The life of Isambard Kingdom Brunel, Civil Engineer
CHAPTER XI.
_STEAM NAVIGATION--THE ‘GREAT EASTERN’ STEAM-SHIP, FROM THE COMMENCEMENT OF THE UNDERTAKING TO THE LAUNCH._
A.D. 1851--1857. ÆTATIS 46--52.
INTRODUCTORY OBSERVATIONS--THE AUSTRALIAN STEAM NAVIGATION COMPANY--STATEMENT OF MR. BRUNEL’S PROJECT OF A LINE OF LARGE SHIPS (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 SHIP (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 SHIP 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 SHIP--MEMORANDUM ON THE MANAGEMENT OF THE GREAT SHIP (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-ships.[139] The ‘Great Eastern’ is but the result of the application, under different circumstances, 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-ships. In that year he was consulted by the Directors of the Australian Mail Company upon the class 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 ships 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 ships 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 ship’ 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 passengers 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 ship 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 establishing an additional line of steam communication by the overland route, for the conveyance of mails, passengers, &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 ships of the present dimensions would build and work ships to carry in the year double the number of passengers, 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 passage 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 passage, and then only by being completely filled with coals and leaving no room for passengers or cargo. Simply by building a ship of the size necessary to take the coal, over and above the accommodation required for a due number of passengers and a reasonable quantity of cargo, the passage 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 ship 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 circumstances 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 assisted 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 ships 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 passengers as offer. Thus the capital embarked in the one vessel is not so great in proportion to the tonnage space 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 assisted 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 Ship._
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 ship. 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 ship, 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 assumed difficulties of construction, or regard to assumed 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 assistance 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 midship 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 assumed 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 assumed 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 quantity and weight of material in the ship, which last consideration is very greatly in favour of breadth of beam; for I think you will find that the quantity of iron in two ships 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 ships 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 circumstances of our case, all this certainly can, I think, be assured, but it can be assured only by proceeding with the caution and the decision which the circumstances 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 assistance of those most competent to afford the required information. I have called in to my assistance 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.
With respect to the form and construction of the vessel itself, nobody 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 assistance I think we may rely upon the certainty of being able to design and to execute all that is best in the mechanical and ship-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 assistance, settled preliminarily some of the principal points of detail. What I should propose to the Directors now is, that with that assistance I should proceed to prepare in detail the design of the ship, 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 ships, 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 principal 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 circumstances 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 23½ 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 ship 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 ships, and upon further consideration of these three, and under the circumstances, 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 ship and engines for your consideration.
Efforts were made to induce the public to assist 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 ships which would in each case answer the purpose under the several different circumstances which might be assumed; and the results of these calculations were laid before the Committee, and the relative advantages and disadvantages of each assumed 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 class would be the best, and would in every way answer the objects of the Company.
The dimensions arrived at by calculation for this ship 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 ships, with large saloons, capable of accommodating 1,000 or 1,500 first and second-class passengers; 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 ship, with the proposed power of engine and calculated consumption of coal, would be 14 knots at the average, making the passage out in 34½ 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 passengers 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 passage out. The passage 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 class of vessel would best fulfil the several conditions which the circumstances imposed, I have been engaged in determining the several details consequent upon this selection of size, and have put in hand drawings of the ship, 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 ship-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 ship 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 ship 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 ship, 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 ship, 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 ship, I have not spared strength of materials, and have required the best workmanship.
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 assisted 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 principal 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 principal part of the propelling power of the ship will be thrown upon the screw; and upon these engines therefore will mainly depend the performance of the ship, and particularly upon their constant never-failing working, probably for thirty or forty days and nights, must depend the certainty of the ship’s performance.[145] Under all these circumstances, 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 ship, I have found it more difficult to proceed in the ordinary course. The conditions which we must ensure of quality of workmanship 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 ship-builders, they are rarely secured. It is essential also that the ship 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 ship, 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 ships 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 competition 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 documents 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.
_July 11, 1852._--The dimensions I commenced with in March last, of 650 × 70 × 30 appear after all to be not far wrong, according to present views. I make them now 700 × 70 × 24 about; but much depends upon the last dimension, the draught. If another foot or two can be safely taken it will be of great advantage.... With this size of vessel, having a midship section of about 1,800, and a length of 700, I assume a nominal horse-power of about 2,500. The first question of importance is, in what proportion shall this be divided between the screw and paddles?... My present impression is to halve the power between the two.
In both the engines every known means must be adopted to secure efficiency:--1, An excess of boiler power; 2, expansion permanently, say at ⅓; 3, steam of not less pressure than 20 lbs., and I should prefer 25 lbs.; 4, that cylinders, particularly top and bottom, slide chest, and steam pipes, be all jacketed, and the jacket supplied with steam from an auxiliary boiler of at least 10 lbs. more pressure than that of main boilers; and it would be very desirable to make some experiments to determine whether it is not worth having a heating apparatus to heat the steam immediately before it enters the cylinders.[147]
_July 17._--After a long conference with Mr. Field, I continue of the opinion that it would be well to apply about three-fifths of the power to the screw and two-fifths to the paddles, and probably, as the vessel gets light, diminishing a little the expenditure of power on the paddles, and keeping up the full power on the screw. Mr. Field is not in favour of increasing the pressure of steam beyond 12 lbs. or 15 lbs., on the ground that all the mechanical difficulties increase rapidly without a corresponding advantage, particularly where size and weight are not so important. There seems much truth in this.... The possible advantages of a slight increase are not sufficient to justify the risk of the possible new difficulties in a work on so large a scale. Nothing uncertain must be risked. These arguments do not apply to the jacketing and heating, which Mr. Field also deprecated, or rather discouraged, simply on the ground of the trouble and difficulty of effecting it, but he admitted that all experience went to show the advantages of it; and as to the difficulties, which I could not see, they involve no other risk than that of being useless: they cannot do mischief. The heating of the top and bottom of the cylinders, I think, must be particularly important in a short-stroked engine working expansively. In a cylinder of 80 inches diameter and 40 inches stroke, having regard to the _time_ of contact, the area of the bottom will be nearly equal in effect to the surface of the cylinder.
_July 19._--After much consideration, I think I feel satisfied that the best construction will be to have strong bulkheads every 30 feet or thereabouts, this distance being dependent on what is required for one set of boilers and its stock of coals; these bulkheads being carried right up wherever practicable--I think every alternate one may be--and then place the main ribs of the ship, and even at least two main deck beams, _longitudinal_ instead of _transverse_.
