Chapter IV: Part 4

With respect to auxiliary machinery, the Scotts invariably fit a separate centrifugal pump for circulating the water through the condenser for all classes of engines, excepting only those for the ordinary tramp steamer. The air, bilge, and sanitary pumps are usually worked from the main engine by levers. The feed pumps are generally independent. Frequently, especially in yachts, all the pumps are entirely independent of the main engines. The Scotts in some cases make all auxiliary machinery for their own engines: such as centrifugal pumps, fans, feed-heaters, auxiliary condensers, duplex feed and ballast pumps, etc.

Many varieties and types of boilers have been made. The old practice of having two or three rings in the length of the shell in ordinary cylindrical boilers has long since given place to one plate in the length. The boiler ends are seldom made in more than two plates; up to diameters of 11 ft. only one plate is used. The number of riveted seams is thereby reduced to a minimum, and the liability of the boiler to leak is minimised. The Scotts also have a system of forced draught for supplying either cold or heated air to the furnaces, which is fitted largely to their ships, and gives every satisfaction. Large installations of Belleville and Yarrow water-tube boilers for working under forced draught have also been made and fitted in H.M. ships, but they need no description here. A large installation for burning oil fuel has recently been completed and applied by the firm to the Babcock and Wilcox water-tube, and the cylindrical, boilers of H.M.S. _Argyll_.

FOOTNOTES:

[68] From _Lloyds' Register_ we classify, according to speed, the numbers of British and Foreign, and of Oversea and Channel, Steamers, of over 16 knots.

---------------------+----------+----------++----------+----------
Speed. | British. | Foreign. || Oversea. | Channel.
---------------------+----------+----------++----------+----------
Over 20 knots | 42 | 26 || 17 | 51
19 to 20 knots | 23 | 11 || 7 | 27
18 " 19 " | 38 | 14 || 15 | 37
17 " 18 " | 53 | 49 || 67 | 35
16 " 17 " | 70 | 56 || 77 | 49
+----------+----------++----------+----------
| 226 | 156 || 183 | 199
---------------------+----------+----------++----------+----------

Efficiency: Design: Administration.

Having reviewed the history of the firm, and dealt briefly with the results obtained by some of the modern steamers constructed by them, we propose now to describe the Works in order to indicate the measures adopted to secure efficiency in design and construction of all types of ships and machinery. Organisation and administration are as important factors towards this end as the mechanical methods and appliances adopted, and it may be well, therefore, to deal first with these.

The firm have been responsible for the design of almost every merchant ship constructed by them. Success has been rendered more certain by the possession of carefully-collated records, the product of an organised system of working up all data, of tackling new problems, of making calculations regarding any scientific question, and of studying contemporaneous work as described in the technical press and in papers read at technical institutions. This continuous investigation produces a wealth of suggestion, which enables the chiefs of the respective departments to determine how far practice may be improved; and thus there is steady progress not only in design but in constructional methods. A well-selected technical library, from which the staff can borrow books, also contributes to the same end.

Admiralty and merchant work is initiated in separate drawing-offices. The "Printed Instructions to Draughtsmen" throws light on the general principles which influence design, and one or two quotations may be made:--"Every machine or structure is designed with a certain object in view; therefore, in designing, keep that object always to the front. Go straight to the point, and let the object be attained in as simple a manner as possible. Avoid all curves and indirect lines, except those conceived to give uniform strength or stiffness, or required for some definite purpose. There should be a reason for the contour and shape of every detail. It should be remembered that designs made in this way, requiring least material for the work to be done, usually look best. Besides keeping the object clearly to the front, it is necessary in designing to remember that certain facilities must be attended to for moulding, machining, and erecting. It is also necessary to keep in view the circumstances in which the structure or machine is to be used. Every little detail should be definitely attended to on the drawings, and not left to the judgment of the men in the shops; remember that it is usually the unexpected which happens, and that even the want of a split pin may cause a breakdown. In making drawings or sketches for ordering material or for the shops, assume that those who have to interpret the instructions have no knowledge of, or information concerning, the work in question, except what is contained in the drawing or order you are making out. This will ensure that all information issuing from the drawing-office is complete, and that no work is done in the shops without drawing-office instructions."

The draughtsman, in designing work, must so arrange details as to fully utilise, as far as is compatible with progress, the special machine tools available, the system of gauges, templates, and jigs extensively applied in the shops, and existing patterns. Bonuses are paid for improvements in design whereby economy may be effected in machine operations, etc.

There is a large estimating department, where records of costs, rates, wages, etc., are of the most complete description. The card system adopted is admirably suited for enabling references to be made at any time as to the cost of units in any contract. Here also it is possible, by the simple process of comparison, to effectually check the economy of design and manufacture, without which a high premium is placed against efficiency.

The staff in these departments is largely recruited from the shops, and thus there is an incentive to the willing apprentice to excel. The great majority of the vacancies in the technical staff are filled by apprentices who have spent three and a-half years in the shops, and who are chosen as a result of examination and of a satisfactory record in the shops. Financial facilities are afforded to boys and to progressive workmen to attend special classes, not only in Greenock but in Glasgow. Competitions are instituted at intervals to encourage expertness in some branch of work--for instance, in the use of the slide-rule, etc. Thus in many ways the growth of an active _esprit de corps_ is encouraged, apart altogether from the influence which the historical and present-day success of the firm engenders.

