APPENDIX

QUESTIONS.

CHAPTER I.

1. Distinguish between the terms "structural" and "local" strains as applied to a ship. Enumerate a number of "local" strains. Have any of these local strains been sufficiently great in your experience to cause damage?

2. State the reasons for the superior efficiency of a I beam of steel to a solid rectangular beam of wood.

3. How may a ship be compared to a beam, and what parts of the structure are most efficient from this point of view?

4. How are the longitudinal strains on a ship's structure made the subject of calculation?

5. Why is the structure at the keel and at the upper deck considerably stronger in a long cruiser than in a battle-ship of the same total displacement?

6. Why is it that the boat deck and the topside plating adjacent are not made an integral part of the structure in a ship having a boat deck?

7. To what special sort of strain are the flat portions of a ship forward specially liable? Why do you consider that this straining action is less in evidence in war-ships than in merchant steamers ?

8. Why is it possible to build a steel or iron ship considerably lighter than a ship of the same size built of wood?

9. Why must special attention be devoted to the strength of the upper deck and structure adjacent in a vessel of large proportion of length to depth? From this point of view, show that the most recent method of protection of large cruisers is more likely to prove economical as regards weight of hull structure than that adopted in, say, the cruisers of the Edgar class.

10. Suppose one had a vessel 300 ft. long, the structure of which had proved sufficiently strong, and a vessel of the same depth, but 360 ft. long were required. Discuss generally what portions of the structure would have to be strengthened to ensure the new vessel being sufficiently strong.

11. Indicate how the inspection and maintenance of a ship influences the design of the structure.

CHAPTER II.

1. State the qualities of "mild steel" that make it a suitable material for shipbuilding purposes.

2. Compare in tabular form the tests laid down for "mild steel,” “rivet ""cast steel."

steel,"

3. What tests are necessary in a steel casting beside those relating to the strength and ductility of the material? Why are such tests of great importance for castings of steel?

4. Compare the tests for "mild steel" and those for the special steel used in cruisers and destroyers.

5. It is laid down that holes in high-tensile steel must be drilled, and not punched. Why is this?

6. Describe the process of "pickling" steel plates. What trouble would you expect to arise in a ship's structure from the steel of which the "mill scale" had not been removed before painting?

7. Draw out to a large scale the section of a zed bar, a tee bulb, an angle bulb, and a I bar. State places in your present ship in which these sections are used.

8. A flange is frequently used on the edge of a plate instead of an angle bar for connection purposes. What advantage is thereby secured? State places in your present ship where this is done.

9. Describe the most ordinary form of rivet used in ship work, and show how such a rivet is used for the outer bottom plating where the outside surface must be flush.

10. What is meant by the pitch of rivets? State the amount of this pitch for rivets 7-in. diameter where the work has to be watertight. What pitch would be used for 3-in. rivets for internal work not watertight?

Ans. 4 to 4 in.; 51 to 6 in.

11. When your ship is next in dry dock, examine the "lap" caulking and the "butt" caulking of the outer bottom plating.

12. State the various advantages that result from ordering plating by the weight required per square foot rather than by thickness.

13. Taking the area of the outer bottom plating of a vessel as 30,000 square ft., estimate the saving of weight, if the steel plating is ordered 20 lbs. per square ft. instead of in. thick. What further saving would

be possible if the manufacturer sends in all the plating down to the limit allowed, viz. 5 per cent. under? Ans. 5'4 tons; 134 tons.

14. If the area of the outer bottom plating (specified of 15 lbs.) is 20,000 square ft., what variation of weight is possible, in view of the latitude allowed to the manufacturer ? Ans. About 13 tons.

15. What is annealing? What is the effect of annealing on a plate which has had a large number of holes punched in it?

CHAPTER III.

1. Distinguish between "bracket frame" and "solid plate frame." Where are these frames used in a large armoured ship?

2. Describe generally the construction adopted in battle-ships below armour within the limits of the double bottom.

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3. What is a floor-plate"? Sketch and describe the framing of a battle-ship before and abaft the double bottom.

4. State the advantages of having a double bottom to a ship. Why is it not possible to provide a double bottom in the smaller ships of the Royal Navy? Discuss the question of fitting a wing bulkhead below the armour deck in a large cruiser.

5. Why is the "transverse system of construction more suited to the ends of a large ship than the "longitudinal" system?

6. Draw out a table with rough sketches showing the supporting frames for 4-in., 6-in., 9-in. armour. Why is a rigid support of great importance behind armour?

7. Draw in outline midship section, describe and compare the main features of (1) Admiral class, (2) Royal Sovereign, (3) Majestic, (4) King Edward VII.

8. Draw in outline midship section, describe and compare the main features of the first class cruisers (1) Edgar, (2) Diadem, (3) Cressy, (4) Monmouth.

9. Draw in outline midship section, and compare the main features of two second class cruisers. Show how the intended service has had a distinct influence on the design.

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10. Draw in outline the midship section of a sloop," and point out what provision is made in such a vessel for protective purposes.

11. State in general terms the distinction between a battle-ship and a first class cruiser. Compare H.M.S. Triumph with H.M.S. Duncan and H.M.S. Cressy, and state in what category you consider she should be placed.

12. Discuss the question of working zed bars for the framing of ships instead of two angles riveted back to back from the point of view of (i.) economy of weight, (ii.) saving of cost.