_February 2, 1853._--Several drafts of ships have been made and much consideration given to the subject, and frequent discussions with various parties. The result of all is that my present views are as follows:--
The ship, all iron, double bottom, and sides up to water line, with ribs longitudinal like the Britannia tube. I have not been able to devise any good mode of determining the relative amount of friction of a copper and an iron surface; and, although I believe in copper, it would not do to act on mere belief. I therefore at present settle iron, the surface being carefully made smooth. Doubts have come across me also as to whether with a very long surface the difference between the smoothness will so much affect the total resistance. Is not a film of water, after a certain distance, carried with the body? and, if so, its greater or less roughness, if not producing currents, is almost unimportant. Would there be any difference in the resistance of a fine file or a rough one drawn through tallow, if they both covered themselves with grease? Is there any similarity? As to size, if we are to go round the world,[148] I do not think we can do with less than--length, 730; beam, 85; draught deep, 34; and I assume a nominal horse-power of engines equal to 1¼ of the sectional area at 30 feet; but, taking consumption as a better measure, and assuming that every possible economy is practised, and every refinement introduced that can produce economy, I shall assume 7½ lbs. per hour per nominal horse-power, or say 0·08 ton per day per horse-power; and as I assume the horse-power to be 1¼ sectional area, it makes the consumption =0·1 ton per day per foot of sectional area. And this is a very large allowance and ought to ensure a very high speed. In order to effect the utmost economy, I should work up to 20 lbs. steam (calling it 16 lbs.), cutting off certainly at ⅓ the stroke, and adopting every precaution to keep the steam hot and the condenser cool. The latter depends, I believe, solely upon the perfect dispersion of the injection water, so that the condensation of the steam may take place suddenly, otherwise the same amount of water may condense the steam _in time_, the same amount of heat be given off, the same quantity of injection water used, and yet the condenser be always full of steam at a good pressure. It might be well worth the experiment to try the effect of a large injection at the moment of the exhaust port being opened; but above all things I believe the heating of the steam to be important; and for this purpose I should jacket the steam pipes and cylinders top and bottom, and heat with high pressure steam, say at 60 lbs.--I have increased this pressure the more I think of it; 60 lbs. would be above 300 degrees, and 20 lbs. not quite 260 degrees; therefore there would be a full 40 degrees of surplus to ensure the temperature. I have a great tendency to believe in the advantage of further heating even, which might be done by a Perkins’ arrangement of hot water; but possibly the new conditions, as regards oiling, &c., might involve difficulties not desirable to introduce in this case. In the boilers it will also be necessary to adopt every refinement which has been found really to answer, although not always adopted; above all, every means of keeping them clean--scum pans, and Field’s exchanging apparatus. But what would be even more effectual would be some easy means of removing a whole bundle of tubes and replacing them by clean ones; and surely this would not be difficult, the tubes being large and with plenty of space, so that a man could pass his arm between. A rather important addition to boilers would also be a means of blowing off without noise. Several modes would seem to be possible, but whatever plan is adopted, it should be one which is completely self-acting, and perfectly effectual when used suddenly and without any preparation, and at a moment of confusion and alarm. Blowing through a wire gauze pipe would probably be as likely a way as any.[149]
The more consideration I give to the subject the more disposed I am to adopt oscillating engines for both screw and paddles. The extreme simplicity and small number of parts, and compactness, and the direct action of every resistance to the force which it is wanted to resist, seem to leave nothing to be desired, and would seem to make it a better and more mechanical arrangement of a cylinder and crank than any other, quite independently of the object for which it was originally designed, which was simply ‘stumpiness.’
_February 21._--The original line (to Calcutta) seems likely, after all, as usual with most original ideas, to be the best; at all events, so good that the vessel must be built to be able to go there. The dimensions best fitted for this would seem to be--length, 700 feet; beam, 85 feet; depth of hold, 58 feet; screw, 24 feet; paddle 60 feet. If arranged for Calcutta, we must arrive there on an even keel, and therefore, to maintain the most equal level for the paddles, they must be kept well forward, and the change principally at the stern. Engines indicated horse-power 8,000; steam at 25 lbs.; auxiliary steam at 60 lbs.
The ship to be lighted with gas, to be thoroughly ventilated by mechanical means, having large air trunks, with small pipes and valves to each cabin, with the means of warming this air in cold latitudes and seasons, and cooling it in the more frequent cases of hot climates. The ship must be steered from the forecastle, whence a perfect look-out must be kept with fixed telescope, &c., and speaking pipes and bells to the engine rooms.
_March_ 14.--At a meeting of the Committee, held this evening here, the several costs and qualities of four different sizes of ships, of which all the calculations had been made by me, namely:--
No. Length Breadth Mid. Sec. Draught 1 663 79·9 1,646 24 2 634 76·39 1,640 25 3 609 73·5 1,639 26 4 730 87 2,090 28
were discussed, and the No. 1 determined upon as the best under all the circumstances. I should propose, therefore, to make the dimensions of No. 1:--length, 680 feet; beam, 81 feet, to be swelled to 83 feet; extreme draught, 30 feet; mean, 24 feet; daily consumption, say 200 tons.
This ship can carry her coal to Calcutta, and arrive and leave with only 21 feet 6 inches draught, having 9 days’ coal and 3,000 tons cargo; or she could first go to Australia and back, without or with very little cargo out, and consequently would take out as much cargo as you might choose to send coal for her to Australia....
These dimensions are worked out in the design No. 5 (April 9, 1853), but they would be better for a slight increase, if the 83 feet were made 85 feet, and the 680 feet were made 700. We should have an increase in capacity of 83 × 680=56,440 to 85 × 700=59,500, or 6 per cent. of displacement. This would bring the displacement at 32 feet draught up to 31,250 tons.
_March_ 22.--Settled the various dimensions of scantlings with S. Russell to enable him to direct drawings of all details to be got out.
_April_ 28.--We are now seeking tenders for engines and ship of the following dimensions:--Length, 680 feet; beam, 83 feet; mean draught, about 25 feet; screw engine, indicated horse-power 4,000; nominal horse-power, 1,600; paddle, indicated horse-power, 2,600; nominal horse-power, 1,000; to work with steam 15 lbs. to 25 lbs.; speed of screw, 45 to 55 revolutions; paddle, 10 to 12.
Among the details of improvements still to be considered are the receiving through measures the coal from the bunkers, and running it on tramways and waggons to the front of the fires, thus at the same time measuring out accurately the hourly consumption, and saving labour; but a still more important object, the use of clean water--that is, using the same water over again--is well worth considering; and it is well worth the experiment, whether cooling down the water of condensation to use again is not in fact the easiest way. With an unlimited supply of cooling water this ought to be easy.
_August 7._--Memoranda for engines.--Very sensitive governors to be applied to both engines to prevent running away.
_November 18._--It is curious that the above should be the last memorandum, as I now open the book to make the same in consequence of the accident to the ‘Agamemnon.’[150]
There can be no reason why a sensitive governor should not act in less than one revolution of the crank, and act upon a tumbler which should shut off instantly the expansion valve. There should be two such governors, one to each end of the crank shaft, and they should work direct from a spur wheel from the shaft without any intermediate shafting, to give elasticity, or to risk breaking. (Query, hydraulic governors?)
The auxiliary engine and boiler to be at least 20 feet from bottom, and, better still, above load water line, or so boxed as to be out of reach of water; so that if the ship grounded and filled, this engine would remain serviceable for pumping or anything else.
The history of the ‘Great Eastern’ has now been traced up to the date of the contracts for the construction of the ship and her engines.
The following selections from Mr. Brunel’s memoranda illustrate the progress of the design during the early months of the year 1854:--
_February 25, 1854._--The details of construction, both of engines and ship, involve an immense amount of thought and labour. I have devoted a great deal of time to it already, and yet even the preliminary details either of engines or ship are far from being satisfactorily settled. I have no record of the many consultations hitherto held on the subject, but shall hope to keep one hereafter. On the 6th inst., some of the drawings of the ship and of parts of the engines, having been several times revised and altered, being ready, I spent the greater part of the day at Millwall[151] in going again into them, and settled some parts, such as the dimensions, &c., of cranks, and bearings, general form of engine frame, and some of the general principles of framing and plating of the ship. Some other consultations have been held, and again to-day (February 26) I have spent some hours at Millwall.... Discussed the details of a midship section, the drawings of which were in a forward state; directed that the cabins should positively be made 6 feet 6 inches each in the clear, and the bulkheads made subordinate to this; found that it could be done without difficulty, and without causing any mechanical objections in construction. I am anxious to have some approximate estimates of weights.
It is evident that large weights may most easily be wasted or saved by a careless or close consideration of the best application of iron in every single detail. I found, for instance, an unnecessary introduction of a filling piece or strip, such as is frequently used in ship-building to avoid bending to angle irons; made a slight alteration in the disposition of the plates that rendered this unnecessary; found that we thus saved 40 tons weight of iron, or say 1,200_l._ of money in first cost, and 40 tons of cargo freight--at least 3,000_l._ a year. The principle of construction of the ship is in fact entirely new, if merely from the rule which I have laid down, and shall rigidly preserve, that no materials shall be employed on any part except at the place, and in the direction, and in the proportion, in which it is required, and can be usefully employed for the strength of the ship, and none merely for the purpose of facilitating the framing and first construction.
In the present construction of iron ships the plates are not proportioned to the strength required at different parts, and nearly 20 per cent, of the total weight is expended in angle irons or frames, which may be useful or convenient in the mere putting together of the whole as a great box, but is almost useless, or very much misapplied, in affecting the strength of the structure as a ship.
All this misconstruction I forbid, and the consequence is that every part has to be considered and designed as if an iron ship had never before been built; indeed I believe we should get on much quicker if we had no previous habits and prejudices on the subject.