The same broad policy is pursued in the shops. Payment by merit to the tradesman is adopted as far as possible. In the engine works the bonus system--first adopted in 1902--is extensively applied. The arrangement is satisfactory from the point of view of tradesman, employer, and client.

Long experience has enabled the firm to set equitable standard times for many operations, and there was from the beginning the guarantee that this standard would not be altered unless entirely new machines were introduced to greatly influence the rate of production. Now if a workman requires the full time, or more than the time set as a standard for a job, he is still paid his full-time wage as under the old conditions: but should he complete the work in less than the standard time, his rate of wage per hour is increased in direct proportion to the saving in time; the shorter the time taken, the greater the rate of bonus. The bonuses earned range as a rule from 20 to 30 per cent. over the time-rate wage. To quote actual cases, a workman who saves 26 hours on a job for which the standard time is 134 hours, increases his wage for the fortnight by 14s., while the money saved to the employer is only 2s. 9d. He who saves 30 per cent. on the time adds 21s. to his fortnight's wage.

Such reduction in the time taken is not attained at the expense of efficiency; the premium job is carefully inspected, and unless it is of the highest standard the bonus is forfeited; so that the workman is continuously careful to avoid any risk which will result in the loss of the reward for his extra work. The reduction in time taken is, in a large measure, due to the exercise of foresight and ingenuity on the part of the workman. He is ever on the alert to ensure that he will not be kept waiting for material to enable work to progress. The machine-man makes certain that before one unit is out of his machine the casting, forging, or bar for the next is alongside. This is further facilitated by a man in each shop whose only duty is to see that there is a supply of work for every tool. Encouragement is always accorded to those who suggest modifications to increase the output from any machine. Again, in the erecting of engines, considerable economy has been attained, owing to similar foresight being exercised to ensure that each unit is machined before it is wanted by the erector.

To the employer also there is gain in the increased production, from a given number of machines and men, for a constant establishment expenditure--rent, rates, taxes, etc. While the wage paid to the men is increased, there is a reduction in the cost of production, which of itself encourages capital expenditure on improved methods and appliances. Concurrently with the adoption of the bonus system there has been a great increase in the cutting speed of tools, which has also augmented the rate of production. This "speeding-up" is partly due to the fitting of new machines, to the substitution of forged steel machine-cut gear for cast spur-wheels, to the strengthening of lathe headstocks, to wider belts, to the application of reversible motors to some machines, and to quicker return speeds.

Some indication may be given of the increased economy resulting from the bonus system and from the "speeding-up" of tools, as compared with the former system, with slower speeds and piece-work rates. A typical job, which had formerly occupied eighty hours, was, after experience, given a standard time of sixty hours. When first carried out under the bonus system the time actually taken was forty-five hours, the labour cost being reduced from £2 13s. 4d. at piece-work rate to £1 17s. 6d. under the bonus system, while the wage of the worker was increased by 2d. per hour. Subsequently, a repeat of this job was machined by the same man, who, having confidence that the time allowed would not be reduced, finished the work in thirty-nine hours, saving twenty-one hours on the standard time, reducing the cost to £1 15s. 0d., and increasing his rate of pay by 2.8d. per hour. Other comparisons might be given to show the advantage over the piece-work. In successive fortnights after the introduction of the system, the percentage of time saved on the time taken on piece-work in one department steadily advanced from 16 per cent. to 47 per cent., and ultimately the pay of the men per hour was increased 75 per cent., while the saving to the employer was 50 per cent.

The client profits, as the contract price is reduced without any diminution in the satisfactory character of the work done; indeed it is probable that this is improved because of the special inspection to ascertain if the bonus has been conscientiously earned. A lower contract price, therefore, is possible; and this places the firm, both directly and indirectly, in a better position in competition in shipbuilding. There is more work obtainable, more constant employment for the workmen, with the additional inducement of higher wages to capable and diligent men.

The Shipbuilding Yard.

Covering an area of 40 acres, the Works have ten berths for the construction of ships of all sizes, with departments for producing all the accessories and machinery--engine and boiler works, steam-turbine factory, foundries, brass, copper, and sheet-iron shops, saw-mill and extensive wood-working department--and these give employment to four thousand workmen. The equipment has been greatly extended and modernised during the past few years. The building of the China Steam Navigation Company's steamer _Fengtien_ in nineteen weeks, from the laying of the keel to the trials, is one of several instances of rapid construction which might be enumerated.

The plans of ships prepared in the designing department and drawing offices, to which reference has been made in the previous Chapter, are passed to the moulding loft, where the work of construction is commenced. This loft is situated in a substantial four-storey building, accommodating practically all the wood-finishing departments. Each floor has an area of 12,500 square feet; the ground and first floors are given up to the joiners and cabinet-makers, with their numerous machine tools, while the top floor is at present utilised for storing completed joiner work, etc. The moulding loft monopolises the third floor, and as the length is 240 ft. and the width 52 ft., there is ample space, as is shown on the engraving in Plate XL., facing page 94, for laying down full size deck-plating, stringers, margin plates, deck girders, etc., so that moulds or templates may be prepared for the iron workers. Armour-plates for warship belts, barbettes, and casemates are similarly prepared in template, to assist the makers to form them to the required curvature and size.

