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.