Part 3

One of the first steamers to trade in the Mediterranean was the _Superb_, sent thither in 1824, and the _Trinacria_, also built by the Scotts, followed in 1825. These ran between Naples and Palermo. The last-named vessel was 135 ft. long over-all, and 113 ft. 6 in. between perpendiculars, 39 ft. 6 in. broad over the paddle-box, and 21 ft. 10 in. net beam, 14 ft. deep (moulded), and of 300 tons burden. The vessel was especially well-equipped, and cost £15,000. The engines, the first manufactured by the Scotts at their Greenock foundry, were of 80 nominal horse-power, and the boilers, which were of copper, weighed 40 tons. The speed was 10 miles per hour. Later this steamer became the _Hylton Joliffe_, and was employed by the General Steam Navigation Company on their London and Hamburg service.

As to the yard in which these several vessels were built, suggestion is afforded of the state of efficiency by the following quotation from a history published in 1829.[31] "The building yard of Messrs. Scott and Sons is allowed to be the most complete in Britain, excepting those which belong to the Crown. It has a fine extent of front from the West Quay to the termination of the West Burn, and has a large dry dock, which was altered lately to the plan of the new dock. All the stores and lofts are entirely walled in, and, independently of the building premises, they have an extensive manufactory of chain cables."

The majority of the engines for these early steamers of the Scotts were constructed by Napier or Cook, and were of the side-lever or beam type. In 1825, however, John Scott, who had done so much for the progress of the firm, decided to commence building machinery, and acquired for £5000 the works which have since been developed into the well-known Greenock Foundry. This establishment was begun, although on a very small scale, about 1790,[32] and in its equipment, which was considered thoroughly efficient, there was included a large cupola. Some idea is given of the extent of the establishment by reference to Weir's "History of Greenock" (1829), page 94, where it is stated that in the few years that had elapsed since the taking over of the works by the Scotts "they have manufactured some splendid engines, and--what is more to be looked for than the appearance--they have wrought well. They have in hand the largest engine ever made, which is of a size of 200 horse-power, and is intended for a vessel building at Bristol. The number of men employed amount to about two hundred and twenty, while the weekly distribution of wages is £180." As a contrast, it may be said here that there are now four thousand men in the works, earning per week over £5500 in wages, and that the Scotts are engaged on the largest set of engines yet constructed by them--for H.M.S. _Defence_. They are of 27,000 indicated horse-power, to give the immense armoured cruiser named, of 14,600 tons displacement, a speed of 23 knots.

Since 1825, the Scotts have continued to do very satisfactory engine work, much of it of an original character, not only for vessels built for themselves, but for ships constructed on the Thames and other English rivers, and also for the series of warships built for the British Navy at their works, and for others constructed at the Royal Dockyards. This naval engine work began with H.M. ships _Hecla_ and _Hecate_, engined in 1838-9, and the first warships built in the dockyards to be sent to Scottish works to receive machinery.[33] And here it may be noted, too, that the first warship built by the Scotts was the _Prince of Wales_, in 1803, and also that the firm had the credit of building the first steam frigate constructed at Clyde works for the British Navy, H.M.S. _Greenock_, launched in 1839. They also built the first compound engines fitted to a French warship. With these naval ships and engines we deal in our next Chapter, and may therefore continue our narrative regarding merchant steamers.

We reproduce on the preceding page a drawing illustrating an early type of engine built by the firm. This is an engine constructed in 1831. The steam cylinder is 52-1/4 in. in diameter, and the crank-shaft is actuated, through connecting-rods, from the ends of the levers operated by the piston-rod, while the air-pump is placed at the opposite ends of the levers.

A different type of engine, constructed in the following year (1832), is illustrated on the facing page. In this case the cylinder operates the opposite end of the levers to that connected with the crank-shaft. In both engines the lever-gudgeon passes through the jet-condenser.