The ironworkers' department is extensive and important. When the material is delivered into the yard, it is discharged from the railway wagons by a 5-ton electric overhead travelling high-speed crane, which stacks the plates and bars in such a way that any piece can be readily removed by the same crane for conveyance to the furnaces.

There are six furnaces suitable for heating shell plates of the largest size, and angles and bars for frames, etc., up to 60 ft. in length. Adjacent to the furnaces are the screeve boards and the frame-bending blocks. The channel, bulb angle, or Z bars, used so extensively now for framing in large ships, are bevelled as they pass from the furnace to the bending blocks. This is done in a special machine made by Messrs. Davis and Primrose, Leith, and illustrated on Plate XLI., adjoining this page. The bars, as delivered from the rolling mills, have flanges at an angle of 90 deg., which is not suitable for taking the skin plating of ships. One angle has therefore to be altered, so that while the inner flange may lie at right angles to the keel-plate, that to the outside will fit closely to the shell plating throughout the entire length of the frame from keel to shear stroke, which may be 50 ft. or 60 ft.

As the bar passes through the machine, the web is carried on an ordinary flat roller, while bevelling rolls, set to the desired angle, work on each side of one of the flanges to give it the desired set. There are several of these machines in use, and they run on rails laid across the front of the furnace, so that the angles, Z sections, or channels may be bevelled while passing out of the furnace on to the bending blocks. The manipulation of the plates from the furnace is by means of steam and electric winches.

Formerly, the turning of the frames to the required curvature against the pins on the bending blocks was carried out by hand. To suit the heavier scantlings of the larger ships of the present day, a portable hydraulic machine is now utilised. It is fixed at its base by pins, which fit into the ordinary holes in the blocks, and hydraulic pressure is supplied through a flexible pipe to work the ram-head against the angles, forcing them to take the desired form. The machine is a great labour economiser, as it ensures work on the heaviest of bulb angles being carried out in the minimum of time, and therefore at top heat.

The bars are usually cut to length by a guillotine, but it was considered that this tended to twist the metal, and perhaps unduly fatigue it; and as a consequence the firm have fitted John's shearing and notching machine, as constructed by Messrs. Henry Pels and Co., of Berlin. This new machine is illustrated on Plate XLI., adjoining page 95. The tool is shown in the act of cutting through a channel section. The cutting tool is seen immediately in front of the operator, and is actuated by gearing accommodated within the standards of the machine. When the cutting tool is brought down on the angle or beam to be sheared, and the shaft at the rear started, the rotation of an eccentric actuated by the shaft causes the point of the tool to slide idly a short distance to-and-fro on the bar. The hand lever on the right hand side of the machine is depressed, forcing the tool downwards, and the continued rotation of the eccentric causes the tool to pierce through the bar with a downward and inward motion. Where there is a deep web with flanges, the beam is reversed on the anvil, to enable the other flange to be cut. The cutting of any bar in this machine is a matter of only a few seconds.

Of the platers' shed, where the plates, angles, bulbs, bars, etc., are machined, two views are given on Plates XLII. and XLIII., facing pages 96 and 98 respectively. It may be said generally that the machines are designed to deal with plates up to 50 ft. in length, and with angles up to 60 ft. in length, and of corresponding sections. It follows that the straightening and bending rolls, edge-planers, and punching and shearing machines, are of great power. It is scarcely necessary to make detailed references to all of the tools for these and other purposes.

All the tools are electrically driven. The plate-flattening rolls, which have 15 and 20 horse-power reversible motors, take plates 8 ft. wide, and the rolls are from 21-1/2 in. to 19 in. in diameter. The bending rolls are driven by a 20 horse-power motor. The plate-edge planers, shown to the left in the view, Plate XLII., facing page 96, are operated by 16 horse-power motors, and the plate is held on the table by means of hydraulic rams as well as screw-jacks. For drilling and countersinking plates there are several modern tools, each actuated by an independent electric motor. One of these is a three-standard drill, to deal with plates of the largest size. The spindles have a rise and fall of 10 in., and are fitted with self-acting, as well as hand, feed, and with the usual rack arrangement for the traverse of the head. Several radial countersinking machines, with 11-ft. jibs and spindles 2-1/2 in. in diameter, are driven by 10 horse-power motors. There are many heavy punching and shearing machines, nearly all of them having 42-in. gaps, so that they can punch holes at any part of the widest plates. As a rule, they are arranged to punch 1-1/2-in. holes through 1-1/2-in. plates at the rate of thirty holes per minute. The shears are of corresponding power.

For dealing with angles and bars there are several interesting tools, in addition to shears and punches. Some of the shears cut 8-in. by 4-in. angles, and are driven by 10 horse-power motors. There are channel-angle shearing machines, taking work 16 in. by 6 in., and operated by hydraulic pressure. These machines are made with revolving gear to suit almost any angle of flange.

There is also an hydraulic stamping press for bending angles and tees to form knee-bars and other stiffening pieces, the cylinders being 14 in. in diameter, working at a pressure of 800 lb. per square inch, with a stroke of 18 in. The machine, which has been constructed by Sir William Arrol and Company, Limited, consists of an hydraulic cylinder mounted horizontally on a massive table. On the ram-head there are former blocks, while on the table in front there are corresponding dies. The bar is placed on the table between the blocks and dies, and as these are forced together by hydraulic pressure, the bar between them is squeezed into the exact shape required. Not only is the operation expeditiously executed, but there is no uncertainty. The whole of the metal within the bar is retained inside the knee, which becomes thicker and broader, materially adding to its strength. As the moulds or dies can be made to suit any form, the machine can be utilised in the preparation of various details of structures, provided they are designed with a view to their production by aid of dies. The great economy resulting from the use of special machines is only realised when the designing staff remember that they must be kept employed.

