MODERN IMPROVEMENTS, ADOPTED or SUG GESTED. Discontinuing the ceiling or inside lining of ships, substituting diagonal trusses, and filling up the intermediate spaces between the timbers with old wood, not applicable to any other purpose, have been lately adopted in the building of many of his majesty's ships, particularly the Tremendous, built by Mr. Seppings, which was launched without breaking or hogging the tenth part of an inch; she sails better than most ships of her class, is perfectly dry, betrays no signs of weakness, and is in every respect what may be called a crack-ship. Instead of exposing a ship six years on the stocks, with all the inconveniences and ill consequences arising from so long a period; twelve months would be quite sufficient to complete a ship, when the necessary quantity of dry and duly-seasoned timber was collected and prepared on the spot. This, however, is not the practice with those built for the royal navy; trees which have been felled six years, and trees which have scarcely left the forest as many months, greet one another in the same ship. These timbers are closed up with plank of many inches thick, which must necessarily be soaked with wet, in order to bend it to the frame of the ship; and, as it becomes dry, shrinks from its work. Mr. Perings, therefore, suggests the propriety of building ships under cover. This is not a new idea, as the Swedes build all their ships of war at Carlscrona in covered docks. The slips in the naval arsenal at Venice are roofed; the French have a covered dock at Brest; and it was reported even by the commissioners of the navy to the commissioners of the land revenue, in 1789, that if ships were built under cover, and roofs continued over them while they remain on the slips, it would be a means of rendering them still more lasting.' Short as the duration of our present ships of war is, it becomes considerably abridged in those cases in which North American oak is mixed in any quantity with our own; because it is extremely susceptible of the dry rot, which is forth with communicated to any wood that comes in contact with it. Nothing therefore but necessity, and the apprehension of a deficiency of English oak, should induce government to use that of American growth. England, though the first naval power in the universe, and equal to all the rest united, yet she is deficient in proper accommodations for her navy. Her dock-yards have risen from small beginnings to their present state, by a succession of expedients and make-shifts. The navy which they have created has altogether outgrown them; they are wanting in extent and in the conveniencies due to so magnificent a fleet. The expense of a covered dock would be doubly saved in the first line-of-battle ship built in it; and the workmen would perform their work sooner and better, because no kind of weather would interrupt their progress; the ship would be caulked, painted, and coppered when dry, to the exclusion of partial leaks, suffocating damps, and oozing drip. Many useful hints relative to the construction and preservation of ships have been given by Richard Pering, esq., of Plymouth dock-yard, in his pamphlet on the Causes of premature Decay in our Wooden-Bulwarks, &c., published in 1812. Since the above was written, Mr. Pering's suggestion, of building ships under cover, has been generally adopted in his majesty's dock-yards. The building of the Talavera, on Sir R. Seppings' plan, and her great comparative strength, led to the practice of putting together the frames of ships of the line from timbers of reduced lengths, and dispensing altogether with the chocks used for uniting their extremities, or, as they are technically called, their heads and heels. Sir Robert brought the butt ends of the timbers together and kept them together by means of a round dowal or coak like the fellies of a carriage wheel. ap Another great improvement introduced by him is the round stern, which, though at first pears an unsightly substitute for the old grotesque carved work, is even in appearance more consistent with the sweeping lines of a ship's bottom, than the cutting them off abruptly in a square stern. But the additional strength thus given to a ship, in that part which was hitherto the weakest, is sufficient to recommend the adoption of the plan, in all large ships. Sir Robert has thus enumerated the advantages gained by circular sterns: 1. They give additional strength to the whole fabric of a ship. 2. They afford additional force in point of defence. 3. They admit of the guns being run out in a similar way to those in the sides. 4. From the circular form, and mode of carrying up the timbers, an additional protection against shot is obtained, if the ship should be raked. 5. The stern being equally strong as the bow, no serious injury can accrue in the event of the ship being pooped; and the ship may be moorde, if so required, by the stern. 6. A ship will sail better upon a wind, from the removal of the projections of the quartergalleries. 7. Ships of the line have now a stern-walk protected by a veranda, and so contrived that the officers can walk all round, can observe the set of the sails, and the fleet in all directions. 8. The compass timber heretofore expended for transoms is substituted with straight timber, and worked nearly to a right angle, which affords a considerable saving in the consumption of timber. 9. The counter being done away, by the circular stern, the danger which arose from boats being caught under it is obviated. We have here the pleasure of introducing an original paper from the pen of a friend long engaged in the art of which we are treating Joseph Brindley, esq., late of Rochester. He suggests what he considers himself entitled to, call a new system of naval architecture. I can easily conceive,' says Mr. Brindley, that if a person tolerably acquainted with the first principles of mechanics (although he had never before seen a ship) were to examine minutely the various parts as now built in the ordinary way, he would be struck with surprise at the huge masses of timber so disproportionably arranged, and so inadequately connected to gether. It is therefore intended, by the introduction of a new principle, to render the construction of ships and vessels for navigation stronger and more perfect than any heretofore, and consequently beyond all comparison more secure, both as it respects the property as well as the lives of all who embark in them. 