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.
[Illustration: AN ENGINE OF 1832.]
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.
[Illustration: Plate X. SCOTTS' FIRST P. AND O. LINER, THE "TAGUS."]
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.
[Illustration: TYPE OF SIDE-LEVER ENGINE OF 1840.]
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.
[Illustration: DOUBLE-GEARED ENGINE FOR EARLY ATLANTIC LINER.]
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.
[Illustration: A PIONEER IN WATER-TUBE BOILERS.]
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.
The Holt steam line to China was commenced in 1865, and was the only
one _viâ_ the Cape of Good Hope which proved at once successful.
Built and engined by the Scotts, the early Holt liners, starting from
Liverpool, never stopped till they reached Mauritius, a distance of
8500 miles, being under steam the whole way, a feat until then
considered impossible.[47] Thence the vessels proceeded to Penang,
Singapore, Hong Kong, and Shanghai. Unaided by any Government grants,
they performed this long voyage with great regularity.
[Illustration: Plate XI. HIGH-PRESSURE MACHINERY IN THE "THETIS."]
The three vessels which inaugurated the very successful Holt line were
named _Agamemnon_, _Ajax_, and _Achilles_, and were built of iron
by the Scotts in 1865-6. They were each 309 ft. in length between
perpendiculars, 38 ft. 6 in. beam, and 29 ft. 8 in. in depth, with
a gross tonnage of 2347 tons--dimensions which were then deemed too
great for the China trade, but which experience soon proved to be
most satisfactory. Sails were fitted to the vessels, as shown in the
engraving on the Plate facing page 40.
Alfred Holt was the first to apply the compound engine to long voyages,
and his vessels were the earliest of the type built for the merchant
service by the Scotts. It is true the Pacific Company had compound
engines fitted to one or two ships prior to this, but these were only
used in the coasting trade. The engines of these Holt liners are
therefore of historical interest, and general drawings are reproduced
on the next page and on Plate XII. A feature in these liners was that
the propeller was abaft the rudder, which worked in an aperture in the
deadwood corresponding to that for the propeller in single-screw modern
ships.
A detailed description from the specification of the machinery may
be reproduced, as it indicates the practice of the Scotts for a
considerable time. Indeed, this type of compound engine, with slight
modifications, was the standard engine for Holt liners until the advent
of the triple-expansion engine. The details follow:--
The cylinders were: high-pressure, 30 in. in diameter; low-pressure,
62 in. in diameter, with 4 ft. 4 in. stroke, arranged vertically in
tandem fashion, with the low-pressure cylinder on the top. There were
two connecting-rods, but a common crosshead for the tandem cylinders,
and a common crankpin.
The crankshaft was 13-1/2 in. in diameter, with a bearing 30 in. long
at the aft end of the bedplate, which took the propeller thrust. The
propeller was three-bladed, 17 ft. in diameter, with 26 ft. 6 in.
pitch; with 46 revolutions per minute the piston speed was 400 ft.
per minute. To ensure smooth working with the single crank, a heavy
flywheel was fitted, and the pump levers carried a massive weight to
help to balance the weight of pistons and rods.
[Illustration: THE MACHINERY OF THE "ACHILLES."]
The condenser had 420 tubes 1-1/2 in. in diameter, giving a cooling
surface of 1375 square feet. The tubes were arranged in three nests,
the water circulating through the top one first and the bottom one
last. The circulating pump, instead of forcing water through the
tubes, as was usual in such case, sucked from the condenser and
discharged directly overboard. There were: one air pump, 24 in. in
diameter; one circulating pump, 24 in. in diameter; two feed pumps,
4-3/4 in. in diameter; and one bilge pump 7 in. in diameter: all the
pumps were single-acting, with 17 in. stroke. The diameters of the
principal pipes were: main steam, 7-1/2 in.; to low-pressure cylinder,
12 in.; circulating inlet, 10 in.; discharge, 12 in.; air-pump
discharge, 10 in.; main feed, 3-3/4 in.; and waste steam, two at 6 in.
in diameter.
The two boilers were double-ended, of the locomotive type, with
wet-bottomed furnaces. The centre was cylindrical, but the ends were
rectangular with semi-cylindrical tops, the total weight, without
water, being 78 tons. Each boiler had a long receiver passing through
the uptake to dry the steam. On the receiver was a deadweight
safety-valve 6-1/4 in. in diameter, to suit a working pressure of 60
lb. per square inch. The grate surface was 112 square feet, and the
total heating surface 4506 square feet, there being 328 iron tubes 4
in. in diameter.
[Illustration: Plate XII. GENERAL ARRANGEMENT OF THE MACHINERY OF THE
"ACHILLES."]
The three pioneer ships of the Holt line--the _Agamemnon_, _Ajax_, and
_Achilles_--proved most economical. The _Achilles_ came home from China
in fifty-seven days eighteen hours, net steaming time, or, including
the stoppages at ports, sixty-one days three hours. She travelled
during this period a distance of 12,352 miles, on a consumption of
coal which did not exceed 20 tons per day for all purposes,[48] equal
to 2-1/4 lb. per unit of power per hour, which for those early days,
with comparatively low steam pressures, must be regarded as a highly
satisfactory result.
The non-stop voyage between Liverpool and Mauritius was made as early
as 1866 in thirty-seven days, equal to 10 knots, with a number of
passengers and a fair cargo. The higher economy established for the
compound engine on long voyages resulted in the ultimate supersession
of the sailing ship.[49] Thus the Scotts, while still enjoying the
credit of the splendid performance of the _Lord of the Isles_ in the
early 'sixties, produced at their foundry the Holt compound engine,
which sounded the death-knell of the clipper. The compound system had
at once an influence on the size of ships. Up till 1862 no ship of
over 4000 tons had been constructed, with the exception of the _Great
Eastern_; by 1870 there were fifteen; by 1880, thirty-seven.[50]
The Scotts, aided by Holt, continued their research towards higher
economy, and a large fleet of steamers was built, with engines having
flywheels which, it was found by experience, considerably improved the
economy up to a certain stage, although with increased pressure the
proportion of saving was not commensurate with the weight of the wheel,
and the three-cylinder three-crank engine was ultimately adopted.