A specially powerful tool is provided for bending channel irons and beams, and for drilling horizontal holes in them. Hydraulic manhole-punching and flanging machines are employed, each having a ram of 27 in. in diameter, and capable of punching a hole 42 in. by 16 in. through a plate 3/4 in. thick. There are provided dies for forming flanges 4 ft. 6 in. deep in the widest of plates.

The modern practice of joggling and of scarfing the laps and edges of plates is applied in many instances, and special hydraulic tools are provided to carry out this work. The firm were also early in adopting the practice of joggling frames, deck beams, etc. The frames and beams are joggled when cold, to suit each alternate inner strake of plating, in a special design of hydraulic press, of which there are several in the works. This tool, illustrated on Plate XLI., adjoining page 95, carries dies on the ram-head and on the anvil, to form between them the obverse and reverse sides of the dent or joggle desired. Movable centre-pieces on the ram-head and anvil are traversed in all directions by screw thread to suit the position and width of the joggled part, and a gauge shows variations of 0.1 in. in the position of the joggled part of the frame. A 2 ft. length of angle can be joggled at each stroke. The machines are by Messrs. Hugh Smith and Co., Limited, Glasgow.

The same machine joggles the lap or edge of a shell, inner bottom, or deckplate in a similar way. The whole length of the frame or plate can thus be worked in a very short time. A powerful jib crane, of 16 ft. radius, assists materially in the rapidity of the work turned out by these tools. The only slips required are at the ends of the vessel, where the bevel of the frames precludes the use of joggling. A special electrically-driven hammer is used for forming these taper slips.

The angles, etc., to form the frames are assembled at the head of the building-berth, and when lying on skids are riveted to form the double bottom, frames and margin plates. Hydraulic riveters are used wherever possible. There are about a score of these at work in the shipbuilding yard, with cylinders from 8 in. to 10-1/2 in. in diameter, a stroke of 7-1/2 in., and a gap of 55 in., so that heavy work can be done. Some of them are specially designed for keel work, for closing rivets in beams, and for difficult parts.

The frames thus riveted are conveyed down the berth by a simple and ingenious cableway, known in the Works as the "switchback," from its resemblance to the well-known amusement railway. A derrick-post stands at the head of the berth adjacent to the skids on which the frames are riveted. The cable stretches from a small derrick at the foot of the shipbuilding berth over a pulley at the top of the large derrick-post, and thence, through a similar block at its base, to an electric winch. The frame or unit of the ship's structure is suspended on a running block on the cable, which is then made taut, partly by the working of the winch and partly by the large derrick post being inclined backwards. The running block with its load travels down the taut cable by gravity, under the guidance of the squad of fitters. The gradient of the cableway is only sufficient to enable the load to move slowly to its position in the shipbuilding berth.

The double-bottom frames and margin plates are united with the keel-plate, and subsequently there are successively worked into the structure the tank top plates, side frames, the skin plates, beams, bulk-heads, and other units, portable hydraulic punches and riveters being largely used. Pneumatic tools are also extensively employed for boring, drilling, riveting, chipping, caulking, etc. There are from 130 to 140 of these tools in use on vessels in course of construction.

There are ten building berths ranging in length up to 700 ft.; but slight alterations would enable the firm to build vessels of still greater size. Several of these are shown on the engraving on Plate XXXVII., facing page 88. The launching ground is probably the finest in the river, the channel being here of great depth and very wide, as is shown on the engraving opposite. Indeed, ordinary merchant vessels with full lines are launched without any check chains; the fine-ended ships--mail steamers and cruisers--are, as a precautionary measure, checked by drags in the usual way. The engraving on Plate XXXVIII., facing page 90, shows the launch of H.M.S. _Argyll_.

The ships launched are completed in the fitting-out dock, constructed about two years ago, and illustrated on Plate XLIV. The engraving shows H.M.S. _Argyll_ under the big jib-crane. This dock has a length of 560 ft. and a width of 172 ft., and opens directly into the channel of the Clyde. The depth of water is never less than 28 ft., so that warships are afloat at all states of the tide. A prominent feature in the view is the crane, which was supplied by Messrs. George Russell and Co., Limited, of Motherwell, and lifts 120 tons at a radius of 70 ft. It is carried on concrete foundations and piers, which rise 20 ft. above the level of the quay. In addition to the pier for carrying the mast of the crane, there are similar supports for each of the back legs through which the crane is anchored.

One advantage of the derrick type is that the crane may be placed close to the edge of the quay; in this case the centre is only 7 ft. from the front of the wharf, so that the full load of 120 tons can be dealt with at an effective outreach of 63 ft. from the quay. The maximum radius of the heavy purchase with a load of over 60 tons is 90 ft., and of the light purchase gear, with a load of 10 tons, 98 ft. The minimum radius of the crane is 25 ft. There are four sets of gear: for lifting heavy loads, for raising light weights, for derricking the jib, and for slewing; a separate controller of the enclosed tramway type is provided for each. The main hoisting and derricking motors are of 50 horse-power, and the others of 35 horse-power. The speed of hoisting 120 tons is 5 ft. per minute, while a 10-ton load is raised at the rate of 40 ft. per minute. Automatic brakes are fitted for the slewing motion, and powerful hand-brakes for the hoisting and derricking gears. All motions are controlled by one man in the steelhouse fixed to the mast of the crane 56 ft. above the quay level.