13. Discuss the importance of avoiding discontinuity of strength in a ship's structure.

14. Name typical vessels of the Royal Navy which are sheathed with wood and copper. Why have all the sloops and most of the second class cruisers built in recent years been sheathed ?

15. In going through the double bottom of a vessel it will be noticed that the non-watertight longitudinals have no lightening holes in certain frame Trace the reasons for this.

spaces.

16. Taking the length of the double bottom of a battle-ship as 250 ft., and the frame spacing 4 ft., make an estimate of the saving of weight if an oval manhole 23 in. x 15 in. is cut in every frame space in the non-watertight longitudinals. Ans. 5 to 6 tons.

17. What advantages beside saving of weight are obtained by cutting lightening holes in a longitudinal girder?

18. State places in your present ship where you have noticed holes cut for lightening purposes. Do you consider any weakness has resulted from

the removal of this material?

19. What is a middle-line keelson? When this is intercostal, and the floor

plate is continuous from side to side, how is proper continuity of longitudinal strength obtained?

CHAPTER IV.

1. Draw out the sections of the beams used in your present ship for the various decks and platforms. State the spacing of the beams amidships and at the ends.

2. Under what circumstances are zed bars likely to be advantageous for beams? Why do you consider it would have been inadvisable to form the beams to the decks of your ship of zed bars?

3. Why is the connection of beams to frames of great importance? Draw out two such connections as fitted in your present ship.

4. What is a carling? State places in your ship where carlings are fitted.

5. Why should the upper deck of a vessel be given a round up while the platform deck is worked level?

6. Why would a log of timber wedged up between-decks be inefficient as a pillar from a structural point of view?

7. Name places in your ship where the pillars have had to be made "portable."

8. In sailing ships of the mercantile marine in which only one bulkhead (the collision bulkhead) is fitted, it is laid down in "Lloyd's Rules" that the beam arms have to be three times the depth of the beam. Discuss the reasons for this, bearing in mind the ordinary practice in ships of the Royal Navy.

9. If the upper deck of your ship is completely plated, trace the bolt fastenings to the planks of the wood deck. See also where these bolts are placed to take the butts. If the deck is not completely plated, see how the butts of the planks are fastened.

10. Why are pillars always made hollow in vessels of the Royal Navy? 11. Notice in your ship the arrangement of butts of "sheer strake,” "stringer plate," and the structure adjacent. See how a good shift of butts is obtained. Why is this of great importance?

12. What do you consider the advantages and disadvantages of corticine as a covering for decks in place of wood? How is this corticine secured? 13. Describe the operation of "caulking" as applied (a) to steel plating, (b) to a wood deck. In both cases state what preparations are necessary before the caulking is started. What essential quality is caulking intended to secure?

CHAPTER V.

1. What special advantages attach to the use of steel instead of iron for the skin plating of a vessel ?

2. Trace in Fig. 46 how the strength of the structure is made as uniform as possible, no special frame space being a special place of weakness, but a good shift of the butts being obtained.

3. What is the "raised and sunken" system of working the outer bottom plating? What is the function of the "liner "?

4. Sketch a 66

lightened liner." Does the lightening in any way injure the strength of the structure?

5. State places where the outer bottom plating of a large ship is doubled. For what purpose is this done in each case?

6. Why is the transverse section of a ship in way of a watertight bulkhead a line of weakness? Show how this weakness is compensated for.

7. Sketch the form of bulkhead liner adopted in your present ship.

8. State the requirements necessary in a watertight manhole to a doublebottom compartment. Draw out to a large scale the plug fitted in the cover, and state its uses.

9. Make a tabular statement giving the thicknesses of keel, outer bottom plating, and sheer strake in (a) a battle-ship, (b) a second class cruiser, (c) a third class cruiser, (d) a sloop, (e) a destroyer.

10. What is a "liner"? What purpose does it serve? Would there be any objections to making such a liner of iron instead of steel if desired on the score of cheapness?

CHAPTER VI.

1. What is a "collision" bulkhead? Why is this bulkhead of great importance?

2. How far is the collision bulkhead from the forward perpendicular in your ship? How does this compare with the distance required for merchant ships, built to the rules of "Lloyd's Register," viz. one-twentieth the length?

3. Why do you think the rules of the Registration Societies specify the minimum distance of the collision bulkhead abaft the stem ?

4. State the special advantages attendant on the provision of a watertight bulkhead between the engine-rooms.

5. For what reason is the stiffening adopted for the main bulkheads of a large ship of so strong a character? Why can the bulkheads at the ends of the machinery space be safely built with considerably less stiffening than those between the boiler-rooms?

6. How are compartments of a ship tested for watertightness while building? What does this testing ensure besides watertightness?

7. Write out the instructions regarding the tests required for watertight compartments of ships in commission. (See Admiralty Circular, S. 32111/1903, January 29, 1904.)

8. What is a cofferdam" bulkhead? Is one fitted in your present ship? If so, state the means of access to the space between it and the collision bulkhead.

9. When a magazine is placed next to a boiler-room it is usual to provide an air space between to prevent the magazine becoming heated. Is this the case in your present ship? If so, how is access obtained to the space? Why is such access necessary?

10. Trace the means of escape under protection fitted in your ship from the submerged torpedo-rooms. Why is such escape necessary?