The records we have given are historically interesting, because they tell of the beginnings of a great epoch in British shipping. We do not propose to follow in such detail subsequent steamships, built for other services, between London and Aberdeen, the Clyde and Dublin, etc. The _City of Aberdeen_, built in 1835 for the first-named, marked noteworthy progress. She measured 187 ft. over the figure-head, and was of 1800 tons, including the space for the machinery. Her poop was 60 ft. long and 45 ft. broad. According to contemporary testimony, she was, in her day, the strongest steamer built, having solid frames from gunwale to gunwale. She had additional bracing with African oak stringers; oak and iron trussings alternately bolted to the stringers formed a complete system of diagonal fastenings and bindings from stem to stern. The whole of the cabins, saloons and state rooms, were on one deck, and there was the important innovation of hot and cold baths. The speed was 12 miles per hour.[34]

The _Jupiter_, of 439 tons and 210 horse-power, built in 1836 for the Clyde and Dublin trade, cost £20,000, and established a record in speed, making the voyage in sixteen hours six minutes, at the rate of 13 miles per hour; formerly the voyage took twenty-four hours.

In the late 'thirties and the early 'forties there was a great development in oversea trading steamers, the Clyde taking, then as now, the foremost place. Several epoch-marking voyages had been made with the steam engine used intermittently. The _Savannah_ had thus crossed the Atlantic from the United States in 1819, and the _Royal William_ from Quebec in 1833.

The barque _Falcon_,[35] 84 ft. in length, and of 175 tons, had, on the voyage to India in 1835 utilised engines which, however, were removed on her arrival in our Eastern dependency. Later in the same year the _Enterprise_, of 470 tons and 120 horse-power, also rounded the Cape of Good Hope to India. In all these cases, however, sails were utilised whenever possible, and there was still great hesitancy in accepting the steam engine even as an alternative on occasions to the use of the "unbought wind." The advantage, however, of a rate of speed which, while low, would be constant, soon asserted itself, and there followed within a few years regular mail steamship services on the North and South Atlantic Oceans, in the Mediterranean Sea, in the Indian Ocean, and the China Seas. In the beginning and development of these services the Scotts took a prominent part.

One of the first notable steamship lines to be organised for oversea service was that which ultimately became the Peninsular and Oriental Company. It had its origin[36] in steamship service from Falmouth to Oporto, Lisbon, Cadiz, and Gibraltar. Four steamers were built in 1836-37: the _Tagus_, _Don Juan_, _Braganza_, and _Iberia_. The first-named was built by the Scotts, and the third was engined by them. These ultimately carried the mails as far as Alexandria, whence they were conveyed overland to Suez, and from thence by the East India Company's vessels to Bombay. This service developed into the Peninsular and Oriental service, when, in 1840, the Company took over the mail service on the Indian Ocean; in 1847 they extended their operations to China. The overland service continued until the Suez Canal was opened in 1869, and many of the vessels for the Mediterranean service, as well as for the eastern route, were built by the Scotts.

The _Tagus_,[37] which was thus amongst the first of the P. and O. steamers, was built in 1837. She had a length of 182.1 ft., a beam of 26 ft., and a depth of 17 ft. 4 in., the burden tonnage being 709 tons. When carrying 265 tons of coal in her bunkers and 300 tons of cargo, the draught was 14 ft. 6 in. The side-lever engines which were fitted to her had a cylinder 62 in. in diameter, with a 5-ft. 9-in. stroke, developed 286 horse-power, and operated paddle-wheels 23 ft. 6 in. in diameter. Two of the other early steamers, the _Jupiter_ and the _Montrose_, were also constructed by the Scotts.