There is on the opposite wharf of the dock a 20-ton travelling electric crane, and throughout the Works there are many portable and hydraulic cranes, in addition to the hydraulic and other cranes commanding the machine tools.

Reference may here be made to the Company's graving dock, illustrated on Plate XLV., adjoining page 101. The length is 360 ft., and it is largely used for docking ships for repair, as well as for cleaning ships preparatory to trial. Our view shows a torpedo-boat destroyer in the dock. The pumps for the emptying of the dock are electrically driven.

We may return now to our narrative of the construction of a ship, and deal with the supplementary departments, including those of joiners, smiths, plumbers, sheet-iron, and other workers.

Wood-work forms a large and important item in most of Scotts' ships, as many of them are for passenger service. We illustrate on Plate XLVI. one of the saw-mills. It is self-contained, having its own power plant, including a compound engine, having cylinders 15-1/4 in. and 27-1/2 in. in diameter by 44-in. stroke. There are four vertical saw frames, the largest having a 36-in. frame, six rollers, and two bogies to take in the heaviest logs. In addition, there are circular saws, ranging up to 6 ft. in diameter, a swing cross-cut saw, special planing, moulding, and turning machines to do heavy work, and saw-sharpeners, grindstones, punching machines and anvils to carry out all repairs and fettling of the blades, etc. There are also large steam-heated drying stoves, and a timber-drying yard of about three acres in extent. The overhead travelling cranes range up to 5 tons capacity, and the rails on which they run are extended on columns across the yard. The saw-mill is the largest and best-equipped in the district, and does the sawing and planing of timber for three of the largest shipbuilding yards, as well as the general work for two other firms.

The joiners' and cabinet-makers' shop, as we have already indicated, occupies two floors of a building 240 ft. long and 52 ft. wide; while the fourth floor is utilised for the French polishing work, as well as for storing the completed wood-work until the vessel is ready to receive it. Provision is also made in the same building for the model-making department, in which replicas of nearly all ships are produced, and, being works of art, because of their completeness, accuracy, and beauty, have earned high awards at many Exhibitions.

In the joiners' shops, illustrated by two engravings on Plate XLVII., adjoining this page, there is a complete equipment of wood-working machines for sawing, turning, planing, moulding, sand-papering, mortising, boring, tenoning, dovetailing, dowelling and joining. These are electrically driven, and are grouped at three places in the length of the shop on each floor, with benches around them, so that the joiners do not require to carry their jobs any distance in order to have them machined. There is also in use in connection with the department a portable electric circular saw, which is specially useful for carpenters and joiners, etc., on board the ship in the dock. An electric deck-planer, of the lawnmower form, has proved serviceable in reducing enormously the most laborious task experienced by carpenters and joiners.

There are two large smithies convenient to the shipbuilding berths, and in both cases the finishing department adjoins. In one case there are fifty-four fires and eight hammers; in the other, forty fires, with five hammers, ranging up to 15 cwt. The fires are operated by mechanical blowers, and the smoke and waste gases are carried off by overhead ventilating pipes. Extensive work is carried out by the smiths. Die-stamping is largely adopted in connection with the making of eye-plates, cleats, stanchions, clips, etc. In each finishing shop there are band saws, radial and other drills, screwing machines, and grindstones. Smiths' stores are arranged above the finishing shops.

The plumbers' shop is fitted with a special machine for bending pipes when cold, as well as screwing and tapping machines, drills, saws, grinders, and fires.

The sheet-iron department is equally well equipped, having straightening rolls, shearing, punching, chipping, drilling, and other tools, with various hammers; and here work is done in connection with ventilating and other light ironwork.

In view of the warship contracts undertaken, the mechanics' shop, for work peculiar to the ship as distinct from the propeller machinery, etc., is extensive. The four lathes here range up to 27 ft. in length over all, with a 14-in. headstock and a 22-ft. bed. There is a useful shaping machine, a fair-sized planer, and several drills, all adequate for the work required, which is remarkable more, perhaps, for its great variety than for size.

All the machinery in the yard, and in several departments in the engine and boiler works, is run from one central station, of which two views are given on Plate XLVIII., opposite. The electric generators occupy one side of the power station, and the air compressors and hydraulic pumps the other. Steam at 200 lb. pressure is supplied by one marine cylindrical, and four Babcock and Wilcox water-tube, boilers, with superheater, coal conveyors, and mechanical stokers.

There are three electric generating sets, with a total capacity of 1200 kilowatts, the voltage being 240. They are illustrated on Plate XLVIII., facing this page. The engines are of the high-speed, enclosed, forced lubrication, condensing type. The current is distributed from a switchboard in the power station by overhead mains, with three-way distributing panels in the various departments. The motors, of which there are about 130 in the shipbuilding department alone, are of the two- and four-pole type, partly or entirely enclosed, and mostly of 10 to 20 electric horse-power. Arc lamps are used for lighting, but the shops and offices are also illumined by 16 and 32 candle-power incandescent lamps. Plugs are arranged at various points throughout the yard for portable lights, and for connecting mains for lighting the various ships while being completed in the docks.

