I should agree fully with both these arguments, but I think these advantages are fully counterbalanced by that of the experience in all the details which is brought into operation in an old-established manufactory, and the great relief from responsibility and risk obtained by contracting for the whole work.
The Directors having determined to make the engines, erected shops and fitted them up with proper tools. The services rendered to them by Mr. Brunel at this period were fully acknowledged at the next meeting of the shareholders.[126]
Mr. Brunel’s attention was now anxiously devoted to the consideration of the numerous questions involved in the construction of the ship and her engines; and, in order to obtain reliable information on many points, he sent one of his assistants, Mr. Berkeley Claxton, in the ‘Great Western.’ His sole occupation during six voyages was to note the amount of rolling and pitching, and the exact performance of her engines, with the effect of the use of the expansion valves on her speed, and on the consumption of fuel. These reports furnished Mr. Brunel with information which was of great value, especially when, shortly afterwards, he advised the Directors to adopt the screw propeller instead of paddlewheels.
The circumstances which led to the adoption of the screw propeller in the ‘Great Britain’ instead of paddlewheels were as follows:—
In the early part of the year 1840, the performances of the ‘Archimedes’ steamer began to attract the attention of scientific men. This vessel, which was fitted with the screw propeller patented by Mr. Francis Pettitt Smith, arrived at Bristol in May. A few trips were made up and down the Float, but the advantages of the screw propeller were not fully appreciated by those to whom they were explained.
But Mr. Guppy, who had attended some of these trials, went round in the ship to Liverpool. On his return he made a report to the Building Committee, and the Directors, on Mr. Brunel’s advice, passed a resolution delaying the progress of the engines of the ‘Great Britain,’ and of those parts of the frame which would be affected by any change of plans. Mr. Brunel was also requested by them to give his attention to the question of the adoption of the screw, and to report thereon.
During the next three months experiments were made by Mr. Brunel, assisted by Mr. Guppy and Captain Claxton, on the screw propeller in the ‘Archimedes.’[127] These experiments afforded ample opportunity of trying the performances of several forms of screws.[128]
On October 1, Mr. Brunel attended a special meeting of the Board, and read and explained a report he had drawn up, in which he laid before the Directors at great length the results of the different experiments he had made, and the advantages which he believed would attend the use of the screw propeller.[129] A resolution was passed adopting it for the ‘Great Britain.’
Mr. Brunel at first thought that he would be able to retain the form of engines which had been originally determined on for working the paddle wheels; but, on consideration, this was found impracticable. As the Company had by this time erected complete engine works, there could now be no question as to their undertaking the construction of the new description of engines required for working the screw propeller.[130]
Mr. Humphrys resigned the post of superintendent of the works, and Mr. Harman was appointed assistant engineer under Mr. Guppy, to whom the Directors, on the advice of Mr. Brunel, entrusted the supreme control of their manufacturing establishment.