The conveyance of cargo and passengers across the Isthmus of Suez not only involved inconvenience and expense, but was a cause of great delay. There was still, however, a strong prejudice against steamships being utilised for long sea voyages, partly because of vested interests in sailing ships. Sir John Ross, C.B., who, in 1818 and in 1829 to 1833, made Arctic explorations, was one of the strongest advocates for a service to India by way of the Cape of Good Hope; and, in order to establish the feasibility of the undertaking, made experiments with the _City of Glasgow_, built by the Scotts in 1821. This vessel, of 283 tons, had in the interval been fitted with new boilers, with special safety appliances, and they worked at 4-lb. pressure; they gave the high evaporation in those days of 9 lb. of water per pound of coal.[38]

This vessel made the trip from London Bridge to the lightship off Spithead (246 miles) in thirty-one hours five minutes, on a consumption of 6 lb. of fuel per indicated horse-power per hour. These facts were utilised by Sir John Ross in his advocacy of the route, and a new company was formed, under his chairmanship, in 1837.

The first vessel of the fleet, named the _India_, was built and engined by the Scotts, and was a few years later transferred to the Peninsular and Oriental Company. The _India_, launched in 1839, was the largest steamer built on the Clyde up to that date, being 206 ft. 6 in. long, 30 ft. 9 in. beam, or 48 ft. wide over the paddle-boxes. The gross tonnage was 1206 tons. Accommodation was provided for eighty cabin passengers, and provision made for 400 tons of cargo. A feature of her construction was the provision of two strong bulkheads of iron across the engine-room, in order to avoid accidental outbreak of fire, and also to prevent water from a leak in one part spreading to another.[39] This was probably the beginning--nearly seventy years ago--of the system of division by watertight bulkheads, now universal. Its compulsory adoption was advocated by the Institution of Naval Architects in 1866, and enforced by Lloyds in 1882, and by the Board of Trade in 1890. The machinery was of 320 horse-power, and had surface-condensers. The _India_ was launched on the anniversary of the birth of James Watt, and a salute of twenty-one guns was fired as the vessel left the ways.

Five other steamers were built for the service, and the voyage took from fifty-five to sixty days, as compared with the one hundred and thirteen days occupied by the _Enterprise_. A monthly service was thus rendered possible. At the same time the Scotts built steam vessels for the coasting trade of India and of South Africa.

The type of machinery in use at this period is illustrated on the opposite page. This particular engine was constructed in 1838. The piston was connected to one end of the side-levers, while the crank was operated from the other. The paddle-wheel of this engine was 25 ft. 0-1/2 in. in diameter, with seventeen floats. For about thirty years this was the standard type of marine engine for paddle steamers.

The Gothic architectural design for the main framing was gradually abandoned for something less ornamental and perhaps more mechanical.

The Royal West India Mail Company's Service, still one of the best known of British lines, was commenced in 1841. Some of the steamers were purchased, but amongst those built originally for the service was the _Dee_ by the Scotts. She was 213 ft. 9 in. long, 30 ft. 4 in. beam, and 30 ft. in depth, the burden tonnage being 1848 tons. On a draught of 17 ft. 6 in. she carried 700 tons of cargo; and, as with most of the oversea liners of the period, the average speed was only about 8 knots. The voyage of 13,650 miles occupied then one hundred and nine days, including stoppages; and the consumption of fuel was 25-1/2 tons per day. The engines, which had cylinders 73 in. in diameter with a stroke of 7 ft., were of 450 horse-power, driving side paddle-wheels 28 ft. 6 in. in diameter.[40]

In the thirty years from the first commercial British steamer, the _Comet_, there had not been much advance in the steam engine, excepting in size, power, and, perhaps, reliability. Wood had continued to be the constructive material for all but the smallest ships. The size of vessels had grown steadily to the 1848 tons of the West Indian mail liner, which started regular steamship service almost contemporaneously with the inauguration of the Atlantic mail line by the Cunard Company in 1840. Speeds on service, even on the shortest routes, were seldom over 13 knots, and on the long routes under 8 knots. But this was in excess of the average attained by all but exceptionally fast clippers. The Table on the opposite page shows the progress made in thirty years.