'In describing some of the many advantages that must result from this new principle in shipbuilding, I shall at present,' continues this gentleman, only confine myself to a very few particulars, which, from their importance, cannot, I think, fail to engage the immediate attention of the public, as well as of the members of his majesty's government: for I am prepared to assert that, by by a proper combination of plank timber, agreeably to the methods I recommend, and which, with a very trifling exception, need not exceed one inch to six inches in thickness, eighteen feet to twenty-four feet in length, and nine inches to twelve inches in breadth, ships and vessels of every class may be built stronger, sail faster, and stow larger cargoes than any now in existence, built upon the present ordinary mode of construction. And, when it is considered that this combination will consist entirely of young straight timber, I need not insult common sense by attempting to prove their advantages, especially when the lives as well as the property of millions are indentified with them. Every one in the least acquainted with the subject knows that a ship is a ponderous body, constantly in motion; that it consists of timbers and planks, connected together by fastenings of wood, iron, or copper, and that it is entirely upon a proper arrangement of these various materials, and combining them in their due proportions, that the strength of the whole fabric depends; for, if the materials are larger in proportion to the fastenings, they create a partial weakness, or if they are not properly arranged, so that each combination of every part bears its own proportionate resistance, the bad effects are the same; that is, if timbers and planks are disproportionably made stronger at one part than another, then this partial security is still an injury, especially in all moving bodies, inasmuch as by the momentum of the vessel the unnecessary weight causes so much more strain on the weaker parts; hence the difficulty in building a large ship so strong as a small one, although the several scantlings appear to be upon a proportionate scale. 'Now I contend that, by the present ordinary mode of ship-building, the materials are not so arranged as for each part to possess a proportionate strength, nor are the fastenings sufficiently strong for combining them together. And here I beg to call the attention of all parties interested, as well as the public in general, to the fatal delusion which has continued so long: viz. that ships should be so constructed as to have the principal strength placed up and down the sides, in the direction athwart-ships, and in the mouldings of the frame timbers: the ship is thus cut asunder at every joint, instead of which the strength ought more particularly to be placed in the fore and aft planking; for it is a well known fact that all ships first prove their weakness longitudinally, from the straining in the direction from the head to the stern. This is very obvious to all who will take the trouble to examine; for it should be particularly noticed that between all frame timbers there are spaces technically called openings, and at all these places the ship is completely cut asunder athwart-ships, as will be seen in plate IV., SHIP-BUILDING. See the openings a, b, c, d, and the timbers E, F, G, H; were it not for the fore and aft planking, the whole mass of timbers that compose the frame would fall to pieces; for without the planks they have no connexion whatsoever. I therefore recommend the discontinuance of frame timbers, except such floor timbers as may be necessary for water courses, and instead thereof to work a greater number of planks fore and aft ways, agreeably to the principle contained in those improvements for which his majesty has been pleased to grant me his royal letters patent. By the way of comparison, and for the sake of being more explicit, I have shown by two figures, 4 and 5, the present methods, and by figures 1, 2, and 3, my improved methods, of uniting the component parts of a ship together. 6 Figure 4 describes the shape of the midship section, as usually built, supposed to be cut asunder in the athwart-ship direction, and also the ends of the inside and outside planking fastened to the frame timbers. It is evident that at a, a, a, a, which show the ends of the timbers like so many joints cut off and butting against each other, the strength of the arch from keel to gunnel is completely destroyed, and it is only by the timbers being scarfed over and bolted sideways that they hold together; and even then so weak is the construction, that, in raising them to go into their proper stations in the body of the ship's frame, this imperfect combination of timbers, by being cut off at those places marked a, a, a, a, will not bear its own weight, but almost invariably alter its shape, and moves out of the first position in which they were bolted together. I here beg leave to observe that this mode, so very defective, is the best now practised in his majesty's dock-yards, as well as in those merchants' yards where the best ships are built; for 230 SHIP-BUILDING. in most parts of this kingdom it is common to 'It will be seen upon a larger scale, figure 1, alternate layers of plank fore and aft being "There are other advantages attending the above plans which might be stated: such as great sav Without much diffiing in the expense, especially in the use of all young small straight timber, and the facility by which it can be obtained. |