The talk was given on 8th January 2014 at St Peters Church Hall, Henleaze.
and highlighted with many slides of drawings and illustrations. The history of the ship.
Challenging aspects associated with Corrosion Protection of the hull.
The design of the Original Engine.
The challenges presented in the construction of a light-weight replica engine.
Dr. Chivers explained that the talk would take 50 minutes and cover a brief history and restoration of the ship and would be in four
History & Corrosion Protection
The ship was the first Iron Hull, Propeller Driven, Steam Powered, Ocean going ship. That had the facility to be powered by steam or sail.
The ship was capable of accommodating 250 passengers with the first class midships and the third class in the stern. The engines were in
the midships section. The design was considered to be one of Brunels finest works and the average speed of the ship established at 9.5
The ship was first launched on 19th July 1843 and sea trials and maiden voyage took place in 1845. The ship was built to service
Trans-Atlantic passenger needs from Bristol. By this time there was the railway from London to Bristol and this was considered to be an
ideal link to service passengers from London en-route to New York and back.
The cost of a first class journey on the maiden voyage to New York was 35 guineas (about £ 2,500 now). Despite lots of pictures being
painted of the ship and heavy advertising and the issue of postcards of paintings to the wider public, there were only 45 passengers
aboard the maiden voyage.
A particularly spectacular painting was produced of the arrival of the ship in New York on 10 August 1845.
In 1846 between May and August there were two round trips over the Atlantic to New York, the route was from Liverpool round the Isle of
Man round coast of Northern Ireland to America but on 22nd September 1864 the ship ran aground in Dundrum Bay. From Sept 1846 to July 1847
the ship remained grounded and a great deal of work had to be carried out in order to lighten the ship to allow it to be floated. At this
time the original engines were removed and the details of their construction lost.
The ship was rebuilt in 1847 and continued to be used on the Atlantic crossing and also trips to Australia carrying thousands of immigrants.
One of the claims to fame was it carried the first English Test Team to Australia.
The ship was also used as a troop ship transporting the troops from UK to the Russian Crimea in the period 1853 to 1856.
The ship was converted to sail in 1881.
In 1886 the SS Great Britain was sold to The Falkland Island Company and used as a warehouse, quarantine ship and to store coal. In 1930
the ship was abandoned in Sparrow Cove where it remained until the 1950s when there was some interest shown in its recovery.
In the 1970s work began to patch the holes in the ship and the ship was towed to Bristol arriving in that year the ship was in a terrible
state with extensive hull corrosion that was exacerbated by the remains of the original propulsion system. The extent of corrosion below
waterline was the worst which was mainly caused by the evaporation of sea water and the residual chlorine. Despite the rain washing the
hull many of the plates could not be saved, but a policy of retaining as much of the original material as possible was adopted, based on a
projected life of 100 years. Several processes were considered using mechanical scale removal or a chemical process that would have the
added problems of effluent disposal. The main method adopted for the maximum preservation was to have the below waterline areas in a
humidity controlled environment.
To achieve this plates were placed along the water line to support glazed panels that have water between them and appear as if the ship is
in the sea. Below this in a sealed environment the air is maintained at a low humidity by pumping in dry air.
A book dealing with this period of the ships restoration between 1970 and the present day called The Incredible Journey has been written by
The Original Engine
The original steam driven machine was a Frances Humphrey design, the drive by paddle wheel. The engine had 72 inch stroke and 88 inch
diameter bore working on a pressure of 5 psi at 18 rpm and produced a 1000 horse power, giving the ship a speed of approximately 12 knots.
The gear to the prop shaft gave a 3 to 1 ratio and chain drives were used to reduce noise. The saltwater boilers were installed forward of
the engines. All this information has been gained from Wheal Plates that were produced to provide information of the original engineering
design but there is a great deal of doubt regarding their accuracy.
Later the drive was altered to a propeller propulsion based on the Archimedes screw principal this was a Brunel design about the 1840s.
The Replica Engine
In order to keep the weight to a minimum all the components were lightweight wherever possible and to minimise friction, roller bearings
were incorporated into the main bearings of the replica crankshaft. The position of the connecting rods in relation to the crank shaft were
not known so they were set at 180° apart although it is possible to set at 90°, 180° was accepted as being the safest setting.
The great Wheel attached to the crank shaft is 18 feet 2.5 inches diameter and the drive to the propeller shaft is by chain with drive
links every second link this arrangement was designed by Brunel and gives a ratio of just under 3 to 1.
In ships built around the same time the bolts and nuts had square heads but in the case of SS Great Britain hexagonal bolts and nuts were
Length: 322 ft (98 m)
Beam (width): 50.5 ft (15.4 m)
Height (main deck to keel): 32.5 ft (9.9 m)
Weight unladen: 1,930 long tons (2,161 short tons, 1,961 tonnes)
Displacement: 3,018 long tons (3,380 short tons, 3,066 tonnes)
Rated Horsepower: 1,000 horsepower (750 kW)
Weight: 340 tons
Cylinders: 4 x inverted 'V' 88 inches (220 cm) diameter
Stroke: 72 inches (180 cm)
Pressure: 5 psi (34 kPa)
RPM: Max. 20 RPM
Main Crankshaft: 17 feet (5.18 m) long and 28 inches (71 cm) diameter
Diameter: 15.5 ft (4.7 m)
Weight: 77 cwt (3,912 kg)
Speed: 55 RPM
Fuel capacity: 1,100 tons of coal
Water capacity: 200 tons
Cargo capacity: 1,200 tons
Cost of construction: £ 117,295
Restoration on the ship has continued from the date it first arrived in Bristol and it is now a popular venue for business dinners and
wedding celebration meals in the 1866 first class dining room.
In addition to the ship there is also the Brunel Institute Collections, where the national Brunel Archives are stored in addition a
location where Marine Books, Ships Plans and Ships Models can be purchased.
There followed a question and answer session:-
Q. Did you have any information about the type of metal used on the original engine bearings?
A. They were bronze or bronze dirivitives; white metal was generally used later.
Q. There is normally a corolation between engine speed and the speed of the ship of 7.5 rpm per knot what was the SS Great Britians
A. The engines gave 4 rpm per knot at a maximum speed of 54rpm, I do not know what changes happened when the engines were refitted after
the period of going aground in Dundrum Bay. There is however information on the design of propellers at various periods in time.
Q. Was there any parts of the old engines remaining when the ship returned to UK?
A. There was nothing left in the Falklands.
Q. The engines worked on steam at 5psi, why such a low pressure on a marine engine?
A. The idea in those days was to keep wear down to a minimum because of the long voyages the ship was designed to do.
Q. The design of the engine was more like those used for pumps than those used with smaller pistons for steam locomotion.
A. If you consider the date of the design it was very early on in the development of steam locomotion.
Q. Who paid for the development of the newer engine?
A. The Great Western Locomotion Company is thought to have provided the funds and they made a considerable loss.
Q. To allow the removal of the ship from Dundrum Bay who paid for the recovery?
A. Brunel was behind the project, but it is not known who provided the funds the ship was possibly sold.
Q. What was William Patterson’s role in the design?
A. The design of the ship was attributed to Brunel but it is difficult to see who was responsible for the major part of the ships engines
Q. I understand that the Great Eastern was the most successful ship of its time and the propulsion drive was paddle wheel and screw how
did this compare with the SS Great Britain?
A. Brunel was the king in engineering terms and what he wanted from the SS Great Britain was to be the best. By pushing the boundaries in
engineering the ship was considered the star of its day, but as with any innovative ideas, newer ships and designs develop, and take over.