_March 3._--Mr. Blake [_of the firm of Messrs. James Watt and Co._], called, and went fully into the general drawings which he brought. On the necessity of large surfaces he quite concurred with me. The extent to which such a general principle should be carried is of course very difficult to determine; my idea is that it has never yet been approached....
_March 10._--Engaged all the afternoon at Millwall.... Settled and signed the drawings of crank and piston rods. Went into many details of ship....
The extracts from Mr. Brunel’s correspondence which follow, have been selected as containing a definition in his own words of the position he held as Engineer to the Company by which the great ship was built.
_Letter to the Secretary of the Eastern Steam Navigation Company._
[This letter was written in consequence of a resolution of the Directors, asking Mr. Brunel to recommend them a resident engineer, in order that constant supervision might be exercised over the works, and frequent reports made to the Board.
The Directors rescinded their resolution; but this letter is inserted as showing, in clear and forcible language, Mr. Brunel’s view of the nature of his duties and responsibilities, and as laying down what in his opinion ought to be the relations between the Directors of a Company and their Engineer.]
August 16, 1854.
...It surely cannot be necessary to remind the Directors that the very unusual stake which as a professional man I have been willing, perhaps imprudently, to risk on the success of this project--I mean stake of professional character, not mere pecuniary risk--must secure a much greater amount of attention to any step, and supervision of any detail on my part, than any ordinary professional engagement would obtain; the heavy responsibility of having induced more than half of the present Directors of the Company to join, and the equally heavy responsibility towards the holders of nearly half of the capital, must ensure on my part an amount of anxious and constant attention to the whole business of the Company which is rarely given by a professional man to any one subject, and, as it seems to me, ought to command a proportionate degree of confidence, or rather command entire confidence, in me, if any at all, for in such a case there can hardly be any medium. The fact is, that I never embarked in any one thing to which I have so entirely devoted myself, and to which I have devoted so much time, thought, and labour, on the success of which I have staked so much reputation, and to which I have so largely committed myself and those who were disposed to place faith in me; nor was I ever engaged in a work which from its nature required for its conduct and success that it should be entrusted so entirely to my individual management and control....
The Directors have a right to expect, and will ever receive, from me the fullest information and the most unreserved communication upon all points as they arise, as from one who feels the responsibility of being their sole professional adviser in a very important and serious business, in which we are all embarked, and all deeply interested; but I cannot act under any supervision, or form part of any system which recognises any other adviser than myself, or any other source of information than mine, on any question connected with the construction or mode of carrying out practically this great project, on which I have staked my character; nor could I continue to act if it could be assumed for a moment that the work required to be looked after by a Director, or by anybody but myself or those employed directly by me and for me personally for that purpose.
If any doubt ever arises on these points I must cease to be responsible, and cease to act.
_Letter to the Secretary of the Eastern Steam Navigation Company._
[In explanation of the following letter it need only be stated that an elaborate article on the great ship appeared in one of the London newspapers of November 1854. Mr. Brunel’s name was only once mentioned throughout the whole of it, and in these words: ‘Mr. Brunel, the Engineer of the Eastern Steam Navigation Company, approved of the project, and Mr. Scott Russell undertook to carry out the design.’]
November 16, 1854.
Since I wrote to you I have taken the trouble to read through the long article in the----, and am much annoyed by it. I have always made it a rule, which I have found by some years’ experience a safe and profitable one, to have nothing to do with newspaper articles; but then, if on the one hand the works I have been connected with have rarely been puffed (never by me), they have also been rarely affected by misstatements; as such notices, when not inserted by interested parties, are always slight and unauthentic, and drop without producing any effect. This article in the----, however, bears rather evidently a stamp of authority, or at least it professes to give an amount of detail which could only be obtained from ourselves; and if, as I think is the case, copies of it have been circulated by us, it may acquire the character of being an authorized statement; and, as such, I am individually much annoyed by a great deal that is in it, and by the omission of much that might with propriety have been introduced.
What is constantly repeated or implied, and remains uncontradicted, is at last received almost unconsciously as fact even by those who have the means of knowing it to be incorrect, if they thought about it; and, although from system I have never interfered with newspaper statements, it has not been from any affected or real indifference to public opinion, perhaps it was more from pride than modesty, and therefore I am by no means indifferent to a statement which would lead the public, and perhaps by degrees our own friends, to forget the origin of our present scheme, and to believe that I, happening at the time to be the consulting Engineer of this Company, which I was not, and having had no peculiar connection with previous successful improvements in steam navigation, allowed them to adopt some plan suggested by others, who I suspect, if even such were the case, would never appear to share with me the responsibility if any failure should result. Of this certainly I have no fear, but at the same time I am desirous of something more than mere immunity from blame.
I not only read this article once, but I was so struck by the marked care shown in depreciating those efforts which I had successfully made in advancing steam navigation, and mainly on the strength of which no doubt I originally obtained the confidence of the Directors, which induced them to enter upon our present bold undertaking, that I read the paper a second time, and for the very reason that I have for so many years shunned public writings, namely, to escape misstatements, I feel compelled on the present occasion to take some steps publicly to correct those erroneous impressions, which must be created by a document having the appearance of emanating from ourselves....
The objectionable points that I refer to evidently did not strike you, and that is a strong proof how easily incorrect impressions insinuate themselves unawares; but I feel strongly that a judicious friend would not have failed to do justice to the spirited merchants of Bristol, who, in spite of the strongest condemnation of the plan by the highest authorities, and the ridicule of others, persevered in building and starting the first transatlantic steamer. The circumstances as regards the ‘Sirius’ are coloured so as to be quite incorrect; and the same friendly hand would not have thrown ridicule, and that by a positive false statement, upon that which he at the same time admits to have been the means of almost introducing two of the greatest improvements in steam navigation. A writer wishing success to our enterprise would not have omitted to mention that I had a claim to public confidence on this occasion, for the reason that I was at least the principal adviser in those previously successful attempts.
And lastly, I cannot allow it to be stated, apparently on authority, while I have the whole heavy responsibility of its success resting on my shoulders, that I am a mere passive approver of the project of another, which in fact originated solely with me, and has been worked out by me at great cost of labour and thought devoted to it now for not less than three years....
The works had been commenced in the spring of the year 1854, and the progress of the ship towards completion was eagerly watched, both by scientific men and by the general public.
The newspapers and periodicals of the day frequently contained descriptions of the work, and statements of the anticipated performances of the ship, often very much exaggerated. The writers seem to have been quite at a loss how to convey to their readers any idea of her size, and they generally attempted to do so by comparing her dimensions with those of some of the well-known streets and squares in London.[152]
In the beginning of the year 1855, the longitudinal and transverse bulkheads, which formed the main framework of the ship, were completed for nearly 400 feet of the centre portion, and the plating was being fixed in place.
As the general design was now settled, it was thought that the time had arrived when it would be desirable for Mr. Brunel to describe at some length the nature of the undertaking, and the manner in which it was being carried out.
_Report to the Directors of the Eastern Steam Navigation Company._
[This Report was published at the time and excited much attention.[153] The paragraphs which describe the arrangements proposed for launching the ship have been omitted, as they will more conveniently be inserted in the following chapter.]
February 5, 1855.
* * * * *
Although the simple description of the present state of the works of the ship and engines, and of what has been done during the last six months, may be summed up in a few words, I shall, in compliance with the request of the Directors, embody in this the substance of the several other reports which I have from time to time made to the Court of Directors during this half year, and take this opportunity of laying before the proprietors the fullest information upon our plans and proceedings. In doing this it may be difficult to avoid some appearance of repetition of statements previously made; but I have thought it better, even at the risk of this, to refer to the objects we have had in view, and explain fully the nature of the works we have undertaken, and the manner in which we are carrying them out.
The construction of the vessel is the portion of our work which, without being actually novel, involved in all its details the greatest amount of special consideration and contrivance.
