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of Mr. Pepys, secretary of the Admiralty, that, after 47 years, 'all the ancient timber then remaining in her, was still so hard that it was no easy matter to drive a nail into it. He farther observes, that trees felled in the spring are full of sap, which remains in the pores and putrities ; leaving the wood full of cavities, which make the timber weak, subjects it to rifts or gapes, and causes it to shrink; that, in Staffordshire, therefore, they bark the trees in the spring, and leave them standing till winter, and fell them when the sap has subsided; and he quotes the concurring testimony of Vitruvius and Pliny, that if the sap be let out of the oak while yet living, it will acquire almost a perpetuity of duration.
There can be no question that winter-felled timber is far superior to that which is cut down in the spring. The Montague, noticed before, was wholly built of winter-felled timber; but the advantages of stripping off the bark, while standing, are not so clearly established. It is thought in France, that timber acquires considerable durability by it
. In England, the only experiment, we believe, is that of the Hawke sloop of war, which was built at Deptford in 1793, one half with timber stripped of its bark while standing, the other half with timber felled in the ordinary way. Ten years alterwards she was broken up, when no visible difference was apparent in the state of decay of the two kinds of timber.
From what we have premised, the rapid decay of many of the ships built since the recommencement of hostilities in 1803, admits of an easy explanation. It has generally been supposed that when Lord Spencer quitted the Adnuiralty in 1801, he left an efficient fleet; this was by no means the case. It was numerous, indeed; but many of the ships were nearly worn out. The avowed system of the new ministry being that of economy, Lord St. Vincent determined, in order to give the better effect to it in the naval department, to build no more ships of war in the merchants’ yards. The King's yards were almost wholly occupied in patching up those actually in commission, and those brought forward from the ordinary. The consequence was, that when Lord Melville in 1804 succeeded to the Admiralty, he found the navy wholly inadequate to the situation of the country, threatened as it then was with immediate invasion; scarcely one of the ships in commission had more than three years to run, most of them but two, and many only one: a few, and but a few, new ones were slowly coming forwards in the King's yards, and none in the merchants' yards. It therefore became absolutely necessary to have recourse to private builders, who were wholly unprepared with materials. Contracts, however, were entered into at advanced prices, the axe was set to work, and trees which were one year growing in the forest, were, in the next, floating on the ocean: and the demand since that time has trodden
so closely on the heels of supply, that few, if any, ships have been built, either in the royal or private yards, with timber duly seasoned.
Another cause of this premature decay has been ascribed to the introduction of foreign timber into our dock-yards, and to the practice which has very injudiciqusly prevailed of late, of intermixing it with native oak. The Queen Charlotte was nearly seven years in building : some of the timber of native growth was seasoned, some of it was quite green; some of it consisted of Canada oak, and some of pitch pine, both peculiarly susceptible of the dry-rot. This assemblage of heterogeneous materials was certainly not prudent. Different woods possess different kinds of oils or acids, and experiments have not yet determined what effects are produced by their being brought into contact. There are, no doubt, between woods, as well as between other bodies, certain sympathies and antipathies, the operations of which have sensible effects on their contiguous surfaces. Almost the whole of the Queen Charlotte was rotten from the water line upwards, and in many parts below it, and her timbers were covered with as many different species of the boletus as there were different kinds of wood used in her construction. All this is perfectly accordant with our theory of the dry-rot; but, if our information be correct, we have much stronger 'proofs of its being the true one—for as soon as this unfortunate ship was closed in, stoves, strongly heated, were placed in various parts of her hold, so as to raise the thermometer to 90° of Fahrenheit; an excellent hot-house was thus formed for the growth of fungus on the surface of the unseasoned timber, and it did grow most luxuriantly.
The oak timber produced in the forests of Germany is remarkably subject to the dry-rot; and it is some little consolation to find that the enemy, in this respect, is no better circumstanced than ourselves. The ships in the Scheldt are known to be in a rapid progress towards rottenness. The Chatham, a 74 gun ship now in our navy, had the dry-rot in her timbers when taken from the stocks in the dock-yard of Flushing: The Rivoli, just off the stocks from Venice, is also infected with the dry-rot. This ship was built of timber from the forests of Dalmatia. Of English oak, that of Sussex is the closest grained and the least subject to decay; hedge row oak, or trees growing singly, less so than trees from the midst of a forest. This too is perfectly consistent with our theory. The more exposed trees are to the wind and sun, the more compact and durable will the timber be, while that from the dense forests of Germany and Canada, into which the sun's rays never penetrate, is more porous, more abundant in sap, and more prone to the dry-rot. We may hence infer the great importance of using only well-seasoned timber in the construction of a ship.
The use of timber of the first year's fall we should most peremptorily prohibit; the vital principle, like that of seeds, will, we suspect, in every species of timber, make an effort to develop itself the first returning spring.
No discovery has yet been made, that we know of, of a speedy method of seasoning timber by artificial means, though numerous experiments have been tried with that view; such as chairing, burne ing, stoving, burying in unslaked lime, or sand, coating with paint, tar, and compositions of various kinds, the effects of which have generally been found pernicious, by tearing the fibres asunder-or. favourable to the progress of decay, by driving the moistu: e into the interior parts of the wood and preventing its escape.
Various attempts have also been made to destroy the principle of vegetation, by impregnating timber with some chemical
preparation, as solutions of green vitriol, arsenic, acetate of lead, alum, &c. infusions of galls, common salt, &c. all of which have failed. We know not if corrosive sublimate has been tried; but we are sure, at least, that it is destructive, both of animal and vegetable life. It is well ascertained by those concerned in alum works, that the timber used in them acquires not only a great degree of du ability, but becomes nearly incombustible. All processes, however, by impregnation are likely to prove too tedious and expensive to be applied ou so large a scale as is required for the tiuber employed in ships of war. Add to this, that all acid impregnations would be destructive of iron, which is but too liable to corrosion by the acid of the woods in their natural state.
