The life of Isambard Kingdom Brunel, Civil Engineer Part 32

Brunel's first interview with Lord Minto; and she was then delivered to Messrs. Maudslay in the roughest possible state.

Except during the time that Mr. Brunel was prevented from attending to business by the half-sovereign accident, he was in constant communication with the dockyard authorities on matters relating to the construction of the s.h.i.+p, with Messrs. Maudslay as to the multiplying-gear and engines, and with Mr. F. P. Smith as to the forms of the various screws to be tried.

The engines and screw were fitted in the s.h.i.+p, after considerable delay; and, on October 24, 1843, Mr. Brunel reported on them in their completed state. On the 30th, the experiments were commenced.

More than twenty trials were made between that date and the following October, when the 'Rattler' went to sea, and Mr. Brunel could not of course any longer personally superintend the experiments; but, except on one or two occasions when his place was supplied by an a.s.sistant, all the trials that were made during the first year were conducted in his presence, and he transmitted the results from time to time to the Admiralty.[137]

The performance of the 'Rattler' was found to be satisfactory; and the position of the engines and screw being below the water line was so pre-eminent an advantage, that in 1845 the Lords of the Admiralty ordered more than twenty vessels to be fitted with the screw;[138] and since that time it has gradually superseded the paddlewheel for s.h.i.+ps of war.

The services which Mr. Brunel rendered to the country during the whole of these proceedings were given entirely without pecuniary recompense, and in the face of opposition and discouragement; but he had the satisfaction of knowing that he had been mainly instrumental, not only in introducing the screw propeller into the mercantile navy, but also in securing its adoption in Her Majesty's fleet.

CHAPTER XI.

_STEAM NAVIGATION--THE 'GREAT EASTERN' STEAM-s.h.i.+P, FROM THE COMMENCEMENT OF THE UNDERTAKING TO THE LAUNCH._

A.D. 1851--1857. aeTATIS 46--52.

INTRODUCTORY OBSERVATIONS--THE AUSTRALIAN STEAM NAVIGATION COMPANY--STATEMENT OF MR. BRUNEL'S PROJECT OF A LINE OF LARGE s.h.i.+PS (JUNE 10, 1852)--ADOPTION OF HIS PLANS BY THE EASTERN STEAM NAVIGATION COMPANY--EXTRACT FROM A LETTER DESCRIBING THE SCHEME (JULY 1, 1852)--LETTER TO J. SCOTT RUSSELL, ESQ., ON THE FORM AND DIMENSIONS OF THE GREAT s.h.i.+P (JULY 13, 1852)--REPORT ON MODE OF PROCEEDING (JULY 21, 1852)--REPORT ON ENQUIRIES RELATING TO THE DRAUGHT AND FORM OF THE VESSEL (OCTOBER 6, 1852)--REPORT ON THE PROCEEDINGS OF THE COMMITTEE APPOINTED TO CONSIDER MR. BRUNEL'S PLANS (MARCH 21, 1853)--TENDERS INVITED FOR THE s.h.i.+P AND ENGINES--REPORT ON TENDERS (MAY 18, 1853)--PREPARATION OF THE CONTRACTS AND SPECIFICATIONS--EXTRACTS FROM MR. BRUNEL'S MEMORANDA (A.D. 1852, 1853, 1854)--LETTER ON HIS POSITION AND DUTIES AS ENGINEER OF THE COMPANY (AUGUST 16, 1854)--LETTER ON AN ARTICLE IN A NEWSPAPER (NOVEMBER 16, 1854)--REPORT ON THE UNDERTAKING (FEBRUARY 5, 1855)--ARRANGEMENTS PROPOSED FOR OBTAINING ASTRONOMICAL OBSERVATIONS--LETTER TO G. B. AIRY, ESQ., ASTRONOMER ROYAL (OCTOBER 5, 1852)--APPOINTMENT OF MR. WILLIAM HARRISON TO THE COMMAND OF THE s.h.i.+P--MEMORANDUM ON THE MANAGEMENT OF THE GREAT s.h.i.+P (OCTOBER, 1855)--LETTER ON THE DUTIES OF THE CHIEF ENGINEER (MARCH 19, 1857)--SUSPENSION AND RESUMPTION OF THE WORKS.