The unusual dimensions, the general form and the mode of construction of all the parts involved by these dimensions, the necessity of studying each part in detail, so as to obtain, by judicious mode of construction alone, the greatest amount of strength with the minimum amount of material; all these circumstances, and particularly the last, have rendered necessary a very large, though unseen, amount of labour in the preliminary plans and stages of the work; and, although I had for nearly two years before the contracts were entered into, devoted a great deal of time and thought to the subject, yet of course until the exact size of the vessel, and the general plans of the Company, had been finally determined upon none of these matters could be entered into in detail. Much time has consequently been required to mature and prepare these plans; and as I have made it a rule from the first that no part of the work should be commenced until it had been specially considered and determined upon, and working drawings in full detail prepared, and, after due deliberation, formally settled and signed, the work did not make at the onset that display of progress which might have been made, if less regard had been paid to establishing a good system which would prevent delays hereafter, and ensure a more perfect and satisfactory result. I am not prepared to say that the work is in that state of progress which will ensure its completion within the period fixed in the contract; but I am quite certain that if we had proceeded with less system we should have considerably delayed the final completion.
I shall now refer to a few of the principal peculiarities in the construction of the ship.
In the preparation of the detailed plans, I have carried out fully those principles which I originally described as leading features of the construction.
The whole of the vessel is divided transversely into ten separate perfectly water-tight compartments by bulkheads carried up to the upper-deck, and consequently far above the deepest water lines, even if the ship were water-logged, so far as such a ship could be; and these are not nominal divisions, but complete substantial bulkheads, water-tight, and of strength sufficient to bear the pressure of the water, should a compartment be even filled with water; so that if the ship were supposed to be cut in two, the separate portions would float; and no damage, however great, to the ship’s bottom, in one or even two of these compartments would endanger the floating of the whole, or even damage the cargo in the rest of the ship, or above the main-decks of the compartment in question, and all damageable cargo would be stowed above that deck. Besides these principal bulkheads there is in each compartment a second intermediate bulkhead, forming a coal bunker, and carried up to the main-deck, which can, on an emergency, also be closed. There are no openings under the deep-water line through the principal bulkheads, except one continuous gallery or pipe near the water line, through which the steam pipes pass, and which will be so constructed as to remain closed, the opening being the exception, and the closing again being easy, and the height being such that, under the most improbable circumstances of damage to the ship, ample time would be afforded to close it leisurely, and to make it perfectly water-tight. I have also adopted the system, to be followed rigidly and without exception, of making no openings whatever--even by pipes and cocks--through the ship’s bottom, or through the inner skin below the load water line, and I attach much importance to this system.
In the majority of cases in which steamboats are compelled to put into port from failure of bilge-pumps and other really trifling defects, no such serious consequence would have resulted, but from the difficulty and almost impossibility of remedying at sea any defects in the numerous pipes and openings now carried through the ship’s bottom, wherever convenient, and without much regard to the danger of doing so.
I have found no great difficulty in carrying out this system completely, and the advantages, both as regards safety and the facility of remedying defects without delaying the ship on her voyage, must be obvious.
Independently of the security attained by the perfect division of the ship into really water-tight compartments of a sufficient number, so that the entire filling of one or even two of them will not endanger the buoyancy of the whole, the chances of any such damage as can cause the filling of one of them are greatly diminished by the mode adopted in the construction of the ship’s bottom. The whole of the vessel (except the extreme stem and stern, the whole buoyancy of which is comparatively unimportant from the fineness of the lines), up to a height considerably above the deepest water line, is formed with a double skin, with an intervening space of about three feet. This arrangement resulted originally from the system of construction I adopted, in which the bulkheads, placed at intervals of twenty feet, form the main transverse frames or ribs of the ship, and in the intermediate space the material is disposed longitudinally in webs connecting the two skins, giving to the whole much greater strength with the same amount of material; but one of the most important results has been the great increased security attained, as the outer skin may be torn or rent against a rock without causing the ship to leak.
The space between these two skins is thus divided, by the longitudinal beams or webs and the principal bulkheads, into some fifty separate water-tight compartments, any one or more of which may be allowed to fill without materially affecting the immersion of the ship.
Besides the main transverse bulkheads, at about 60 feet intervals, there are two longitudinal bulkheads of iron running fore and aft, at about 40 feet in width, adding greatly to the strength of the whole, and forming, with the transverse bulkheads, being all carried up to the upper deck, fire-proof party walls, cutting up the whole into so many separate parts, that any danger from fire may be almost entirely prevented.
The transverse bulkheads being perfect, there being only one door--and that of iron--in each, at one of the upper decks, all currents of air or means of communicating fire may be completely cut off; and with an additional precaution, which I will refer to afterwards, besides the most ample means of supplying water, I believe that all possibility of danger from fire may be completely prevented.
All these principles of construction being kept in view, the details of construction--that is, the arrangement and due apportionment of the strength and sizes of all the plates, and the mode of fastening them--having been determined separately, the plates have been made at once of the required dimensions, and the work has proceeded systematically. This system is the most important, as securing not only good work, but affecting, to a much greater extent than might at first be supposed, the total weight of the ship; which, although the terms of the contract protect the Company against any excess of expenditure beyond a certain fixed sum, is yet of the greatest importance, as will be easily understood when I mention the fact that several merely trifling alterations in the modes of arranging the plates and other details have caused an economy of 20 to 50 tons each, and that the vessel may thus be made capable of carrying 200 to 300 tons more of coal, cargo, or provisions; or iron to the same amount may be usefully applied to strengthen other parts or effect useful additions.
The details of the engines have all been settled; and the principal parts, as already stated, are in an advanced state of completion.
In considering the plans of those engines, the largest that have yet been manufactured, I have endeavoured to ascertain what may be termed the weak points of the best engines hitherto constructed by the same or by other makers--those points in which experience has pointed out deficiencies--and to provide fully against similar defects in our case.
Before commencing the boilers, I have taken every means in my power of profiting by the experience of others, and have collected all the evidence and opinions as to the precise form and proportions which have been found most efficient; and particularly such as have been found best suited to the combustion of anthracite coal. A very great difference is found to exist in the useful and economical results of boilers, even of good manufacture. Some are noted for the power of producing rapidly abundance of steam, at the cost of great consumption of fuel; others have the opposite qualities, and some combine successfully both those qualities which are desirable. It might have been supposed that all points of such a simple subject would have been long since settled, and that no boiler would be made inferior to the best. Such is not, however, the case; and although the differences of construction are in themselves slight, the difference of result is often considerable.
I have taken some pains to satisfy myself on these points, and have endeavoured to select and to copy the most successful boilers; and in order to remove all doubts as to their fitness for the use of anthracite, I have made an experimental boiler, and, after numerous trials, determined upon the form and dimensions to be adopted.
In the consideration of these details, as indeed on all other points affecting the success of this undertaking, I have not hesitated to consult everybody whose opinions I considered valuable, and to bring the result of their opinions in aid of my own and the manufacturer’s experience.
I have only to add, that after giving much consideration to the question of the diameter of the paddle-wheels and screw, I have determined them sufficiently for fixing the position of the shafts, and am now engaged in considering the best form and construction of the propeller itself, and also the construction of the stern-frame and rudder of the ship.
The position of the paddle-shaft, and the diameter of the paddles, have been questions of some difficulty. It being necessary to provide for a considerable variation in the draught of water, though not proportionably so great as with many existing large steamers, and to balance well the relative advantages of securing the highest average speed, at all the various draughts, or the highest speed at a light draught, and to combine as far as possible the two, so that the vessel may be as well adapted to perform comparatively short and very quick passages to ports not affording a great draught of water, as long voyages, heavily laden, at a more moderate maximum, but still a large average rate of speed. Although the full advantage of the great capacity of the vessel for carrying coal for long voyages would not be felt in a voyage, for instance, to New York, or in other short voyages, yet, unquestionably, she would exceed all other vessels in speed and extent of accommodation; and if it should be found desirable to make such voyages, your vessels ought to be able to command almost a monopoly by their superior capabilities, and I have therefore endeavoured so to place the paddle-shaft, and so to construct the wheels, that they may be adapted to the convenient application of the full power of the engine at a light draught of water and at very high speed.