TABLE I.--EPOCH-MARKING STEAMERS BUILT BY THE SCOTTS, 1819 TO 1841.

+------------------+--------+---------+-------+------------------ Year.| Name. |Tonnage.| Horse- |Speed | Remarks. | | |power.[A]|(Miles | | | | | per | | | | | Hour).| -----+------------------+--------+---------+-------+------------------ 1819 | _Waterloo_ | 200 | 60 | 9 |Largest steamer of | | | | | 1819. | | | | | 1820 | _Superb_ | 240 | 72 | 9 |Largest steamer of | | | | | 1820. | | | | | 1821 | _Majestic_ | 345 | 100 | 10 |Largest steamer of | | | | | 1821. | | | | | 1835 |_City of Aberdeen_| ... | 200 | 12 |Strongest steamer | | | | | of 1835. | | | | | 1836 | _Jupiter_ | 439 | 210 | 13 |Record speed | | | | | 1837 | _Tagus_ | 709 | 286 | 10 |Largest constructed | | | | | on Clyde, 1837, | | | | | and an early | | | | | P. and O. liner. | | | | | 1839 | _India_ | 1206 | 320 | 10 |First steamer to | | | | | India _viâ_ the | | | | | Cape and the first | | | | | Indian liner. | | | | | 1841 | _Dee_ | 1848 | 450 | 10 |First Royal West | | | | | India Mail liner. -----+------------------+--------+---------+-------+------------------

[A] It is difficult to determine in all cases the basis on which horse-power was computed. The figures given represent nominal horse-power, and in Sennett and Oram's "Marine Steam Engine" (page 3), the indicated horse-power is, for this early period, recorded as 1.8 times the nominal horse-power.

We enter now upon the period when iron took the place of timber as a constructional material. It was first used in part in the construction, on the banks of the Monkland Canal as far back as 1818, of a canal barge named the _Vulcan_, a vessel which continued at work for over sixty years.[41] But the first vessel built entirely of iron was a small craft constructed in 1821 in England. It was not, however, until 1832 that the first sea-going vessel was built of this metal. Progress in the adoption of iron was slow, largely because timber had proved so serviceable, and, with lessened restriction upon its importation, had become much cheaper. It was not until the higher strength and greater ductility of steel were demonstrated in the 'eighties that timber was finally superseded. The last wooden ship built by the Scotts was completed in 1859.

The firm built several of the early Atlantic liners, and we reproduce on page 32, as a further step in the development of the steam engine, a drawing showing the double-gear engines constructed early in the 'fifties for an iron screw steamer of 1190 tons, built for the Glasgow and New York service. This engine was pronounced at the time "the most compact specimen of its type then in existence,"[42] for although the power developed was 250 horse-power, and the ship was 260 ft. in length, only 12 ft. 6 in. of the fore-and-aft length was taken up by the machinery. "Every weight was well balanced, the working parts were clear and open, and the combined whole was stable, firm, and well bound together." The cylinders were 52 in. in diameter, were arranged diagonally, and worked at right angles to each other, with a stroke of 3 ft. 9 in. The piston-rods projected through the lower covers, to allow of long return connecting-rods. Each cylinder had two piston-rods, for greater steadiness, their outer ends in each case being keyed into a crosshead, fitted at each end with slide-blocks, working in a pair of inclined open guide-frames, bolted to the bottom cylinder cover, and supported beneath by projecting bracket-pieces, recessed and bolted down upon pedestal pieces on the engine sole-plate. From each end of this crosshead, immediately outside the guide-frame, a plain straight connecting-rod of round section passed up to actuate the main first-motion shaft. The upper ends of the connecting-rods were jointed to side-studs, or crank-pins, fixed in two opposite arms of a pair of large spur-wheels, which gave motion to the screw-shaft by means of a pair of corresponding spur-pinions, fixed on the shaft.