Esperiments, we understand, are now making at Woolwich, on the speedy seasoning of timber, by stowing some hundred loads in a close kiln, and introducing, by means of a retort filled with sawdust, an oleaginous substance, which, by insinuating itself into the pores of the timber, as the aqueous or sappy particles are driven off by heat, prevents the fibres from being torn asunder and preserves the logs from cracking. The idea is ingenious, but we augur Do useful results from the experiments themselves. It h::s not been discovered, from the closest inspection, that any artificial process was adopted in seasoning the timber of the Royal William, or any other of our most durable ships; while, on the other hand, the sound state of timber found in old cathedrals, churches and pansions, afier many centuries, affords the most ample proof that nothing more is necessary to secure its durability than proper seasoning, exclusion of wet and damp, and exposure to the common air. The beautiful roof of Westminster Hall is as sound and perfect as on the day it was erected. It is for those concerned in the management of timber to determine what indeed oughtnot, at this late period, to be a subject of inquiry) in what mode the seasoning by a natural process may best be
effected], whether by piling it in stacks, or placing it 01-end under slieds, or strewing it horizontaliy on the ground; by siding or squaring the tree when it is felled, or by leaving the outside or sap, as it is called by the workmen, to protect the more central part from cracking.
It is not enough, however, that the timber which enters into the construction of ships be thoroughly seasoned; it should be kept as much as possible free from moisture. The alternate exposure to water and air, to heat and cold, will sow the seeds of decay in the best oak how well svever it may be seasoned. It would be vain therefore to expect any very protracted period of duration in ships which, while building, have been exposed for four, five, or six years to all the vicissitudes of the weather. Yet this exposure, water-soaked at one season, split by the heat of the sun at another, and the crevices filled with ice at a third, is called seasoning! We should call it AN ADMIRABLE INVENTION FOR DESTROYING OAK TIMBER BY THE common rot IN THE LEAST POSSIBLE TIME; and the fact is that some of the timbers which have been set up the first year, are found so far gone, in the third or fourth, as to make it necessary to replace them with others, less seasoned.* Instead of six years exposure on the stocks, with the bottom of the ship water-soaked in the cavity called the slip, and the upper part splitting in the sun, or cracking with the wind, sir months would be more than sufficient to complete the machine, when the necessary quantity of dry and duly seasoned timber was collected and prepared on the spot. This, however, is not the practice; trees which have been felled a dozen years, and trees which have scarcely left the forest half as many months, greet one another in the same machine. These tianbers are closed
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 which, as it becomes dry, shrinks from its work. Mr. Pering therefore suggests the propriety of building ships under cover.
This is not a new idea. The Swedes build all their ships of war at Carlscrona ja covered docks. The slips in the naval arsenal of Venice are roofed; and the French have a covered dock at Brest. EngHand, the first uaval power in the universe, and equal to all the rest united, is most deficient in proper accommodations for its 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 conveniences due to so magnificent
In the Nelson, a first-rate building at Deptford, some of the timbers
in them six feet long; these receptacles for rain and ice will probably before next sumDer be increased to twelve teet.
a ficet. The expense of a covered dock would be doubly saved in the first line-of-battle ship built in it. The workmen would perform their work sooner and better, because no kind of weather would interrupt their progress. The ship would be caulked, and painted, and coppered when dry, to the exclusion of partial leaks, suffocated damps, and oozing drip.'
But the premature decay in our ships of war is not to be ascribed solely to the state of the timber employed in their construction, nor to their being built in the open air. It is frequently owing to the mode of fastening by treenails, ' a mode,' says Mr. Pering, so objectionable that I defy all the shipwrights in the kingdom, or the art of man to invent a worse instrument for confining the planks of a ship to her side.'* Though not so decidedly hostile as Mr. Pering to this instrument, provided it be made of good sound oak of the same seasoning as the pieces which it is meant to bind together, yet we agree with him in considering it as a very imperfect species of fastening, and highly approve of the substitute which he proposes, namely, a copper bolt, of about seven eighths of an inch in diameter. Its advantages consist
, in the first place, in giving a less wound to the plank and timbers, and thereby allowing a reduction of the scantling or size of the timbers; and, in the second, in giving more security, firmness, strength, and, consequently, durability to the machine. The increased expense, supposing it to amount to £2000 or £3000, or even twice as much, in a line-of-battle ship, is of very little moment, when set against the increased durability of the ship, and, above all, the increased security of her crew.
As we look on the proposed substitution as matter of no inconsiderable importance, we have endeavoured to obtain some accurate information on the subject; the result of our inquiries is as follows: that taking the number of treenails required to fasten a 74 gun ship at thirty thousand, the value of them will be about £800. The weight of copper bolts required to replace them, may be about 45,000 pounds, which, at fifteen pence the pound, would amount to £2,862. This additional weight, which would sink the ship in the water little more than one inch, rould neither impede her sailing, nor injure her stability, as it would be principally below the line of fotation. When the ship, so fastened, is worn out, the original value of the copper cannot be reduced more than a fourth, so that the new ship, to which they may afterwards be applied, will
Treenails, as the word implies, are pins of cleft oak, from an inch to an inch and a halt in diameter, and from a font tu nearly four feet in length, used for fastening the inside and outside planks of a ship to the upright timbers. They have recently been made of American piich pine, a wood more liable to ty-hot and decay than oak, and consequently very improper for the purpose.