As regards the screw, the same points have to be considered, and a choice made amongst the various forms and proportions more or less successfully adopted at the present time. I have always found the reports made upon the results of various forms of screws and propellers, and the performance of different vessels, so little to be depended upon, even when apparently made in good faith, and the results obtained from good authority, that I have been long since compelled to adopt no conclusion, unless from results witnessed by myself or by persons observing for me. I have for some time past availed myself of every opportunity that offered of observing and obtaining something like accurate results upon the various points affecting immersion of paddles or screw, and I am engaged in considering those results.
I have referred to the subject of protection from fire; it is one of considerable importance, and I have some hopes that a process, which has been recently patented by Lieutenant Jackson, may be successfully applied to rendering wood uninflammable. Some door panels have been already experimented upon with results which have induced me to pursue the experiments, and I am about to try the comparative inflammability of various qualities of wood, both prepared and unprepared; and if we can succeed in preventing the wood producing a flame, and thus communicating the fire; with the numerous metallic subdivisions we shall have in the ship, the spreading of fire, even from cargo or furniture, would become impossible. I am also engaged in determining the character and extent of mast and sail to be carried, as provision must now be made in the construction of the ship for receiving the masts.
The Directors are aware that I have been in communication with Professor Airy as to the instruments which may be used in such a ship, to ensure more accurate and frequent observations, and as to the nature of these observations; an enquiry into which he has entered with that liberality and desire to assist all improvements, in navigation especially, for which he is so well known. Several new instruments are now making for trials.
Sir W. Snow Harris has promised to turn his attention to the subject of the lightning conductors; and as soon as the iron work is a little more advanced, and while the form and position of all the principal masses are visible, the subject of local attraction and the adjustment of the compasses will be considered by those most competent to advise; and I am not without hope that the means of correction may be rendered much more certain and perfect than usual. I mention these, as some of the numerous points which require and are receiving attention.
In the last paragraph but one of this report Mr. Brunel mentions that he proposed to adopt a system for obtaining continuous observations in order to determine the position of the ship.[154]
His first letter to the Astronomer Royal, which is dated as early as October 1852, explains the object with which he began his investigations:--
October 5, 1852.
You may possibly have heard of a project in which I am engaged, of building some _very large_ steamboats.... Among the several requirements, which it appears to me are involved in such a large project, is one in which I hope for your advice and assistance, and I trust you will consider the subject worthy of your attention. In such a voyage, where so much depends upon perfect navigation, and with such a capital at stake, no means can be too perfect and no expense or trouble must be spared to ensure the constant determination, with the greatest attainable accuracy, of the ship’s position and course. The determination of her speed, the effect of winds and currents, and the variation of her compasses, together with meteorological observations, are all involved in this; and I propose to have an observatory and establishment of observers, whose duty it will be to be constantly engaged, day and night, at any moment when anything can be visible in the heavens, in taking such observations as will determine more or less accurately, according to the nature of the observations that the state of the weather or other circumstances may admit of, the several points to be ascertained. Now, the questions to be determined are, what is the nature of the various observations that can best be made under all the different, and the favourable and unfavourable circumstances that may daily arise? what the instruments required, and what the character and extent of the staff of observers required; and even whether any, and if any what, new tables might be useful for such a purpose? The primary object being to be _constantly_ determining either correctly or approximately the ship’s true position, and in like manner _constantly_ checking the compasses and giving her true course. I will not unnecessarily expose my ignorance in such matters by stating what I have assumed to be practicable. I will only remind you that experience proves that in a vessel of such size there will be great steadiness of motion, and therefore unusual facilities for accurate observation.
Mr. Airy entered very warmly into the subject, as did also Professor Piazzi Smyth, the Astronomer Royal for Scotland; and a long and interesting correspondence passed between them and Mr. Brunel. Experiments were conducted, principally with the view of obtaining a stand for astronomical instruments by means of the contrivance known as the gyroscope, the principle of which had been already adopted by Mr. Brunel in a level designed by him in 1829.
In connection with the observers’ department, Mr. Brunel paid much attention to designs of sounding apparatus and means for accurately measuring the speed of the ship. He also intended to have a stream of surface water constantly pumped up through the observers’ cabin, which should, by its change of temperature, immediately indicate the presence of icebergs, instead of the plan of an occasional bucketful being hauled up on to the deck according to the humour of the officer of the watch.
Mr. Brunel made a very curious contrivance for enabling the man on the look-out to keep his eyes open in a gale of wind. This consisted of two sets of vertical plates of tin placed one behind another, diverging from the direction of the wind, with a clear wide passage between the two sets of plates. The wind, entering at the end of the apparatus, became separated by the first two inclined plates, and the residue that passed on in the direct line was again subdivided, so that at the end of the last set of plates there was no rush of air between them, and a man looking through the aperture, with his face to the wind, was in a perfect calm. This was a useful arrangement, the look-out man’s eyes being as well protected as though behind a glass. A glass would not answer the purpose, as it would become obscured with spray.
The unfortunate circumstances which attended the completion of the ship prevented the introduction of these and many other arrangements which Mr. Brunel had originally proposed.[155]
In November 1855, the Directors proceeded to appoint a commander to the ship; and their choice fell upon Mr. William Harrison, one of the most distinguished of the captains of the Cunard Company’s steamers.
This appointment gave Mr. Brunel great satisfaction; he found in Captain Harrison a warm and faithful friend, and an able adviser on all matters connected with the completion and equipment of the ship.[156]
Before they came to a decision, the Directors asked Mr. Brunel to communicate to them his views on the considerations which ought to influence them in their choice.
The memorandum he drew up on the management of the great ship, and a letter on the duties of the chief engineer, are inserted at length, as forming a complete record of the principles which, in his opinion, should be followed ‘in the use of this new machine,’ while employed on the voyages which she was specially designed to make.
_Memorandum on the Management of the Great Ship._
October, 1855.
The question of the principles to be followed in the use of this new machine, for such it must be considered, and the character and the qualifications of the man to whom it is to be entrusted, and the points to which his attention must be particularly devoted, have long been subjects of deep and serious consideration with me.[157]
And the difficulties are complicated by the consideration that public opinion, and those established and universally received opinions which, being the result of experience, cannot be called prejudices, have to be considered, and must be yielded to to a great extent, even when somewhat opposed to sound reasoning, or to conclusions deliberately formed upon a due consideration of the novel circumstances under which we have to act; but, while conceding much to past experience, and to preconceived opinions, the real requirements of the case must have the first consideration.
Thus, as it is a ship that we have to navigate, public opinion, if nothing else, requires that we should have a sailor of undoubted experience and skill to command her; but although seamanship may be one of the essential conditions or qualifications for the commander, I think we shall find, upon examination, that the work we have to do, and the duties to be performed, and the qualifications we consequently require in the man who is to conduct this work, are so peculiar that mere seamanship, in the ordinary sense of the term, if it were to be solely relied upon, would be even a disadvantage rather than otherwise, and that we require much that is not necessarily found in the most perfect specimen of a seaman, and much that is far more difficult to find than the ordinary qualifications.
I wish particularly to impress this upon you: the subject has occupied long, frequent, and serious deliberations. I have come to the conclusion which you will no doubt readily acquiesce in, that our first practical mechanical success, upon which so much of our financial success hangs (although others might reap the benefit even of our failure in the first instance), will depend mainly upon the skilful management in our earliest voyages of the machine we are about to set afloat; but I have also come to the conclusion, the correctness of which may not be so immediately apparent to you, that this machine, though nominally a ship, not only admits of, but requires, a totally different management from that which may have successfully navigated ordinary ships, and that most of the habits, feelings, and sensations, amounting to instinct, possessed by a good sailor, and the peculiar power of skilful adaptation of expedients to emergencies, which constitute the merits of a first-rate sailor, have to be put aside for a time rather than applied in the first instance to make a successful commander of the vessel.
In navigating a small vessel, a man has to study the appearance of the weather, the direction of the wind, and that of the seas; to consider the probabilities of change; to vary his course more or less with reference to any of these causes, and according not only to the then state of all these operating causes, but also with reference to the probabilities of change; and with their consideration his mind is principally occupied, and it is in the exercise of judgment and foresight in these points that he shows his skill.
