This was also a favourite question, about 114 candidates attempting it, and about 25 per cent. of the answers were very good. The sketches were generally fairly well drawn, but the tests stated for such castings were, in many cases, insufficient for the purpose of determining the fitness of the brackets for service.

Q. 44. Sketch roughly the midship section, and briefly describe the construction of a large lifeboat forming part of the equipment of a ship. Indicate the materials used and the fastenings.

Attempted by 36 candidates. About six of the answers were satisfactory, but the remainder were generally poor and incomplete. Many candidates gave an outline of a lifeboat such as is used for rescue purposes round the

coast.

Q. 45. Describe generally, with sketches, any system of refrigeration used on board a steamer arranged for carrying cargoes of frozen meat, showing how the pipes conveying the freezing medium are arranged, and state what arrangements are made for observing and regulating the temperature from outside the chamber. What insulating material is used in the holds, and how is it arranged? Give detail sketches.

About 34 candidates attempted this question, and about nine of the answers were very good, but the remainder only answered parts of the question. One or two of the candidates stated that liquid air is used as the freezing medium; another stated that a brine preparation of water mixed with a certain proportion of calcium carbide is used. The arrangements for observing and regulating the temperature of the chamber were generally omitted.

Q. 46. Roughly sketch, in plan, a good arrangement of engine bearers for a large twin-screw steamer, naming the type of vessel selected. Give sections of the bearers at a crank pit, and at a transverse bearer.

Only 30 candidates attempted this question, but it was generally well answered. There were about 8 very good answers.

Q. 47. Sketch and describe, in detail, how cabins are built. Describe briefly how cabins are ventilated, with hot or cold air, in any modern type of vessel with which you are acquainted, naming the type selected.

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