Hydraulic power at 800 lb. pressure is generated by two high-pressure pumps, with steam cylinders 15 in. in diameter, and rams 4 in. in diameter. There are separate accumulators for each. The pressure pipes are led underground throughout the Works to the various hydraulic tools already referred to.

There are two air compressors for supplying power for the pneumatic tools. The combined capacity is 1800 cubic feet of free air per minute. Each has two steam cylinders 6 in. in diameter, working respectively high- and low-pressure air cylinders 15-1/4 in. and 21-1/4 in. in diameter, the stroke being 18 in. The hydraulic pumps and the air compressors are illustrated on Plate XLVIII., facing page 104.

As we have already stated, part of the power generated in this station is utilised at the engine works, to which we may now turn our attention.

The Engine and Boiler Works.

Rapidity of construction has been characteristic of the engine and boiler works of the Scotts to at least as great an extent as in the shipbuilding yard. Several instances might be noted, beginning with six blockade-runners, built in a very short period, in 1864, and fitted with engines to give a speed of 12 knots at sea and 13-1/2 knots on trial. A recent and striking instance is the construction of boilers and engines for twenty of the passenger steamers built for traffic on the Thames, to the order of the London County Council, and described on pages 83 and 84, _ante_. The contract for this work was signed towards the end of November, 1904, and work was commenced about the beginning of December. The various parts of the engines were being machined and finished during the month of January and the beginning of February, 1905; and all of the twenty sets of engines and boilers were completed by the end of May. Another noteworthy case is the construction of the machinery for the steamship _Fengtien_, described on page 80, _ante_. Work was commenced on the machinery in the middle of January, and finished about the end of April. The machinery was fitted in the ship and ready for the trials on the 29th May. The total time taken from the beginning of work was well under five months.[69]

The pattern shop, where all work originates, is fitted with the usual pattern-making machinery, including a core-making machine.

The iron foundry, which was begun in 1790,[70] and around which the large engineering establishment has since been raised step by step, continues to do sound work. There are four cupolas, of a combined capacity of about 20 tons, and cylinders up to 120 in. in diameter are cast. These facts suggest the satisfactory character of the equipment.

The brass foundry is an equally important department, where first-class work is done. There are fifty-two crucible pots in use, varying in size up to 150 lb., and of a collective capacity of about 2 tons; also an air furnace capable of producing at one heat 12 tons of metal, for such heavy castings as are required for preparing shaft liners, large sea chests for naval ships, etc. The strength of Admiralty gun metal made in this foundry is up to 18 tons per square inch, with 30 per cent. of elongation in a 2-in. length. The foundry is served by an electrically-operated jib crane.

In the forge and smiths' shops a large amount of detail work is done, in units ranging up to 3 tons in weight. The hammers vary up to 15 cwt. power. A considerable amount of die-stamping is done in connection with auxiliary engine forgings, etc. All paddle-wheels are made in this department. The blast for the fires is got from an electrically-driven fan.

The machine shop, which was one of the first constructed with a completely glazed roof, occupies a site on a steep slope, one side being formed by a heavy retaining wall, as shown in the engraving on Plate XLIX., facing page 106. At the level of the top of the wall, which is 25 ft. high, there is the light machine shop, while at the end of the bay and over the annexe situated to the left of the engraving, is the brass-finishing shop. There is a 2-ton hoist between the erecting-shop floor and the galleries, so that no inconvenience, so far as transport is concerned, is involved by this arrangement.

Originally a stream ran down the hill and over the site on which the Works are located, and its waters have for many years been utilised as a source of power. A special 24-in. inward-flow turbine works in the conduit which conveys the water across the site, and this turbine develops continuously 80 horse-power. This serves to drive some of the machines in the boiler works. The turbine runs in parallel with a compound vertical engine, which drives the shafts actuating the groups of small machines in the engine shop. Many of the larger tools, however, are electrically-driven by separate motors, the current being transmitted from the central station already described.

The engravings on Plates XXXIX. and XLIX., facing pages 92 and 106 respectively, illustrate the main machine shop, which has a width of 60 ft., and, with the adjoining bay, accommodates some of the finest marine engineering tools made. Perhaps the best indication of their efficiency is the fact that three weeks suffice for the machining of the parts of a complete set of engines to develop 2000 horse-power. The shops are traversed by five overhead electric cranes, ranging up to 40 tons lifting capacity.

The leading dimensions and the principal work done by the more important tools afford an idea of the extent of the equipment. There are several planing and slotting machines, one of which is shown in the engraving on Plate L., facing this page. There are two combined machines, to plane 21 ft. and to slot 18 ft., used in connection with the condensers, cylinders, large bearing frames and sole-plates of engines, while two other smaller tools are devoted to finishing the castings for bed-plates and columns. For machining eccentric-rod ends, etc., there is a 24-in. slotter with a circular table. There are two high-speed planers with two tool-boxes on the cross-slide, which take in pieces 10 ft. by 5 ft. by 5 ft., and one to take work 12 ft. by 3 ft. by 3 ft.