Steam navigation, and the gradual increase in the size of vessels, have no doubt materially modified this, but much still remains to occupy the mind of the commander of a steamer, with which not only we shall have nothing to do, but too much attention to which, from previous habits, would divert his attention from that which, under the different circumstances, will become much more important.
In the same manner, in manœuvring such a vessel in harbour, the ordinary modes would be totally inapplicable; whereas, by entirely discarding all previous practices, and keeping in his mind and making use of the peculiar powers which are at command in this vessel, and judiciously attending to the immense effect of the _vis inertiæ_, or momentum of such a mass, so far beyond that of anything now afloat that it becomes a totally _new_ influence, this machine may be managed by a skilful man with a facility which is not attainable with small craft; while such a mass would be destruction to itself or to anything that comes in contact with it, if treated at all in the same manner as even the largest steamers are now handled.
Another peculiarity to be attended to in the management of this mighty mass is that by no possibility must she be allowed to touch the ground.
Our ship will be found, I believe, if tried, to possess unusual strength: no combination of circumstances within the range of ordinary probabilities can cause such damage to her as to sink her, even if she were to be run on sharp rocks with deep water around; and I believe she might remain for months aground, exposed to the heaviest seas without serious damage. The lives of the passengers, and even the cargo generally, will be safe, almost perfectly safe, and so far she will be very different from and very superior to any vessel now afloat; but there will also be another great difference, although she may remain safely aground, she will probably remain so for a long time.
If she were to ground at high water or where there is a little tide, and when she happens to be rather light of coal, and should take in any water so as to deepen her, no ordinary appliances in the power of the crew will get her off, or, at all events, not without great loss of time, and at very heavy sacrifices. Such an event in the first year of her career would probably ruin our Company, as the grounding of the ‘Great Britain’ did the Great Western Steam-Ship Company, although it proved the good qualities of that ship, and thus advanced iron ship-building. A sailor will no doubt receive with disgust and as an insult the suggestion of the possibility of his running his ship ashore. We cannot afford, however, to rest contented with this expression of feeling, natural and praiseworthy as it may be: our circumstances are totally different; and that which is considered certainly as a serious evil, but still only an evil more or less serious, would be to us fatal; it is no longer a question of degree of injury--it is death. I have had some costly experience; I have had to do with many steamers--several remarkable for their size and their value, according to the ideas of the time, and two of them each in their day considered Leviathans, more wondered at than even ours, and exciting much more anxiety on the part of their promoters, and there was as much care taken in the selection of commanders as I ask you to take now; nevertheless both of these, to the ruin of the Company in one case, and almost every other steamer I have had anything to do with, has not merely touched, but been aground. Not a season hardly passes without a case of even a Queen’s ship going ashore, although navigated by men educated for the purpose, with the advantage of every appliance hitherto thought necessary and sufficient, and with fearful responsibility attached to them. All these are published cases known to the world; and if the log books of all the steamers were searched, I believe the result would be a list in which the ships that had not been aground would form the exceptions, and, in the majority of cases, the blunder is so gross, that the most far-fetched excuses of errors of compass and unknown currents, although in well-known channels, are obliged to be invented.
The real explanation is a simple one. Ships are navigated with far too reckless a confidence in the mere personal instinct and skill of those in command, and in their ability to get out of a scrape in time. Methodical systems and mechanical means of ensuring accuracy are far too much neglected, or rather have not kept pace at all with the great improvements in speed and the power of locomotion which science has introduced, whether in the construction of steam vessels or even of sailing ships, and which the advance of the day now calls for. There are no means at present used of taking soundings worth having while a ship is going fast through the water, or in time to be of any use if the soundings shoal rapidly; the trouble is so great and the operation so slow that it is not resorted to sufficiently often. The steering by compass is so rough and so coarse, that no real accuracy is attained. Good observations to determine position are taken at too long intervals of distance run, and consequently are subject to be interrupted for too long a period by what is called and supposed to be continual bad weather; although it would rarely happen, if persons were continually on the watch, who had nothing else to do or to think of, that twenty-four hours would pass without some glimpses of a star or of the sun. Thus with a speed of ten or fifteen knots, and cloudy weather, and, above all, with that unfortunate confidence of seamen to which I have referred, there is never any certainty just at the time when it is really required. No doubt, skilful seamen do generally arrive at an astonishing approximation in their estimates, and the results on the average are most successful, and remarkable proofs of the skill brought into action. But the instrumental means of attaining accuracy are lamentably in rear of the improvements that have been made in the means of locomotion, and have not at all kept pace with the vast increase of capital embarked in each individual case.
All these deficiencies are, however, easily remedied; the means do exist, or can be devised, and might be applied if we insisted on their application. We have seen numerous instances where the difficulties are admitted and grappled with systematically, and with what patience and skill a fleet has been piloted up unknown rivers full of shoals in China, and through intricate channels with covered rocks in the Baltic. In our case, the object to be attained is a vital one to us; and what I most dread is the confidence of our commander resulting from his previous experience preventing his appreciating the peculiarities of the case, and applying that greatly increased amount of method and system which is essential to change that, which is now rendered only highly probable by the skill of man, into mechanical certainty. The man who takes charge of such a machine, in which is embarked so large a capital, must have a mind capable of setting aside, without forgetting, all his previous experience and habits, and must be prepared to commence as an observer of new facts, and seize rapidly the results. A man of sense and observation, with a good mechanical head, and with decision and courage, would succeed without much previous nautical knowledge; but, unquestionably, a man familiar with all that is going on around would be much more competent, provided he does not allow his habits derived from former experience to induce him to neglect any of the new means of information in his power, to all which his former knowledge should be made subservient.
If much has to be unlearnt, or rather carefully set aside for the time, as generally inapplicable in its present shape, there is also much to be learnt in the navigation of such a vessel; and one of the most essential qualifications of the commander would be a belief in his want of experience, and a readiness to see the novelty of his position, and a cautious and sound but quick perception of the new and powerful influences and _new_ effects of those same causes with which he may have been familiar under very different circumstances.
The great mass and size of this vessel must necessarily render it so much less affected by the ordinary disturbing causes of wind and sea, that, practically, little attention ought to be paid to these, at least not as expecting the ordinary results; but other effects may be produced which must be carefully studied and learnt in the early voyages, so that they may be met and counteracted as they have been by experienced men under the present system. Thus, as an example of this class of effects to which I would refer, there is reason to believe that this vessel, although apparently unaffected by a wind on the beam, or a cross sea, which would be very noticeable even with the largest of the present steamers, would nevertheless have a steady and rather strong tendency to come up to the wind. A certain direction of a cross sea is not unlikely to produce a contrary effect. It is quite possible also that the apparent lee-way, or the deviation of the axis (or keel) of the ship from the line of the course, will be greater with the wind on the beam than with smaller vessels, although the actual drift or lee-way may be less; and all these effects will result from her great length (unless counteracted by causes I do not now foresee), and will probably be totally different in degree from any similar effects now felt. These effects must be carefully studied, and with a mind prepared to consider them as new, for they will be new and distinct from anything now experienced. In the same manner, and to a much greater degree, the effects of the speed which we must hope to attain will upset all the usual methods of determining accurately the position and the course of the vessel, and still more the precautions to be taken in approaching land. A 24 hours’ run, at 20 miles per hour, without a good observation, and with a possible error of estimate, or a doubt, at all events, of the exact effect of the set of currents, or of the speed of the ship through the water, or of the precise amount of lee-way, may easily make an error of 20 or 30 miles in position at the end of the day’s run.
On the other hand, by almost abandoning the present modes, and adopting measures which I shall point out presently, adapted to the new circumstances, a much greater degree of certainty and accuracy may be attained than is now even sought for. I have had the best advice on these points, both astronomical and nautical: the Astronomer Royal, Mr. Airy, who both as a man of science and a practical man, and by his official position, is the first authority on such matters, and Professor Smyth, of the Edinburgh Observatory, Captain Beecher of the Admiralty, and several other scientific naval men, have assisted me; and, under their advice, instruments are being constructed, and a system devised, which will admit of continuous observations being made with great accuracy at all times of the day, and particularly at night, and by means of which also a continuous correction of the ship’s compasses with the most minute accuracy can be kept up, and her position be ascertained with almost the same accuracy as a point on land; and I have their authority for saying that such improved means are desirable, and are attainable.