Mr. Brunel's earlier labours in connection with the progress of Ocean Steam Navigation have been described in the chapters on the 'Great Western' and 'Great Britain' steam-s.h.i.+ps.[139] The 'Great Eastern' is but the result of the application, under different circ.u.mstances, of the same principles which had guided him in his previous under-takings, the practical working out of the 'idea which he had frequently entertained, that, to make long voyages economically and speedily by steam, required the vessels to be large enough to carry the coal for the entire voyage at least outwards; and, unless the facility for obtaining coal was very great at the out port, then for the return voyage also; and that vessels much larger than had been previously built could be navigated with great advantage from the mere effect of size.'[140]

In 1851, four years after the release of the 'Great Britain' from Dundrum Bay, Mr. Brunel became again connected with the construction of steam-s.h.i.+ps. In that year he was consulted by the Directors of the Australian Mail Company upon the cla.s.s of vessels which it would be advantageous for them to purchase, in order to carry out their contract for the conveyance of the mails to Australia. He advised them to have s.h.i.+ps of from 5,000 to 6,000 tons burden, in order that they might only have to touch for coal at the Cape.

Some of the Directors would not hear of so startling a proposition; but they nevertheless asked Mr. Brunel to become their Engineer; and he retained the post till February 1853. Two s.h.i.+ps were built under his direction by Mr. J. Scott Russell--the 'Victoria' and the 'Adelaide.'

It was, no doubt, his connection with the Australian Mail Company that led Mr. Brunel to work out into practical shape the idea of 'a great s.h.i.+p' for the Indian or Australian service, which had so long occupied his mind; and it appears that in the latter part of 1851 and the beginning of 1852 he devoted much time and thought to the subject. He collected facts relating to the trade with India and Australia which demonstrated the advantages to be gained by a rapid and direct communication for the conveyance of pa.s.sengers and troops, as well as of merchandise. It was with these enlarged views that Mr. Brunel entered upon the construction of the 'Great Eastern.' He writes in February 1854, 'In February and March 1852 I matured my ideas of the large s.h.i.+p with nearly all my present details, and in March I made my first sketch of one with paddles and screw. The size I then proposed was 600 70, and in June and July I determined on the mode of construction now adopted of cellular bottom; intending then to make the outer skin of wood for the sake of coppering.'

In the spring of 1852 he communicated the results at which he had arrived to Mr. John Scott Russell, Captain Claxton, and other scientific friends, and also to several Directors of the Eastern Steam Navigation Company.

This Company had been formed in January 1851 for the purpose of establis.h.i.+ng an additional line of steam communication by the overland route, for the conveyance of mails, pa.s.sengers, &c., between England, India, and China, with a branch to Australia. However, in March 1852 the Government determined to grant the contract for the whole service to the Peninsular and Oriental Company. The Directors of the Eastern Steam Company were therefore obliged to report to their shareholders that the object for which the Company had been incorporated could not be carried out.

At about this time Mr. Brunel's scheme was brought before the Directors, and he submitted to them a detailed statement of his project.

After describing the size and capacities of the vessels then used on the route between England and the East, and the amount and cost of the coals they consumed, he continued:--

June 10, 1852.

The same amount of capital and the same expenditure in money for fuel now required for a line of s.h.i.+ps of the present dimensions would build and work s.h.i.+ps to carry in the year double the number of pa.s.sengers, with far superior accommodation, and in about half the time, and two or three times the amount of cargo; the whole difference being produced simply by making the vessel _large enough to carry its own coal_, exactly as when the 'Great Western' was projected for the New York line, the pa.s.sage had been considered an impossible one for steamboats, or, if possible, only at a total sacrifice of all return for the cost. Certainly, no steamboat then built could get across except by a chance fair weather pa.s.sage, and then only by being completely filled with coals and leaving no room for pa.s.sengers or cargo. Simply by building a s.h.i.+p of the size necessary to take the coal, over and above the accommodation required for a due number of pa.s.sengers and a reasonable quant.i.ty of cargo, the pa.s.sage was rendered perfectly easy and certain, and has since become a mere matter of course, and an ordinary and profitable trading voyage.

The increased size, instead of being a disadvantage, was found, as predicted by the projectors, to be a great benefit, and gave increased speed, even beyond that proportionate to the power; and this steamboat, built in 1836, is still as good as any of her size afloat.

