Even before the Great Western
had completed her second transatlantic crossing Brunel was
busily preparing the plans for her successor, the Great Britain.
In the early 1800's Britain was engaged in the Napoleonic
wars and during that time much of the trans-Atlantic trade
had been taken over by the Americans. The Great Western Railway
Company in a bid to redress the imbalance of trade sought
to build a vessel and, as Brunel was the company's chief engineer,
who better was there to complete the task.
The initial sketches were for
a wooden paddle-steamer and Brunel had deduced that the space
required for bunkers was proportionately less in a larger
vessel and that, consequently, speed could be greater. Before
the keel was laid in 1839 Brunel was able to examine a small
iron built vessel, the Rainbow, and immediately changed the
construction of the Great Britain to iron even thought the
timber had already been purchased. The design was further
amended in 1840 after Brunel had seen a small screw-driven
ship, the Archimedes, which visited Bristol. After delaying
construction for several months while he studied the concept
he concluded that the new screw propulsion was superior to
paddles and changed the plans accordingly.
Brunel, in essence, was a civil
engineer rather than a naval architect and the building of
the Great Britain presented new problems which had to be overcome.
The hull was plated with 6' x 3' sections each overlapped
clinker-style and riveted. The traditional bluff bow of the
day was replaced with a fine bow with hollow lines, a style
which was later adopted by the sailing clippers. As ship owners
were not convinced that a ship could be powered by steam alone
the Great Britain had six masts to carry sail. Only one of
the masts was stepped on the keel, the remainder being fitted
to hinged bases on the deck. The funnel was located between
the second and third masts.
The engines Brunel used were
based on an earlier design of his father, Sir Marc. Intended
to drive the paddle wheels which required athwartships placement
Brunel merely turned them 90 degrees to provide power to a
fore to aft propeller shaft. Even so, the crankshaft, driven
by two double-acting twin cylinders beneath the shaft, was
intend to power high mounted paddle wheels and not a low positioned
propeller shaft. Brunel solved this problem by installing
a massive chain drive. A shaft between the engines was fitted
with an 18' diameter sprocket. Four chains then transferred
the drive to a small sprocket on the propeller shaft which
was positioned between the cylinders. The shaft turned by
the engines revolved 18 times per minute but the simple method
of gearing enabled the propeller shaft to turn at 53 rpm.
The propeller shaft was constructed of forged steel plates
with an internal diameter of around 30", large enough
to allow a boy to slither in to hold the dolly during riveting.
A lithograph by T Picken after a painting by Joseph Walter
of the launch of the Great Britain at Bristol on 19th July
1843 (NMM)
Early photograph taken by Fox Talbot of the Great Britain
fitting out at Brandon Wharf, Bristol
during April/May 1844 (Talbot Collection)
An 1845 engraving of the Great Britain with her original rigging.
(Mary Evans Picture Library)
When it came to the design
of the propeller Brunel had to start from scratch and establish
new principles. The end result was a six-bladed unit some
15' 6" in diameter and weighing 4 tons. The performance
of Brunel's propeller compares favourably with the six-bladed
propellers fitted to the modern day tankers. The steering
gear installed did not differ substantially from that used
by sailing ships. The steering wheel was located aft but the
rudder was balanced, i.e. a small area of blade extended forward
of the rudder post. This lightened the control and enabled
more precise maneuvering .
Completed, the Great Britain
was 322' long with a beam of 51' and a registered tonnage
of 1016 GRT. She had berths for 252 passengers but up to 360
could be carried using settees and other sleeping arrangements.
The crew numbered 130. In addition to carrying passengers
she had space for up to 1200 tons of cargo. She carried 20
days supply of coal, well in excess of the requirement for
an Atlantic crossing of 14 days. The ship cost £117,295
6s 7d to build and, as there was no existing yard big enough
to build a ship of that size at that time, the owners had
to provide their own facilities at a cost of £53,081
12s 9d.
The Great Britain was launched
by Prince Albert, Queen Victoria's Consort, in July 1843,
at least, in theory. The entrance to the dry dock in which
she had been built was too narrow and the ship stuck fast.
The masonry and brickwork had to be broken away before the
ship could be released. After being grounded for an overhaul
the Great Britain was moved into a floating harbour for fitting
out. On 11th December, 1844, under the supervision of Captain
Claxton, the ship was eased through the lock on a spring tide
and proceeded under sail to London. Once there she was inspected
by Queen Victoria and had her engines installed.
From London the Great Britain
proceeded to Liverpool where, under the command of Captain
James Hosken, she commenced her maiden voyage on 26th July,1845.
In addition to 50 passengers who had paid between 20 and 35
guineas she carried 600 tons of cargo and completed an uneventful
voyage in 14 days 21 hours entirely under steam. During the
second voyage to New York with 102 passengers the ship suffered
a minor stranding and an inspection revealed that the propeller
had shed a blade. A second blade was removed to compensate
but on the return voyage she shed three more and had to complete
the voyage under sail. The journey took only 20 days which
proved the Great Britain could perform well under sail.
A painting by Joseph Walter of the Great Britain at Bristol
in January 1845 (J.C.G.Hill)
Engraving of the grand saloon as it after the refit in 1852
(Illustrated London News)