The importance and advantage of continuous observation throughout the twenty-four hours, whenever a glimpse can be obtained of any object which will answer the purpose, and even when the horizon is invisible, may not at first be evident, but it cannot be over-estimated. An exact knowledge of the ship’s movements will be soon acquired that would almost replace observation, and the average of numerous observations secures an accuracy which cannot be approached by any other method.
By a careful and continuous comparison of the exact distances run, with accurate records of the speed of the engine and of the ship through the water, registered by good instruments (the performance of which has been tested, and which are being made), and having proper reference to the varying draught of water of the vessel, the most precise measure of the speed of the vessel through the water can be learnt; and by careful observation of the force and direction of the wind, the effect of any given wind, and an accurate measure of her drift or lee-way, may be obtained; and then, by adhering strictly, without regard to wind or weather, to a course previously laid down on good charts, having upon them the sets of currents, as already observed, the true position of the ship may be determined at any moment, and there need never be the slightest hesitation, or any time or distance lost by doubts.
In addition to the instruments above named, I hope to be able to provide the means of sounding at moderate depths while the ship is going her full speed.
Having the means, then, of determining the ship’s course and position with much greater accuracy than is now practised, we must seek to make that course, or the distance to be run, the shortest possible, that is to say, the course which will occupy the least time.
The exact course to be taken by such a vessel must be determined upon and laid down upon the charts after a due consideration of all the circumstances which can possibly affect the time occupied in the voyage between any two points, and particularly by examining and considering well all the information which scientific observers have collected and recorded as to the currents, probabilities of fogs, or of ice, and other impediments, the chances of meeting vessels, which must be avoided as much as possible, the average direction of prevailing winds, varying such course, perhaps, in certain latitudes with the season of the year, but certainly not with the temporary direction or force of the winds or state of weather at the moment; for the speed which we shall attain renders these causes of secondary consideration, and would interfere with all ordinary calculations derived from present experience of the probable state of the wind in the new position which the ship would attain after a few hours’ run. The business of the commander would be, therefore, to adhere rigidly to the exact course previously deliberately determined upon, and not to be tempted to deviate except slightly, and even then only according to rules which he shall have previously laid down for himself.
The importance of adhering strictly to this rule cannot be over-estimated. The period occupied in a voyage will be materially influenced by the exact course followed, and as such course must be determined upon only by a calm and somewhat laborious study of documents, it cannot be safely determined upon except in the closet, that is, _before the voyage_, and uninfluenced by the excitement of hopes or by disappointments caused by difficulties.
The safety of the ship and of the enterprise may also mainly depend upon the rigid adherence to this rule.
With the means at his disposal for checking that course, and with the method and regularity involved by a rigid adherence to it, and a correction at once of any departure from it, a degree of certainty will be attained as to the ship’s position which will almost preclude the possibility of an accident, and which I consider practically invaluable as affecting the safety of our vessel. This rigid adherence to an exactly prescribed course will prevent any risk of that which is the cause of the greater number of losses. No inducement of fine weather, or a happy state of mind and body of the captain, or a desire to save time, or to show the beauties of a coast, or any other temporary cause, will lead to a nearer approach to dangerous points than had been previously determined upon as safe. The shortest and best route, the safest from all dangers, and giving the widest berth to all shores or shoals, having been laid down, must be kept to against all temptations.
Economy of fuel is another consideration of the highest importance. The engines are of power sufficient, if fully worked, to consume considerably more than the cargo provided. Large as may be the supply which the ship is capable of carrying, it is no more than that which is calculated as necessary for the voyage intended, with a moderate allowance for contingencies; and it must be borne in mind that the ordinary means of making up any deficiencies would be totally inapplicable in our case, since no supply capable of being drawn in an emergency from other sources would be sufficient.
The precise quantity calculated and provided must be made sufficient, or the consequences would be serious. The usual practice, therefore, of going ahead as fast as the engines will take the ship must be entirely abandoned. Careful observations, systematically pursued, will show the speed which, under different states of immersion, can be attained without a disproportionate expenditure of power, and to this speed the engines must be limited. A little experience will probably show that, under certain circumstances of immersion of the ship, or of the state of the sea, it may be economical to force the screw or the paddle engine, the one more than the other. This can only be determined by somewhat delicate and very precise and accurate observations. These must be made. It is not merely a question of degree, but our whole success depends upon the application, not of one, but of all these refinements.
A close study of the relative speed of the ship, as ascertained by the self-registering logs, and by continuous astronomical observations, compared with the expenditure of power in the engines as indicated by the number of revolutions constantly registered, and the power expended as measured and recorded by the chief engineer, will be necessary for some time to come, and until indeed the management of such large ships becomes as much a matter of rule as it is now, or perhaps ought to be more than it is, with smaller ones.
As to the use of the sails, while the engines are nevertheless in full action, it must be entirely a matter of experiment, and an experiment in which, again, all previous habits and prejudices must be set aside.
Whether a sail steadies such a ship usefully or not can be, and must therefore be, positively determined by measurement with proper instruments, and not by the sensations; and the result upon the speed of the vessel as compared with the power expended must, in like manner, be ascertained by positive observations and measurements. No past experience can do other than mislead. It is quite possible that the same means which improve the rate of the present large steamers may be prejudicial to our performance.
The commander must appreciate the necessity of all this study and attention to what is rather mechanical than nautical, or our voyage will be a failure. The difference between the peculiar qualities of such a floating mass as compared with those of the largest steamer now afloat, is likely to be as great as between the last and a 100-ton cutter; and the most prejudiced believer in the acquired skill of an old sailor who had learnt to manage the small vessel in the most perfect and masterly manner, would not expect him to be able to handle one of the present large steamers, still less to elicit the best performance out of her. In the same degree the man who takes the command of our ship must, if he is to succeed, enter upon his duties with a belief that he has nearly all to learn, at the same time that this feeling is perfectly consistent with a proper confidence in his own powers to master the new circumstances, and to succeed with this as he may have done with other vessels.
Finally, the commander’s attention must be devoted exclusively to the general management of the whole system under his control, and his attention must not be diverted by frivolous pursuits and unimportant occupations. I believe that even in the present large steamers much advantage would result from relieving the captain from all care of the passengers and cargo; but in our case, where we may have to provide for thousands instead of hundreds, and arranged in different classes, and living in completely separate saloons and compartments, the present system of a captain dining at the table and associating with the passengers would be impracticable, even if it were desirable. But for much more important reasons, and on general grounds, I think that while the commander is of course supreme over every department, he should not be embarrassed by undertaking any one, still less should he have his mind occupied with the troublesome and frivolous concerns of a vast hotel, nor should he be hampered by the necessity of attending to the hours and the forms of a large society. Moreover, I consider it essential that he should by his presence and control keep up the position and the sense of responsibility of the chief officers under him, by living and messing with them; the commander and those acting immediately under him must occupy a more dignified position than they now do.