Nothing more novel is proposed now, but again to build a vessel _of the size required to carry her own coals for the voyage_. The use of iron, which has since 1836 become common, removes all difficulty in the construction, and the experience of several years has proved, what was believed before by most unprejudiced persons, that size in a s.h.i.+p is an element of speed, and of strength, and of safety, and of great relative economy, instead of a disadvantage; and that it is limited only by the extent of demand for freight, and by the circ.u.mstances of the ports to be frequented.

A Committee was appointed to confer with Mr. Brunel and with Mr. Scott Russell, 'who was fully acquainted with all Mr. Brunel's plans, and had ably a.s.sisted him in maturing them.'[141]

The Committee reported to the Directors that they had met on the day after their appointment, when, Mr. Brunel being unavoidably absent, Mr.

Russell had attended and entered into a very full explanation of Mr.

Brunel's plans, and that a long investigation of his proposition had taken place; that a few days later they had met again, when Mr. Brunel attended, and that after a further and most satisfactory investigation, they had come to an unanimous decision in favour of the scheme. This resolution was adopted, and Mr. Brunel was appointed Engineer to the Company.

The following extracts from his reports and correspondence carry on the narrative till the date of the next meeting of the shareholders (December 1, 1852), when the details of the project were laid before them:--

_Extract from a Letter describing the Scheme._

July 1, 1852.

The principle is, as I explained to you, a very simple one--that of building s.h.i.+ps to carry their own coals, instead of incurring large expenses and great delay in coaling at numerous intermediate stations; and the result is a large vessel certainly, but one which, at the same cost of fuel as is now required for small ones, has, besides that room, for 4,000 or even 5,000 tons (measurement) of cargo, and as many pa.s.sengers as offer. Thus the capital embarked in the one vessel is not so great in proportion to the tonnage s.p.a.ce for cargo as the capital embarked in several smaller vessels carrying the same amount; while the current expenses are greatly less, and the speed, and economy of time by that speed and by avoiding tedious stoppages, greatly in favour of the large one.

Practical men concur with me, not merely in the practicability of constructing the vessel, but in the great advantage as regards speed, seaworthiness, and safety resulting merely from the increased size; while all the mercantile men concur in the opinion that if goods can be carried direct in thirty to thirty-five days, the certainty of freight ensures a return far beyond all present proportion of return to cost.... On these points, of course, I quote only the opinions of the Directors. On the mechanical part I offer my own opinion, and may quote those of the first practical men of the day--Messrs. Maudslay, Messrs. Watt and Co., and J.

Scott Russell, all of whom have a.s.sisted me in the project, and are prepared to join in it.

_Letter to J. Scott Russell, Esq., on the Form and Dimensions of the Great s.h.i.+p._

July 13, 1852.

The adoption of this plan being now determined upon, we must proceed to determine the details, and the first step unquestionably is the determination of the size and form of the s.h.i.+p. Now, in preparing the general design, I think the following conditions should be strictly complied with. If any of them appear to involve any great sacrifice in cost, or to involve any other peculiar difficulties, these difficulties can be considered afterwards; but the wisest and safest plan in striking out a new path is to go straight in the direction which we believe to be right, disregarding the small impediments which may appear to be in our way--to design everything in the first instance for the best possible results strictly according to the principles which theory, so far as it is supported by practice, teaches us, and without yielding in the least to any prejudices now existing unsupported by theory and practice, or any fear of the consequences; we can then afterwards weigh and balance deliberately the advantages of adhering to or giving up this or that particular part, or modifying dimensions, either from motives of economy, or as yielding to public opinion from motives of policy.

In determining the lines of the s.h.i.+p, for instance, I should adopt that which we have reason to believe the best possible without any concession, or any compromise or regard to any a.s.sumed difficulties of construction, or regard to a.s.sumed opinions; these difficulties will very likely vanish afterwards if disregarded in the first instance, as in the case of the continuous curve, in which my fresh ideas had the advantage even of your much greater knowledge, hampered by a little preconceived idea. With respect to the size, to arrive at it by constructive calculations from the fixed conditions that we can lay down is perhaps possible, but rather difficult, and I think we know sufficiently nearly now what the minimum size must be to work upon; that, and a trifling alteration afterwards in the scale, will suffice to bring it to the exact required capacity.