The main spur-wheels were 11 ft. 5-1/2 in. in diameter, and the pinions on the screw-shaft 4 ft. 6 in.; so that the screw propeller made 2-1/2 revolutions to each rotation of the engine. The arrangement ensured that each piston was directly coupled to both of the large wheels, and the increased length of the crossheads, which the plan involved, was counterbalanced by the effect of the double piston-rods, for by this division of the pressure the cross-strain leverage was proportionately diminished.

The use of steam expansively in multiple-cylinder engines was, however, the most important factor in the development of the steamship during the latter half of the nineteenth century.[43] With low steam pressures and simple engines the coal consumption, even for moderate-sized ships, was a serious item in a long sea voyage; and, early in the 'fifties, engineers, recognising the economy which would result from a successful compounding of steam, tackled the problems of steam-generation plant to enable the necessary high initial pressure to be developed with safety. John Elder had fitted several ships, but was, for a long time, content with an initial pressure of from 50 lb. to 60 lb. per square inch.

The late John Scott, C.B., was so convinced of the economy of steam at higher pressures in the compound system that he decided to build, largely at his own expense, a vessel which would enable him to put the system to a thorough test. This steamer, constructed of iron in 1858, was the _Thetis_, which was, undoubtedly, an epoch-marking ship, as her machinery was operated at an initial pressure of 115 lb. to the square inch--exceptionally high for those days.

For the first time, surface condensers were used in association with the compound marine engine. There were, as shown on Plate XI., facing page 36, six cylinders, arranged in two groups, each with one high- and two low-pressure cylinders. The three pistons of each group worked one crosshead, connecting-rod, and crank. Each group had two slide-valves, one for the high-pressure and one for the low-pressure cylinders, and both were attached to one valve spindle and one reversing link.[44] The engines worked up to 51 revolutions per minute--equal to a piston speed of 255 ft. per minute--and the maximum indicated horse-power was 256. The engines were tried by the late Professor Macquorn Rankine, F.R.S., who certified that the coal consumption on trial was 1.018 lb. per indicated horse-power per hour: an extraordinary result, even in the light of modern improvements.[45]

A large part of this efficiency was due to the boilers, which were of the Rowan water-tube type, and are illustrated on the opposite page. They had square vertical water-tubes, and through each of these there passed four hot-gas tubes. They evaporated 11 lb. of water per pound of coal, which was 30 per cent. higher than was attained with the best marine boilers of those days. The coal consumption at sea was about 1.86 lb. per indicated horse-power per hour.

Unfortunately, there soon developed small holes in the boiler-tubes, owing to erosion of the external surface, probably the consequence of the chemical action set up by the steam for cleaning the tubes mixing with the soot and other deposit.[46] Although for this reason this early water-tube boiler did not succeed, there is no doubt that the performances suggested improvements which have since brought complete success to this system of boiler. At the same time, the efficiency of high steam pressures was completely established and resulted in very considerable progress in the size and power of steamships.

Another innovation which suggested future developments was the fitting at the base of the funnel in the _Thetis_ of a series of water-tubes for the purpose of utilising the waste heat from the boilers to evaporate water for subsequent condensation to make up the boiler feed. The time was not ripe for such a utilisation of the waste gases--the heat was insufficient to generate the required steam--but now various schemes are applied for absorbing the waste heat in the uptake to heat air for furnace draught and to superheat steam.

A number of water-tube boilers were made, and a set was fitted into a corvette built for the French Navy. This vessel, completed in the early 'sixties, was the first ship in the French fleet to be driven by compound engines, and will fall to be described with other vessels in our next Chapter, dealing with the work of a century for the Navy.

Perhaps the most significant indication of the success of the Scott compound engine is found in the results of its application to the early Holt steamers. Alfred Holt commenced trading with the West Indies in 1855, while his brother, George Holt, became associated with Lamport in the River Plate trade in 1865. Both lines continue among the most successful in British shipping.