The result of all these general views is, that the command of this ship must be considered to consist mainly in the superintending and keeping up in a high state of order the perfect working of a highly methodical pre-arranged system, by means of which the ship is to be made to go like a piece of very accurate machinery, precisely in the course which has been pre-arranged, and precisely at the speed, and with the consumption of power, which has been ascertained to be the highest attainable with the requisite economy; and there must be a proper establishment of assistants, competent to control each department of this system. As regards the constitution of this establishment, I consider the commander should have a staff of chief officers or captains. I believe three will be necessary, with a fourth performing general duties and ready to take the place of any one of the three; that one of them should always be in command of the ship (under the commander); that, besides these chief officers, there should be a master, corresponding to a master in a Queen’s ship, who would have assistants and calculators or clerks, whose duties would be to keep the ship’s reckoning, to keep up perfect and continuous observations, to calculate with precision and set from hour to hour the exact course by compass which has to be followed, to keep in the course determined upon by the captain, to keep a series of accurate observations and records of all matters that can affect the ship’s movements--duties involving an amount of science and practical astronomical and mathematical knowledge which requires a superior education, and which is found only in this class of men. The duty of the master would be therefore to supply the science necessary for the conduct of the ship, and to be the commander’s cyclopædia and book of reference, to be able at any moment to report to the commander the exact position of the ship and her course, and the variation of her compasses, and take the soundings, if any, to note the fact of a change in the temperature of the water, indicating approach of ice, and any other symptom or fact which can affect the ship’s movements--all which should be determined by continuous observations methodically and mechanically made, and not be dependent upon the chance of the commander’s anxiety or greater or less forethought. The chief engineer should also be a superior man, selected more for his general qualifications as a good director of men and machinery, than as a mere marine engineer. These should form a staff, and be of a standing to live and mess with the commander; so that each department should thus be furnished with a chief competent for the special duties of his department, and reporting to and acting under the general control of the commander.
That the principles thus laid down as to following exactly a prescribed and predetermined course, and as to regulating exactly the consumption of power and consequently of fuel, and the keeping up a system of what may be termed scientific observation for the purpose of ensuring this regularity, I submit should be rigidly enforced; and the commander should be required to adopt these principles as the guide of his conduct, and to use the measures that are placed at his disposal for working this machine in the manner and with the precision pointed out.
_Letter on the Duties of the Chief Engineer._
March 19, 1857.
The duties which I apprehend will devolve upon the chief engineer of our ship will be, firstly, the supreme direction and management of both the principal engines, and all the auxiliary engines and machinery worked by them in the ship; and as the construction of such a ship, and of many of its adjuncts, such as the iron masts and yards, steering apparatus, and other parts, are strictly of an engineering character, and such as in the event of repairs, particularly at sea or in foreign ports, would require a mechanical engineer rather than a shipwright, I think it must be made part of your duty, as the most competent officer, to make yourself thoroughly acquainted with the construction of the ship and all its parts, and all mechanism within it, so as to be prepared to take such share of responsibility as to the state of the structure of the ship as it may be found desirable to throw upon you as chief engineer, and at all events to be prepared to be the captain’s chief authority and responsible adviser on all matters of mechanical engineering.
The principal duty, however, will of course be the management of the engines, including the care of the paddle, screw, and other machinery immediately connected with the engines, or worked by them; and as the success of the ship as a steamboat will depend entirely upon the amount of power developed by the engines, in proportion to the fuel consumed, there is no limit to the degree of attention, of judgment, and of skill, that not only may be usefully applied, but that must be applied to ensure success.
I have no wish to alarm you as to the amount of work or responsibility that will devolve upon you; my object is rather to show you the opportunity afforded of displaying judgment, skill, and assiduous attention, and thus, as I hope, to excite your ambition, when I seek to draw your attention very strongly to the peculiarities of this case.
In ordinary steam navigation, whatever perfection has as yet been sought for or attained, the business of the engineer has been mainly to keep the engines in perfect order, and to develope the greatest amount of power possible, and, secondly, to effect as great economy as possible in the consumption of fuel; but the latter has been merely a question of economy in a pecuniary point of view, and not of necessity, and has been entirely secondary to the first condition, so much so that the most successful ships have not been by any means the most economical, on the contrary, they have been rather extravagant consumers.
In the present case, the circumstances are totally different, and it will be essential that you should change altogether your accustomed views on this subject.
This ship is built to go round the world with a defined and limited amount of fuel, which you have no power to exceed, or rather, if you exceed it, at any part of the voyage, the whole is a failure. The circumstances are therefore reversed, with this additional condition, that there is no medium or partial success. In the ordinary cases you have a limited power of engine and an excess of fuel, in which it is desirable but not essential that you should effect economy; in the present case you have a limited and defined quantity of fuel to consume, with an excess of engine power, and the art will be to obtain the largest total amount of power from this fuel, expending it progressively, and in such a manner as to reach a given point. To effect this, and obtain the best possible results, will require of course that the engines should be kept in the best possible order; but this, although a preliminary condition, is an ordinary one, requiring no peculiar duties or exercise of judgment, and must be assumed, as on all occasions, a matter of course. The peculiar duties in our case will be the continuous study in every trifling detail that can effect the result of the means of obtaining the largest amount of steam from the defined expenditure of fuel and the use of this steam, so as to obtain the largest amount of power, and the largest amount of result.
The mere study of this question must necessarily occupy some time, and for several voyages it will be a subject of experiment; but the more rapidly positive information can be obtained, the more prompt and certain will be our success. To attain success will require a degree of attention to every minute detail, which it has never yet been necessary or profitable to devote to this branch.
The continuous weighing out of coals and measure of the products of each boiler (for which means will be provided), the continual observation of the extent to which blowing-off is desirable, the continuous measure by indicator of the performance of the engines under different pressures and degrees of expansion, so that you can at all times furnish the captain with the exact performances of the two engines, and the cost of fuel required to produce given results in each; so that he may have the means of comparing your expenditure with the results he obtained in the speed of the ship, and of learning the relative beneficial effects of employing more or less the paddle or the screw in different states of weather, or different immersions of the ship, will be required; and every method of increasing the performance of each gang of stokers, and of stimulating their skill and care, and every refinement in each separate branch of the work, to effect economy of fuel, or rather, development of power with a given amount of fuel, will be necessary. We all know full well how, if every effort is continuously made and every possible care is continuously bestowed in each department, 4 or 5 per cent. can be saved or gained in many points, and at many times in the 24 hours, between the drawing of the coals from the bunkers and the development of power at the paddle board or the screw blades; and if only 1 per cent. can be thus gained in a few points, the aggregate will soon amount to 10 per cent., which with us may make the difference between success and failure. All these things will require judgment, thought and attention, rather than labour, and, above all, close watching and method, and good management of men.
Besides these more than ordinary duties during the voyage, the only peculiarity in the service will be that, with such a costly machine, the mere interest of money and fixed expenditure upon which will not be short of 200_l_. a day, and the perfect state of which is so essential, you will be required to give more attention to the machinery when in port than is usually required.
I trust that this strong but not exaggerated statement of what would be expected of the chief engineer, will excite your desire to undertake the duties, rather than deter you from seeking the post; and that, if the Directors should accept the offer of your services, you will enter upon the duties with confidence, though with a sense of their serious importance. In the event of your appointment, it will be a necessary condition that you should be able to commence at once the supervision of the erection of the engines. This work is already much farther advanced than I should have wished it to be before the chief engineer had taken charge of it. I attach great importance to his having that familiar knowledge of all the parts and their condition, which no study of drawings can give so well as actual inspection during erection, and I wish also that he should satisfy himself of the perfect truth of every adjustment.
It will be seen from the documents which have been printed in this chapter how ‘deeply and seriously’ Mr. Brunel had considered all the conditions which were, in his opinion, necessary for the economical construction, and the successful employment, of the great ship; but it is hardly possible, by means of extracts from his correspondence, to convey an adequate impression of the amount of labour he expended--from the year 1852 to the last days of his life--on the supervision of every detail of the work. ‘The fact is,’ he said, ‘I never embarked in any one thing to which I have so entirely devoted myself, and to which I have devoted so much time, thought, and labour, and on the success of which I have staked so much reputation.’
Heavy as Mr. Brunel’s duties were in October 1854, when he wrote these words, a far greater amount of labour was subsequently imposed upon him.
During the year 1855 financial difficulties arose which interfered with the progress of the ship; and at last, in February 1856, although Mr. Brunel had done everything in his power to prevent the necessity of such a step, the works were suspended; and they were not resumed till the end of May, after which date they were carried on by the Company under the supervision of the existing staff. It was greatly against Mr. Brunel’s wishes that this was attempted, except as a temporary measure, as he considered it impossible for a company to carry on such a work efficiently and economically.
Notwithstanding all these difficulties, that which seemed at first only a confused mass of iron assumed by slow degrees the graceful proportions of a ‘great ship’; and the hull of the vessel was completed by the end of the summer of 1857, so far as it was desirable to proceed before the commencement of the launching operations.