At length, though not with all the energy that he desired, Lord Dundonald's engine was put to the test by the Admiralty during the Earl of Haddington's tenure of office in that department. In May, 1842, he was invited by the new First Lord, who, in common with all the world, was aware of the zeal and intelligence with which he had devoted himself to the consideration of every branch of naval science, to communicate his opinions thereupon. The first result of this invitation was a letter showing remarkable discernment of evils then existing, and curiously anticipating some later efforts to correct them.
"The slow progress," wrote Lord Dundonald, on the 7th of June, "which the naval service has made towards its present ameliorated state—yet far from perfection—has not permitted any one Board of Admiralty in my time to stand pre-eminently distinguished for decisive improvements. These have rather been effected by the gradual changes which time occasions, or by following the example of America, or even of France, than by encouraging efforts of native genius. This has arisen from causes easily remedied; one of which is, that the rejection or adoption of proffered improvements has depended on the decision of several authorities, who consequently feel little individual responsibility, and imagine themselves liable to censure only for a change of system. Thus, my lord, a still heavier responsibility has, in fact, been incurred by continuing, long after the most superficial observation demanded a change, to construct small ships of the line, and little frigates, which the great practical skill and bravery of our countrymen were taxed to defend against the powerful eighty-gun ships of France and the large frigates of America. This timidity as to change caused many years to elapse, after the commercial use of steam-vessels, before the naval department possessed even a tug-boat. Hence the mischievous economy manifested by the purchase of worthless merchant steamers; hence the subsequent parsimonious project of building small steam-vessels fitted with engines immersed beyond their bearing, and deficient in every requisite for purposes of war. I am not one of those, my lord, who deem it advantageous to act on the belief that one Englishman can beat two Frenchmen. I am inclined to doubt whether a practical demonstration of that saying might not be attended with disastrous consequences. Long habitude reared experienced British officers, who are now replaced by others who possess less nautical skill, and are nearer on a par with those of France, in regard to whose education every pains has been taken by its Government. I do not presume to advise that your lordship should adopt changes precipitately, nor without consulting those who may be most competent to judge; no, nor even then that the best measures should be prematurely disclosed, so as to give intimation to other nations of the vast increase of power which may suddenly be rendered available. But I venture to suggest that you may quietly prepare the means of effecting purposes which neither the ordinary ships of war nor the present steam-ships in the navy can accomplish. Permanent blockades, my lord, are now quite out of the question; and so, in my opinion, are all our ordinary naval tactics. A couple of heavy line-of-battle ships, suddenly fitted, on the outbreak of war, with adequate steam-power, would decide the successful result of a general action; and I am assured that I could show your lordship how to fit a steam-ship which, in scouring the Channel or ranging the coast, could take or destroy every steam-ship belonging to France that came within view."
That offer was accepted by the Earl of Haddington, who, being at Portsmouth in August, made personal inspection of some experiments in which Lord Dundonald was there engaging; and the result of that inspection was that he promptly arranged for the introduction, at the public expense, of the rotary engine in the Firefly, a small steam-vessel which, like many others, the Government had bought and found useless, by reason of its clumsy machinery. In her, with no more than the usual delay occasioned by the co-operation of official routine with private enterprise, in which Lord Dundonald had the assistance of Mr. Renton and Messrs. Bramah, the experiment was tried and found to answer so well, in spite of the difficulties incident to a first attempt, that it was resolved to develop it further in a frigate to be built throughout in accordance with his plans for the improved construction of shipping.
To these he had lately made some valuable additions. On the 19th of January, 1843, a patent was granted to him for various improvements in engines and other machinery, one of which was an apparatus for propelling vessels. "This improved propeller," says a competent authority, "consists of an arrangement of propelling blades immerged beneath the water, in the manner now usual in screw vessels; but, instead of the blades being set at right angles with the propeller-shaft, they form an angle therewith. One important effect of this arrangement is that it corrects the centrifugal action of the screw; for whereas, in common screws, the water which is discharged backwards assumes a conical figure, enlarging as it recedes, in a screw formed on Lord Dundonald's plan the outline of the moving water will be cylindrical, the centrifugal action being counteracted by the convergent action due to the backward inclination of the propelling blades. It is found, practically, that screws constructed upon this principle give a better result than ordinary screws."[17]
Another invention patented by Lord Dundonald at the same time was a modification of the boilers used for steam-engines. "These boilers," says the same critic, "are constructed with a double tier of furnaces and with upright tubes, the water being contained within the tubes and the smoke impinging upon them on its passage to the chimney. This species of boiler is found to be very efficient. A hanging bridge is introduced to retain the heat in the upper part of the flue in which the tubes are erected. By inserting a short piece of tube in the upper extremity of each tube within the boiler the upward circulation of the water within the tubes was increased as the length of the lighter column of water was augmented, while the length of the gravitating column remained without alteration."[18]
"I believe," he said in a letter to Lord Haddington dated the 22nd of May, 1843, "that all our old vessels of war, save the class of eighty-gun ships and a few first-rate and large frigates, are almost worthless; whilst our steam department is deficient in most of the properties which constitute effective vessels. No blockades worthy of the name can now be maintained by fleets of sailing ships; nor can accompanying steamships be kept for months and years even in 'approximate readiness,' awaiting the distant night when it may suit the enemy to attack our blockading force or quietly to slip out in the dark in order to assail our commerce in other quarters. I have, my lord, during the last twelve years actually disbursed, to the great inconvenience of my family, upwards of 16,000l. to promote nautical objects which appeared to me of importance. Your lordship knows their nature, and it is in no way difficult to ascertain their reality. I consider that several, if not all our line-of-battle ships, should have the benefit of mechanical power, say to the extent of a hundred horses—the machinery to be placed out of the reach of shot. The construction of new ships on the best lines that could be found would prove more judicious than repairing old ones, however apparently cheap such repairs may be; for a few powerful and quick-sailing ships are preferable to a multitude which can neither successfully chase, nor escape from, an enemy."