In the driving of some of the heavier tools very good results have been attained by the application of a reversible motor, which in one case has dispensed with four belts, a pair of bevel wheels, and two countershafts, reducing enormously the frictional waste, and enabling higher speeds and quicker return strokes to be attained.[71]

For drilling work there are several large tools. Recently there has just been fitted a multiple machine which, while primarily intended for drilling the tube-holes in drums and water-pockets of Yarrow water-tube boilers, is also utilised in connection with ordinary machine work. This tool, of which an engraving is given on Plate L., facing page 108, was manufactured by Messrs. Campbells and Hunter, Limited, Leeds. It has a massive cross-slide carrying four saddles, movable by a powerful screw, driven by spur-gearing and friction-clutch, controlled from one of the saddles. The steel spindles are balanced, and have a special self-acting, variable, rack-feed motion, as well as a quick vertical motion by hand for rapidly adjusting the drill through the jig. Each spindle can be operated independently. The table has a sliding motion, directed by two straight screws coupled to the cross shaft and vertical shaft, and is carried by a straight bed with three bearing surfaces. This machine, which weighs 20 tons, is driven by a 30 brake-horse-power electric motor.

There are two vertical boring mills used for cylinder work, one being capable of boring up to 120 in. in diameter, and the other to 94 in. in diameter. A combined boring and facing machine, with a table 4 ft. square, is usefully employed on propeller bosses, valve-chests, small cylinders, and built-up bed-plates, machine bearings, etc.

The installation of high-speed lathes is specially noteworthy. In one, the face-plate can take in 12 ft. in diameter, and, as the length of bed is 30 ft., it is useful for large surfacing work, as well as for turning crankshafts of the larger sizes. There are two 12-in. double-geared lathes for surfacing and screw cutting. These are self-acting, and the lengths of bed are 19 ft. and 12 ft. respectively. For turning piston and connecting rods, two screw-cutting lathes of 16-1/4-in. centres are in use, the length of the bed being 22-1/2 ft. These have each a triple-gear headstock, and a chuck 48 in. in diameter; with rack motion and slide-rest feeds. A 20-in. centre lathe, with a bed 28 ft. 6 in. long, is fitted with two saddles and four slide-rests for shaft liners, etc. Amongst others, there is a 27-in. centre lathe for shafting, the bed being 36 ft. long.

One of the lathes is illustrated on Plate LI., adjoining page 109. This is a 48-in. surfacing and boring lathe, by Messrs. John Lang and Sons, Limited, Johnstone. The two new features introduced are the variable speed drive and automatic speed-changing mechanism. The headstocks can be used for single or triple gear, and are so arranged that, even when running at the greatest speed, there is a reduction by gearing. With this arrangement the lathes have greater power when turning small diameters than when the belt is used driving direct to the main spindle. The spindles, which are hollow, with hexagonal turrets, are of crucible cast steel, and run in gun-metal bearings. By means of the speed-changing mechanism, the cutting speed of the tool is kept practically constant when surfacing. This means that any surface can be finished off in about one-half of the time taken by a lathe having the ordinary step-cone drive, where the workman will not change the position of the belt while surfacing. The self-acting feed-motions are positive.

Milling is adopted in many instances in preference to planing or slotting, and this is especially so in connection with valve quadrants, columns, faces, etc. For the first-named there is a large vertical miller, and for the latter a horizontal tool with a vertical milling apparatus. For grinding bolts, etc., a machine having a separate head for grinding taps is used, the emery wheel being 18 in. in diameter and 1-1/2 in. broad.

A shop, now in course of construction, is to be specially laid out for the manufacture of turbine machinery of the greatest power. It is to be 285 ft. long, with a span of 60 ft. Heavy lifts will be taken by a 100-ton overhead crane, and ordinary work will be handled by a 40-ton electric crane. The heavy machine tools, while specially chosen for turbine work, are also adaptable for use in the manufacture of the heaviest reciprocating machinery. The principal tools are large lathes suitable for turbine rotors and crank-shafts; vertical boring machines which may be utilised for work on cylinders as well as on turbine casings; and a heavy planer, 10 ft. by 10 ft. by 25 ft. stroke. The necessary small machine tools for turbine work will be put down in this department, whence also some of the large tools will be removed from the existing shops, so that it will be fully equipped for the purpose intended.

The brass-finishing shop, which is illustrated on Plate LII., facing page 110, serves both for ship and engine work. It has only recently been laid out anew. The machines, according to the latest practice, are arranged down each side of the shop, and the benches occupy the centre. Each alternate bench is utilised for the material to be operated upon, so that the working bench is not littered in a confused way, as is too often the case. There are representative types of the best makes of automatic tools, turret lathes, brass-finishers' lathes, and grinding machines with specially large discs.

A considerable amount of work is done to limit gauge in all the shops which we have described. This practice has been considerably developed recently, and a specially equipped department has been organised, where gauges, templates, and cutting tools are made. This department is illustrated on Plate LIII., facing this page. A word may first be said as to the significance of this new department. Where three or four ships have engines of the same type, a set of jigs and templates for the most important parts are at once made, so that a unit from an engine in one ship may be fitted to an engine in another. This simplifies the ordering of new parts, and greatly reduces the number of spare items which have to be kept in store by the owners, in order that repairs or refits may be effected at short notice.

