SHIPS.
A SHIP, according to the common form of building, is one of the frailest of vessels that ever art, in its infancy, constructed. The hull consists of a series of pieces of timber fastened at right angles to each other; which in their aggregate are so ponde- rbus, and, from the mode in which they are fastened, cohere so slightly, that it requires the actual external pressure of the water to hold them together. Under ordinary circumstances, whenever a ship takes the ground, and the support from without is with- drawn, it falls to pieces on the slightest agitation, from the mere effect of its own gravity. Not only is the form of building of all others the weakest, and only to be perfectly sustained by the pres- sure of the denser fluid from without, but the expedients adopted with a view to keep that fluid in its proper place are of the Most bungling and imperfect kind.
It might be supposed, that, however ignorant of the principle of diagonal ties, common sense would; without any instruction,' have taught a shipbuilder to use all accessible means to prevent his vessel from leaking. To leave a hole unstopped, where the stopping of it is matter of plain and practicable necessity, seems the very sum of stupidity. Yet this sum of stupidity has been attained to, and is still persevered in, by nearly all the ship- builders in the world. Nay, the resources of art have been called into action still further to weaken what was previously feeble; and means and appliances have been used to make that doubly hazardous which was naturally obnoxious to injury. The plank' which runs parallel and next to the keel—the bottom plank, ag one of the uninitiated would call it—is termed by the shipbuilders the " garboard streak." If there be any part of the vessel that requires to be stronger than another, with a vie* to guard against leaking, it is this plank ; for it is plain to the meanest capacity,' that the pressure of the water must increase in force as we de-- scend—that a very small hole at the extreme depth of the vessel's' hold, will pour in a much greater stream than a hole of larger di mensions near the water-line ; added to this, a damage, in the former case, is got at, with much greater difficulty than in the latter. Now, would it be believed, that not only is this "gar- board streak" not stronger than the rest of the planking, but that it is invariably weaker—that the substance of it is cut into and channeled in order to serve as a water-duet for the pumps—that in a vessel of a thousand tons, the utmost defence that is placed between the crew, the pissengers, the cargo, and destruction, even in its first voyage, and in its best and soundest state, is two inches of oak timber? that a touch from a pointed bit of coral—a scratch of its own anchor—is sufficient, at any time, to drown, with all its contents, the proudest Indiaman that ever floated? But this is not all. The " garboard streak" is not the only vul- nerable point; every part, from the keel to the water-line, is equally unsafe. Pierce the outer planking, and down goes the ship : i. e. let one tenth part of the substance of its mighty and appa- rently substantial sides be destroyed, and the whole is destroyed. How is this? landsmen will say. Nothing is easier of explanation. The outer planking is the only part of the vessel that is impervious to water. Destroy that, and the Royal George is as much at the mercy of the waves, as was the coracle of CARACTACUS, when the cow-hide that covered its wicker-work was destroyed. The pon- derous ribs gape to admit the full stream; the inner planking, though somewhat more closely fitted, is equally pervious. Sir ROBERT SEPPINGS, in the Naval marine, had the merit of first applying a remedy to the gross and apparent defects of ship- building after the old plan. He remedied its weakness by the in- troduction of diagonal ties; he filled up the interstices between the ribs, so as to render the entire wall of the vessel's sides equally waterproof. Vessels built according to Sir ROBERT'S plan are immeasurably stronger; they can sustain much longer the fury of the waves afloat, and they can take the ground with much more security. Before they can spring a leak, it is abso- lutely necessary that the entire side be beaten in or perforated, or that the cohesion of the different parts of the framework be wholly broken. When a vessel, built according to the old plan, is driven ashore in blowing weather, the almost inevitable conse- quence is its total destruction in an hour or two. Hundreds of lives, and tens of thousands of property, are lost every year, that would have been saved had the wrecked ship been strong enough to hold together for a single tide. Sir ROBERT SEPPINGS'S plan presents an infallible remedy for such cases. If a vessel of his build can- not be got off a rock or shoal, it will at least keep together while on it, until the crew be got off. As we have already noticed, the smallest external damage suffices to sink a vessel built after the old plan. When such a vessel takes the ground, it is therefore, not uncommonly, as dangerous to heave it off, as to let it remain. We might cite the Invincible, seventy-four, at Yarmouth—the Abergavenny, Indianian, at Portland ; but examples are trite of vessels that have touched the sand even, sinking the instant they were heaved into deep water. Against every such accident, Sir ROBERT SEPPINGS'S plan is an effectual safeguard. We had long thought, that his invention (for it may well be called so) was incapable of improvement; but Mr. BALLINGALL, a gentleman who acts as manager of the Kirkaldy- arid London Shipping Company, has offered a suggestion, which does seem no inconsiderable improvement. In the old plan, only the outer planking is rendered waterproof; in the new, the timbers are made waterproof. Mr. BALLINGALL makes assurance doubly sure, by calking the inner planking. Not only is this an addi- tional safeguard against leaks—it is the best preventive of rot, by keeping the timbers from contact with the air, the grand decayer of dead, as it is the grand sustainer of living vegetable as well as animal substances. Sir ROBERT SEPPINGS 'S plan has been hitherto introduced into the Navy only; Mr. BALLINGALL'S wishes are directed towards the perfecting of the Commercial marine. To persons engaged in building vessels for the purposes of trade, his book may, indeed, be looked on as a complete manual.* Mr. BALLINGALL does not stop short by providing for the safety of the vessel. He has also invented an ingenious and simple method of building, by which, in case of a vessel's bottom being knocked in, it might yet float its crew—the under deck acting as a false bot- tom. He gives plans, moreover, for readily conveying the water in the hold, whether from leakage or otherwise, to the well; for protecting the pumps from being choked by the sand-ballast; and he shows, plainly and practically, how water may be drawn from the vessel's bilge • where its accumulation, while on a wind, is very often extremely injurious to a perishable cargo. To each and to all of these plans of Mr. BALLINGALL, which serve to perfect what Sir ROBERT SEPPINGS so happily began, there is, in the eyes of practical men, but one objection—they will somewhat enhance the expense of shipbuilding. The exact amount of the enhancement we cannot pretend to determine with accuracy ; but we feel fully persuaded, when there is set against it the wonderful increase of security to crew and cargo, and, as a consequence, the extended duration of the vessel, and the dimi- nution of sea-risk and insurance, the additional cost will return a large interest in savings. We wish, most heartily, all success to Mr. BALLINGALL'S endeavours. They who "go down to the sea in ships," whose business is in the" mighty waters," pursue a trade as rough and perilous to individuals as it is important to the community: and he is most benevolently and patriotically employed, who shall devise any scheme by which ever so small a portion of the labour and peril may be certainly abated.
• The title of Mr. Etia.mintau.'s book is The Mercantile Navy Improved.
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