The life of Isambard Kingdom Brunel, Civil Engineer Part 33

With respect to the form and construction of the vessel itself, n.o.body can, in my opinion, bring more scientific and practical knowledge to bear than Mr. Scott Russell. As to the proportion of power to be adopted, the form and construction of the engines, screw, and paddles, besides Mr. Scott Russell, I have had the benefit of the deliberate consideration and advice of Mr. Field, of the firm of Maudslay and Field, and of Mr. Blake, of the firm of Watt and Co. I have written also to my friend Mr. F. P. Smith, to whom the public are indebted for the success of the screw, for his advice on the subject. With such a.s.sistance I think we may rely upon the certainty of being able to design and to execute all that is best in the mechanical and s.h.i.+p-building department. In the naval department I have had the opportunity also of consulting two gentlemen, Captain Claxton and Captain Robert Ford, who possess special knowledge and experience on the subject. I have had several conferences with all these gentlemen, I have explained fully my views, and, with their a.s.sistance, settled preliminarily some of the princ.i.p.al points of detail. What I should propose to the Directors now is, that with that a.s.sistance I should proceed to prepare in detail the design of the s.h.i.+p, and the exact dimensions and form of the engines; that, in the meantime, I should obtain information upon certain points which will govern you as to the mode of contracting for the construction of the s.h.i.+ps, and also that I should be authorised to adopt some means of determining one or two most important points which must govern some of the princ.i.p.al dimensions.[142]

_Report to the Directors on Enquiries relating to the Draught and Form of the Vessel._

October 6, 1852.

Since the date of my last letter to you, recommending that certain enquiries and investigations should be set on foot to determine several points which would materially influence the plans I should have to submit to you, many circ.u.mstances have occurred to delay these investigations. Not having sent any competent person expressly to Calcutta to ascertain with certainty the draught of water that might be adopted, I have endeavoured to obtain as much information as possible upon this point from persons capable of affording it, who might be in England.

Several very competent men, captains of long experience in that particular navigation, and even local pilots of the first standing, happened to be within reach, and I have had personal communication with these gentlemen. Notwithstanding, however, these fortunate opportunities of obtaining information from the best existing authorities, we are left in pretty nearly the same state of doubt as to the maximum depth as we should be by a mere inspection of the charts, the opinion of very competent men varying so much as to fix this maximum as low as 21 and as high as 23 and even 24 feet. They all concur, however, in fixing Diamond Harbour as the point in the Hooghly which may easily be reached, but beyond which it would be almost impossible to go.

A question as to the extent of swell which in so large a s.h.i.+p might be given to the sides, increasing the capacity without materially increasing the resistance, involved one of the experiments to which I referred in my former letter; these experiments have been made, and the result, such as it was, of the enquiries before referred to as to the navigation of the Hooghly, led me to direct the preparation of draughts of three different models of s.h.i.+ps, and upon further consideration of these three, and under the circ.u.mstances, I have come to the conclusion of recommending one which will have the following dimensions:--namely, 670 feet in length, 85 feet beam, and a deep water draught of 30 feet.

Such a vessel would be able to carry her own coal for the voyage home out of the Hooghly with about 23 feet draught; but if between now and the period when the exact arrangement must be determined, it is found expedient not to attempt so great a draught in the Hooghly, the same vessel will, by coaling at Trincomalee on the return voyage, be exactly adapted to work out of the Hooghly with a good cargo of goods and coals for Trincomalee with only 20 to 21 feet draught.

I have been in communication with the eminent engine builders whose names I have mentioned on a former occasion, and with Mr. F. P.

Smith, the inventor of the screw propeller. Some trials and investigations are still in progress to determine the relative advantages of a copper and iron bottom, on which question may depend the arrangements which may be requisite to provide for docking or rather laying up for cleaning, and when these points are determined I shall be prepared to lay before you a complete design of s.h.i.+p and engines for your consideration.

Efforts were made to induce the public to a.s.sist in carrying out the project. In February 1853, the Chairman (the late Mr. Henry Thomas Hope) and several of his colleagues formed themselves into a committee for the purpose of communicating with Mr. Brunel on the subject of his plans, and reporting to the Board thereon.

The results of this conference were embodied in the following report which Mr. Brunel addressed to the Directors:--

_Report on the Proceedings of the Committee._

March 21, 1853.