For some time the Scotts have adopted this system, so that it was a simple matter to enforce it in connection with the machinery of the twenty Thames Steamers, and in recent naval work, where the practice is being applied in an extended form. In the recent Admiralty work every part of an engine is made interchangeable and identical with the corresponding parts of other engines for the same type of ship, although built in different parts of the country; and this fact alone will indicate the extent and intricacy as well as the care and degree of accuracy necessary. This standardisation to ensure interchangeability has reached its highest exemplification in the case of the machinery for the armoured cruiser _Defence_, of 27,000 indicated horse-power, to be completed in twenty-one months from the placing of the order by the Admiralty.

Then, as regards the tool-making and fettling--the other branch of work carried out in the tool room--it has been recognised that, to make the cutting tools efficient, it is necessary to utilise the most suitable steel for the tools working on various metals and alloys; and the selection of the tool steel for each metal has been systematised by the careful collation of data of actual work. In the manufacture of the tools special appliances are used and will be referred to presently. The workmen are encouraged to use only tools in sound condition. Each machine-man in the shops has ten checks, and may borrow from the store a corresponding number of tools, but these must be returned as soon as possible for overhaul and re-grinding. The bonus system further induces the men to ensure that their tools are in good condition.

The tool department is separate from the main structure, and in it all jigs, templates, and gauges, as well as tools, are constructed. Standard gauges, as well as limit gauges, are used, and both are marked in metrical and English dimensions. The tool room is not only carefully maintained at a regular temperature, in order to prevent the templates and jigs from varying in the course of their manufacture, but the appliances adopted have been selected so as to get the most precise results. In connection with the manufacture of large boiler taps, drill gauges, milling cutters, etc., a specially designed gas furnace has been built, with a number of compartments which can be used separately or collectively, according to the size of the tool being made. The toolsmith's forge is on the down-draught principle, so that, in addition to carrying off all smoke and dust, it tends to keep the atmosphere pure.

Amongst the principal machines used in this tool-manufacturing department is an 8-in. Whitworth self-acting, sliding-surfacing, and screw-cutting lathe, with a backing-off and taper-turning attachment. The milling, drilling, and grinding machines are all by the best makers. A 10-ft. machine is used for making the comparative measurements from existing standards. This machine, also of Whitworth make, has a measuring screw in a fast headstock with a large dividing wheel, one division of the latter representing 0.0001-in. in the end movement of the spindle. All transverse and tensile testing of bars is done in this department.

A check system is used in connection with the distribution of templates, tools, drawings, etc., and a separate store in the centre of the works is arranged for this purpose.

As to the boiler works, the fact that in 1905 the production was practically one boiler per week is, of itself, testimony to the nature of the plant adopted. The main boiler shop, together with its yard, has an area of 7000 square yards, and a height of 45 ft. to the crane rail, and is served by five overhead electric cranes, ranging in lifting power up to 100 tons, with numerous jib and other cranes associated with the various machine tools.

The machine tools fitted in the boiler works are all of a very powerful character; but only a few of these need here be referred to. There is a 13-ft. gap hydraulic plate-bending machine, which is entirely automatic in its action, and can be set to any radius to bend plates up to 2 in. thick when cold. The flanging for the front and back plates of boilers is done in an hydraulic machine, exerting a pressure of over 160 tons. This machine has four rams, two of which act downwards, one upwards, and the other horizontally. It is served by a special hydraulic jib-crane, capable of lifting the heaviest plates. There are also plate-edge planers and triple boring mills of corresponding power, while the vertical rolls take in plates up to 10-ft. wide.

For the riveting of the boilers there is a 13-ft. gap hydraulic riveting machine, capable of exerting a load on each rivet of 200 tons. The weight of this riveting machine alone is about 60 tons, and it is served by an independent hydraulic jib-crane. All the valves in connection with the crane and riveter are led to a common platform, so that one man is able to manipulate the whole of the work.

There is also a large installation of special plant for the manufacture of water-tube boilers, but it is scarcely necessary to describe this in detail.

A large part of the boiler work, especially for warships, is galvanised, and a special department has been organised for this purpose. The tubes, in the first place, are thoroughly cleaned, then placed in a zinc bath, and coated by electrolysis to the desired extent; the object being to expose defects, as well as to protect the tubes from corrosion during manufacture. The amount of work done is, perhaps, the best indication of the equipment of this department, as well as of the water-tube department; and this will be realised when it is stated that over 24,000 tubes are required for the boilers of one cruiser, and that six months suffices for their construction.

It would be possible to give other indications of the splendid equipment of the Works, but enough has been said to show that there is directed towards the realisation of the best work in all departments--firstly, the advantages of accumulated experience, carefully collated throughout two hundred years; secondly, the benefits which the psychologists claim for hereditary influence--applicable here not only through the proprietors, but also through many of the workmen; and, thirdly, a sound progressive spirit, which recognises the necessity for continual improvement in administration and design, and in machine tools and methods of manufacture.

FOOTNOTES:

[69] For further references to the rate of construction, see _Engineering_, vol. lx., page 813, where it is noted that ten vessels, aggregating 26,000 tons, were built for the China Navigation Company in nine months.

[70] See page 22, _ante_.

[71] See _Engineering_, vol. lxxx., page 418.

PRINTED AT THE BEDFORD PRESS, 20 AND 21, BEDFORDBURY, STRAND, LONDON, W.C.

End of Project Gutenberg's Two Centuries of Shipbuilding, by Various