THE BICENTENARY OF THE BIRTH OF

ISAMBARD KINGDOM BRUNEL.

An appreciation of the work of a pioneer engineer and naval architect through a MODELLING PROJECT.

Isambard Kingdom Brunel was born in 1806 and died in 1859. He was one of the heroes of my youth in that he showed the way in many avenues of engineering innovation. He was a successful civil engineer, mechanical engineer and not least a marine engineer. Tunnelling, bridge building, railroad building and innovative marine design and construction all fell within the scope of his achievements within his relatively short lifetime. He built the first steamship intended to cross the Atlantic, the Great Western in 1837; the first ocean screw-steamer, the Great Britain in 1843; and then the largest steamship built to that date, the Great Eastern in 1853. It could be said that his life was shortened through the intense effort he put into his work.

His father, Sir Marc Isambard Brunel settled in England in 1799 after fleeing the French revolution in 1793 to work firstly as an engineer in the USA and finally to develop many famous public works in England. Isambard Kingdom participated in many of these works. It was presumably the influence of his father’s career that carried him into his own career path.

My interest in Brunel’s engineering began when I visited the SS Great Britain during it’s preparation as a museum exhibit in Bristol, UK. My curiosity was further aroused when I toured the ship and realized that it was an excellent subject for a scale model. Building a model might also provide an interesting insight into the approach made by the engineers of his day to the numerous problems of design and construction in an age when the codes and standards were not available as they are today.

The construction processes for everything from riveting techniques to plate forming and fabrication of structural sections and components were an innovative adventure that must have been subject to a degree of trial and error. There was no CAD programme or method of finite element analysis to permit structural optimization or stress analysis. In view of the rough service life experienced by the hull and described so well in Ewan Corlett’s “The Iron Ship”, there must have been a good measure of intuitive overdesign to ensure its long survival. Apart from a number of original drawings I have not been able to find any recorded design detail.

I would very much like to have been an observer at his design meetings when problems were discussed. A tour of his design and draughting offices would also have been an experience. What kind of office lighting did the draughtsmen have? What kind of pencils or pens did they use? How did they reproduce the drawings? Was eyestrain a problem?

How well did Brunel understand the stress problems of sagging and hogging of these longer than usual hulls on the high seas? How did he evaluate the design of the screw? How was the power plant performance reconciled with the screw design?

There is one famous picture of Brunel posed by the side of an anchor chain which suggests that even the massive anchor chain might have been regarded as a major achievement in it’s day.

There is also the question of thermodynamic design of the steam plant. Handling of salt water supplied to the boilers and air extraction from the feed water must have been further problems to think about. I would be very pleased to hear from anyone who has any reference to the working environment of the day.

Modelling of the SS Great Britain.

The first decision I had to take was choosing the scale of the model. It had to be small enough permit reasonably easy transportation and yet not so small that replication of the steam plant details could not be achieved with reasonable facility. I eventually decided to limit the length of the hull to 75 inches resulting in a scale 60:1.

Procedure for construction of the hull has been completed and a set of lines prepared. All the mechanical design of the steam plant is complete and tooling as required for some of the more complicated components has been developed. Much of the crankshaft assembly has been completed and a miniaturized prototype of the steam supply timing valve has been constructed.

During the next few months this article will be extended as work proceeds. There is no completion date envisaged as yet but I will keep in touch by updating this article.

The adjacent illustration is of faceplate tooling for connecting rod boring, with a number of finished components including a timing valve, connecting rod and piston rod.

Trial assembly of the model engine room structure showing crankshaft, crankarms and the brass timing cams on the center of the crankshaft.

A tour of the ship will be added later