To enable the Committee to arrive at a correct conclusion on this difficult question, I had gone through rather lengthy calculations of the minimum dimensions and the comparative estimated cost of the s.h.i.+ps which would in each case answer the purpose under the several different circ.u.mstances which might be a.s.sumed; and the results of these calculations were laid before the Committee, and the relative advantages and disadvantages of each a.s.sumed case discussed....[143]

After much discussion, and comparing the probable receipts with the estimated expenditure, and allowing fully for interest of capital embarked, I think it appeared to the Committee that as a mere mercantile transaction, and with reference only to the Australian trade, the larger vessel would be the most economical, showing not merely the means of securing the largest return, but involving an actual diminution of annual expenditure....

The Committee were unanimously of opinion that the largest size of the first cla.s.s would be the best, and would in every way answer the objects of the Company.

The dimensions arrived at by calculation for this s.h.i.+p would be in round numbers, 670 feet long, 80 feet beam.

This sized vessel would combine most of the advantages which we seek to obtain. It would carry coal to Diamond Harbour and back to Trincomalee; it would afford room for about 800 separate cabins larger than those now fitted up in packet s.h.i.+ps, with large saloons, capable of accommodating 1,000 or 1,500 first and second-cla.s.s pa.s.sengers; and would carry 3,000 tons weight of cargo, without making any allowance for that increase of speed proportionate to the mere increase of size of which we see every day fresh proofs; the average speed of the s.h.i.+p, with the proposed power of engine and calculated consumption of coal, would be 14 knots at the average, making the pa.s.sage out in 34 days, say 36; but with that increased speed which has been shown to take place with increased dimensions, we may speculate upon the voyage being performed in 30 days.

This same vessel, fitted up for the Australian voyage, and loaded deeper, would carry coals to Australia and back, would take out 3,000 pa.s.sengers easily, and a small amount of cargo only, but could bring back any amount that could be conveniently collected, or if provision were made for taking in 3,000 or 4,000 tons of coal in Australia, that additional amount of cargo might be taken in the pa.s.sage out. The pa.s.sage out to Port Philip should be made easily in 36 days, and home by Cape Horn in the same time.

The Committee having come to the conclusion that this cla.s.s of vessel would best fulfil the several conditions which the circ.u.mstances imposed, I have been engaged in determining the several details consequent upon this selection of size, and have put in hand drawings of the s.h.i.+p, which will enable me to arrive more correctly at the cost, and will enable us to obtain tenders for the construction. These details involve a great deal of study and consideration, and the making of the drawings alone requires some considerable time, so that I do not think much advance can be made under three weeks from the present date, but I will endeavour to expedite the work as much as possible.

Mr. Brunel was authorized to continue his communications with engine-makers and s.h.i.+p-builders, and to invite tenders.

After very detailed and careful calculations of the smallest capacity that would secure the attainment of the objects sought for, the dimensions of the vessel and the power of the engines were finally determined; tenders were received from Mr. Scott Russell, Messrs. Watt and Co., and Messrs. Humphrys and Co. for both sets of engines, and from Mr. Russell for the construction of the hull of the s.h.i.+p and for placing her afloat.

A meeting of the Directors was held on May 18, when Mr. Brunel submitted the various tenders he had received. The Board agreed to adopt his recommendations, and to accept the tenders of Mr. Scott Russell for the s.h.i.+p and paddle engines, and that of Messrs. James Watt and Co. for the screw engines.

The following report, which Mr. Brunel placed before the Directors, gives a detailed account of the steps he had taken to procure the tenders, and the grounds on which he had formed his judgment of them:--

_Report on Tenders._[144]

May 18, 1853.

According to your instructions, I applied to the several parties with whom I had previously been in communication on the subject of the engines and s.h.i.+p, for tenders for their supply. As regards the engines, I drew up a short specification, defining generally what was required, and leaving the parties to make their own designs and propose to me the form of engine they would adopt.

With respect to the s.h.i.+p, where no such variation could be permitted, I have had very detailed drawings and specifications prepared.

Copies of the specifications are annexed.

In defining the power of the engines and boilers, I have, in conformity with my own views and of those of several of the Directors, who have expressed themselves strongly on the subject, required a very full amount of power, without naming the nominal horse-power, which is a very vague mode of defining anything but the cost which by custom is made dependent upon that nominal power; but I have defined dimensions of parts and surface of boilers which will ensure the means of exerting a very large amount of power.

As regards the s.h.i.+p, I have not spared strength of materials, and have required the best workmans.h.i.+p.

The result of this application for designs and tenders is, upon the whole, very satisfactory, although two of the parties from whom I had hoped to have received proposals have not been able to send any....

Mr. Blake, of the firm of Watt and Co., and Mr. J. S. Russell and Mr. Humphrys, have, as I had before reported, devoted much attention to the subject: from these gentlemen I have received distinct well-considered designs of the screw and paddle-engines.