The positive conditions, then, are a maximum draught of water of 24 feet, when leaving the Hooghly with the coals for the voyage home; and the capacity must be at least 21,000 tons of displacement at this draught of 24 feet.

I think you will find that to effect this comfortably you must give a length of 650 feet at least, and an extreme breadth of 80 feet, but this beam of 80 feet requiring no fuller entrance than you would make with a beam of 70 feet, the 80 feet being obtained entirely by continuing a gentle curvature throughout the whole length, instead of having any parallel lines.

If the experiments upon the friction of surfaces turn out as I hope, and give us reason to expect a very much less resistance from a copper surface than that now created by painted iron, I suspect we may be led rather to increase our length and diminish the proportion of beam; but this is a very serious question, not entirely dependent on the consideration of the form of least resistance including friction, but also materially affected by the consideration of the advantages of the extreme steadiness of motion which length seems to give. It is a subject which must be well discussed and well considered, with the a.s.sistance of all those whose opinions and experience are likely to be of use to us. My own impressions, I confess, derived from considering the cases which we have, even after the striking result of the 'Ocean Queen,' are that positive length, independently of relative length, has much to do with it. When I see that the 'Great Britain,' although with a beam of about one-sixth of her length at the water line, and a mids.h.i.+p section favourable to rolling, is nevertheless steady, I must conclude that positive length may compensate very greatly for a relatively wide beam. Now, we shall unquestionably have abundance of positive length. We must then be careful not to sacrifice much to keep a small beam, without being very sure that there are very great advantages; and, except for the a.s.sumed advantages of the long parallel or equal bearings, the form of least resistance, including friction, with a draught limited to 24 feet, and a required displacement of 21,000 tons, would, I apprehend, give us a beam nearer 90 feet than 70 feet. I should like to know exactly what the proportion would be without regard to the theory of the long narrow parallel forms; and then let us consider how much, if anything, should be sacrificed to attain the advantage a.s.sumed to be attained by relative length.

Let us therefore have at once the draft of a vessel of 21,000 tons displacement at the 24 feet water line, and of such form as will in your opinion give the greatest speed in smooth water, without seeking to make it narrow.

We must, of course, also bear in mind the comparative weakness of form caused by length, and the consequent increased thickness of material required, besides an actual increase of surface, involving a very considerably greater quant.i.ty and weight of material in the s.h.i.+p, which last consideration is very greatly in favour of breadth of beam; for I think you will find that the quant.i.ty of iron in two s.h.i.+ps of 600 and 700 feet in length respectively, with the same displacement and the same ultimate strength to resist strains, will be fully in the ratio of their length.

_Report to the Directors on Mode of Proceeding._

July 21, 1852.

Since the adoption by the general meeting of the plan recommended by the Directors, I have been engaged very constantly in maturing the details of that plan, and considering the course which it would be necessary to follow in order to carry them out in the surest, safest, and most efficient manner.

The steps which are about to be taken are unquestionably in the right direction, but they are considerable ones, and must be taken with deliberation and certainty, and without leaving anything doubtful; and, when determined upon, they must be followed up with decision.

Although you will probably determine upon constructing not less than two vessels in the first instance, yet they must both be proceeded with at once, and must in fact be exact duplicates of each other. The success of the two, therefore, depends upon that of each; there can be no average struck in such a case, but the two s.h.i.+ps must be designed and executed on such principles and with such perfection that no doubt can exist of the result.

By well considering all that has been done, by selecting all that has been most successful, and by a judicious application of such results to the peculiar circ.u.mstances of our case, all this certainly can, I think, be a.s.sured, but it can be a.s.sured only by proceeding with the caution and the decision which the circ.u.mstances demand.

In the first place, as to the designing of the whole, the principle being determined upon, much may be ascertained by mere calculation, but for these calculations data are required, which nothing but experience can furnish. I have, therefore, availed myself of the a.s.sistance of those most competent to afford the required information. I have called in to my a.s.sistance the gentlemen whom I had already named to you as best able to give strength to our position by the value of their opinions, and best able to execute the various parts of the work with that experience and perfection which are essential to our success.