That allusion to the "best lines" of ship-building, and some of Lord Dundonald's other views on naval architecture, will be explained by another letter written by him to Lord Haddington, three months before, on the 20th of February. "I have lately," he said, "submitted to the consideration of Sir George Cockburn an axiom for the uniform delineation of consecutive parabolic curves, forming a series of lines presenting the least resistance in the submerged portion of ships and vessels—an axiom never before so applied in naval architecture, as is manifest from the discrepant forms of our ships of war. I also offered to Sir George's attention a new propeller and method of adapting propellers to sailing ships in her Majesty's service, free from the disadvantages of paddle-wheels and from the injurious consequences of lessening the buoyancy and weakening the strength of the after part of ships by a prolongation of the 'dead wood,' and by cutting a large hole through it for the insertion of the Archimedean screw. The favourable impression made on the mind of Sir George, and my own deliberate conviction of the importance of these improvements, and of others then briefly touched on, lead me, by reason of the lamented indisposition of that talented officer, now personally, instead of through him, to offer them to your lordship's attention.
"The French, as your lordship is well aware, are making great exertions to advance their steam department, especially in the Mediterranean, where calms are frequent and their coal is abundant—doubtless in the hope of thereby preventing the future blockade of Toulon, and of keeping open their intercourse with Algiers; which would be equivalent to possessing the dominion of the Mediterranean Sea, where a British blockading fleet of sailing ships must, under such circumstances, themselves be protected. In saying this, my lord, I beg to be understood as by no means depreciating the capabilities of our common ships of war, whilst they possess the power of motion, but as holding them to be quite unfit for blockades, and exposed to great peril where calms are of frequent occurrence and long duration. Indeed, it may be worthy of your lordship's serious consideration whether, in another point of view, it might not be judicious to place steam-engines in some, at least, of our line-of-battle ships, in order to divert the attention of foreign nations from the exclusive employment of mechanical propelling power to purposes of naval war, whereby British officers and seamen, deprived of the means of displaying their superior skill, become reduced to a par with the trained bands of Continental states.
"I have prepared a model in bronze of a steam-frigate possessing peculiar properties, founded on the before-mentioned axiom, which, I do not hesitate to submit to your lordship, would save vast sums wasted in the construction of inferior ships and vessels, by enabling the Admiralty, on unerring data, to stereotype—if I may use the expression—every curve in every rate or class of ships, and so impose on constructors the undeviating task of adhering to the lines and models scientifically determined on by their lordships."[19]
Great interest attended the development of Lord Dundonald's inventions. "I need hardly assure you," wrote Lord Minto, on the 4th of October, "of the very great satisfaction I derive from the continued and increasing success of your rotatory engine; and I shall now look with no little impatience for further evidence of its merits in the new steam-frigate to which it is to be applied. I am glad, also, that you have turned your attention to the construction of steamers of war. I have never been satisfied with the properties of these vessels, much as their construction has undoubtedly been improved of late years. It is certainly a difficult subject, because some of the qualities essential to a vessel under sail can only be obtained by some deviation from the form calculated to give the greatest speed under steam; and I consider fair sailing powers, so as under all circumstances to keep company with a fleet, as not less important than speed and power as a steamer. The best combination of these very different qualities, or that which will upon the whole produce the most serviceable ship, is yet to be sought. I think, also, that sufficient consideration has not yet been given to the correction of that very grievous defect, the great uneasiness and excessive rolling of all these vessels, from the low position of the weights they carry. There is another object in connection with your engine which I had constantly in view: I mean its adaptation in the high-pressure form to our ships of war in general. It was my intention, had I remained in office, to have fitted a frigate with one of your high-pressure engines—not very high, however—with a view, if the experiment answered, to the introduction of an occasional steam power in all ships of the line. I believe you and I may probably differ as to the amount of steam power it might be advisable to give such ships, and that you would wish to steam the Vanguard or the Queen at the rate of ten miles an hour. My wishes are much more humble, and I should be perfectly satisfied with an amount of power sufficient to give steerage way under all circumstances, to carry the ship into or out of action, and to afford her some assistance in clearing off a lee-shore—something about equivalent to five knots—an amount of power that might probably be obtained, together with some fuel for occasional use, without encroaching too much upon the stowage of the ship. I shall be extremely glad if you can induce Lord Haddington to direct his attention to this object."