I have been in frequent communication with these gentlemen, and have seen their plans while in progress, and have made my suggestions upon them, and a.s.sisted more or less in maturing them, and at all events in preventing the adoption of any principle or arrangement that I should afterwards object to. Notwithstanding this, the three designs, particularly for the screw engines, are totally dissimilar, and I am placed in the difficulty of having to choose between three totally different plans, each designed by skilful and experienced men, and each possessing many known and acknowledged advantages.

I should also observe that, although I have known the general arrangement which each would adopt, I did not receive the plans or the tenders which I now forward until last evening, and that of Mr.

Humphrys as late as 10 o'clock this morning, and that I have not therefore had time to draw up any very detailed report upon them.

The following are, however, the princ.i.p.al considerations which influence me in the selection which I am disposed to recommend.

It must be borne in mind that the screw engines will be the largest engines that have yet been made. The princ.i.p.al part of the propelling power of the s.h.i.+p will be thrown upon the screw; and upon these engines therefore will mainly depend the performance of the s.h.i.+p, and particularly upon their constant never-failing working, probably for thirty or forty days and nights, must depend the certainty of the s.h.i.+p's performance.[145] Under all these circ.u.mstances, the compactness and stiffness of framing, the greatest possible simplicity of construction, and the fewest possible number of parts, and, finally, the absence of any novelty, however promising, that can introduce any unforeseen difficulties, are conditions which would outweigh in my mind many advantages that might, and I think would, be attained by several arrangements which have been suggested.

All the designs now submitted comply with these conditions to a very considerable extent ... but the extreme simplicity of Mr.

Blake's engine leads me to prefer it.

As regards the paddle engine, I unhesitatingly give the preference to that proposed by Mr. Russell. I believe it to be as simple an arrangement as can be adopted for engines with such a slow motion and so long a stroke as these must have, and the single crank in the centre I consider a great advantage....

As regards a contract for the s.h.i.+p, I have found it more difficult to proceed in the ordinary course. The conditions which we must ensure of quality of workmans.h.i.+p and execution, under close inspection and within reach of one's own supervision, are not easily attained; and, though as a matter of course readily promised and undertaken by all s.h.i.+p-builders, they are rarely secured. It is essential also that the s.h.i.+p should be built where the engines can be readily fixed on board before launching, and in a yard which can be devoted to the purposes of the s.h.i.+p, and whence the launching can be effected with the engines and boilers on board.

All these are conditions not easily secured. I have been in communication with one or two parties, and the result is a tender from Mr. J. Scott Russell, which I enclose, and which has in fact been framed upon my calculations. Owing to the recent rise in iron it is somewhat, but not materially, above the amount at which I had originally estimated the vessels; but the tender, founded upon the supposition of two such vessels being ultimately ordered, is as nearly as may be the same as my original estimate, and upon the whole I consider the tenders both for engines and s.h.i.+ps very satisfactory and confirming fully our previous calculations.

These tenders do not include, in the case of the engines, either the screw itself or the paddle wheels, nor, in the case of the vessel, the cabin fittings, masts, and rigging, boats, or stores. I should estimate these roughly at 50,000_l._ more,--at least such an allowance ought to be ample; but these details will require a great deal of consideration, and could not be included in the original contracts; while at the same time they can mostly be better and more economically supplied by compet.i.tion or by arrangement with the special makers of the respective articles....

During the next six months Mr. Brunel was engaged in preparing the formal contracts and specifications. These doc.u.ments were settled with much care, and after frequent communications with the contractors, who consented to the insertion of clauses which gave the full control and supervision over every part of the work to the Engineer, with very large powers of interpretation. They required, however, that, should Mr.

Brunel cease to act as Engineer, any disputed point should be settled by arbitration, and not by his successor.

Besides the delay occasioned by the magnitude and novelty of the undertaking, there were other difficulties which helped to postpone the commencement of the works. The Directors were unable, under their charter, to enter into any contracts until a certain amount of their capital was actually paid up; and, as several shareholders had retired when the change of plans was determined upon, it was no easy work to get the shares taken. That this was eventually accomplished was due mainly to the exertions of Mr. Brunel and Mr. Charles Geach, one of the Directors.[146] 'Could I have foreseen,' Mr. Brunel writes, 'the work I have had to go through, I would never have entered upon it; but I never flinch when I have once begun, and do it we will.'

Several times they nearly broke down, but at length the contracts were signed, and on the same day, December 22, Mr. Brunel gave the formal notice to the contractors to proceed with the works. 'After two years'

exertions (he wrote), 'we are set going, the contracts entered into, and the work commenced.'

_Extracts from Mr. Brunel's Memoranda_, A.D. 1852-1853.