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» large English fleets of steamers, of which - over twenty percent. had been lost at sea . in the course of a few years and were never | a bev oqre BOI oo a Png ge. ee Db. TO -COMMERCE, > VOL. V.NO 7. .COMPOSITE SHIPS. ‘ Cuicaao. Feb. 13, 1883, Editor Marine Record: . In my last letter I quoted some opinions from the engineer, Norman B, Wiard. Re- ferring to sea-going ships, heAtated. as his conviction that well built “woodén ships _‘‘would outlast those built of iron, arid not be so liable to sudden disaster, A ship might be in commission for years before encoun- tering an extraordinary gale at sea, butif inion, her sides must be frequently subjected to the strain of uneven expansion and con- traction, cutting and loosening rivets, and bursting off rivet heads, until, when finally. subjected to the great strain of a heavy gale, and correspondingly wild and heavy seas, the seams, so weakened, wonld open and the ship suddenly founder. He instances two heard from. : One summer he visited Montreal to ob- serve the effect of change of temperature on .the Victoria tubular iron bridge. ‘The cen- ter apan,430 feet long, would lengthen about six inches between midnight and noon. One end was stationary and the other rested up on rollers, 80 that it could move on them as it expanded and contracted. A man was always on hand to keep the railway tracks continuous by inserting short pieces of rail to fit the gaps as they opened or closed. In the forenoon when the sun shone on one side of the middle would sway toward the gun six to seven inches beyond its true al lignment. The same would occur on the other side in the afternoon. At noon. when the sun shone on the top it would crowd upward in the same proportion. ‘There were no wide extremes of temperature—only the range between a summer night and a sum- mer day, and between. the sunshine on one side, and the shade of the structure on the opposite eide. In view of these facte, what must be the strain upon the half submerged aides of an fron steamship passing suddenly out of the Gulf Stream, where the tempera- ture of the water is about 80 degrees, among iceberge, where it is below 40 degrees? Or coming upon the coast off New York, where the temperature of the water fe about 45 de- grees, and the mercury exposed to the air stands at 20 to 80 below zero? ‘I'he ship’s bottom is in one fluid and the top in another, differing in temperature 46 to 75 degrees. ; ‘There can be no uniform graduation ot ex-! Conceive what must be the strain upon the plates and rivets along this line. LIwagine the deterioration of iron or steel plates, the utting and loosening of rivets and bursting off rivet heads: under such a tremendons strain. Similar experiences must happen frequently to any steamship navigating the ocean, especially on the routes between British and American ports. ‘Ihe deteriora- tion of iron vessels from this cause is not so apparent as their want of logal strength, ex- hibited in the recent appalling disasters in the Irish and north seas, but muny. times more fatal, and is constantly at work, like worms at the root of a: tree, or tubercles in the lungs, that sap away the life in darkness and silence. | they are not likely to abandon it. To do so would beto abdicate their maritime suprem- acy. But the case is different with us. We have no marittme supremacy to abdicate. Our greatness in that direction, as compared to theirs, is to be achieved—or rather—-re- gained. We canonly regain what we have lost by inventing some means to wrest it back from the hands them that. won it from us. It is conceded that we.cannot compete with them in the construction of iron ships, under the most favorable legislation consiat- ent with the interests of the nation at large, so long as there is such a disparity as now exists in their favor in the price of labor, ‘The only probable remedy would be worse than the disparity itself—namely, the reduv- ie of wages in this country to their stand- ards. We can only compete with Englishmen in the foreign) carrying trade by building another kind of vessels that will carry ag much as their fron vessels, be as durable and more geaworphy, and cost less to construct If we can do this, there can be no doubt about our success. When Mr. Wiard predicted that the com- site ship would be the ship of the future, be anid the present syatem of building them was defective, and a new and better system would be invented. It is clear that the prin- cipal defects \n the present system are lack of sufficient rigidity of structure, resulting from the narrowness of the outer frame faces with no compensating device for stiffening, “ENG CLEVELAND, O., FEB. 47 4883.. row fore and aft strip midway of the ‘sides, | defevt is too much cutting away and weak- separating this wide range of temperature.| ening of the: plarks by the large holes for the heads of the bolts, sunk deep enough to plug. If these and some minor defects can be. remedied, without adding to the Very durable, burden- some and economitcal composite vessels can be produced. A’ new system of composite ship duilding has recently been invented, which, it is claimed, will not only remedy all these defects, but will also materially reduce The English have made tron shipbuilding an apparent—perhaps a real success, to them at least it has thus far been the latter—the stepping stone to their present miritime Rrenvneans and: whatever the future may jiselose regarding. its economic character, BP Fige es weight ‘and coat. the cost of construction. In_ this new. style, ‘The transoms and keelsons curely bolted to it. The reverse angle bar ia separated trom the outer bar far enough ontside the floorhead to be raised so as to cover its upper cqrner for a sufficient length of lap, be let flush into it and cross-bolted through face and tlang. The canv frames are all of metal, tastened to wooden ¢ant heels bolted to the deadwoods. The fantail frames are of metal and are bolted directly to the curved extension of the stern post. The deckbeams are of metal, gussetted and riveted to the body trames the same as the iron vessels. ‘The whole frame above the whole frame above the floorheads is similar to that.of an iron vessel, and the bottom, part like that of the wooden vessel. It is susceptible of being corded and braced to any desirable extent, with tron riveted to iron so securely that ary amount of strength and stability can be obtained. The methods of putting in planking and waterways, how- ever, are such that no metal cords or braces are required in vessels of moderate size. ‘The outside planks in small or medium sized| vessels, where no cording and bracing are used in the frames, are about 50 per cent. thicker than those of wooden vessels, and abont twice as thick as the center line of the bilges, diminishing gradually each way to the thickness of the aide and bottom Janke, ‘They are fastened to the floor tim- ra with spikes, bolts or treenails as in wooden vessels, and to the metal parts of the frames with thick, square headed wood bolta, thrust from the inside throngh holes pansion and contraction here, as in the case and want of firmness in the bolting of *the| in the frames, and turned with strong socket of the Victoria bridge tube, but only a nar-» planks to the frame. Another important wrenches into holes bored for them from the the keel, stem apron, stern post, and deadw are of timber. ay be either of timber, which is the cheapest, or of metal, ‘The frames, except cants, are each in three sections—the flooring of timber in one piece, or flitches in single lengths ‘across the bottom, or built up of shorter pieces—and the side sections from the floorheads to the top, of) metal, made of angle’ bars like the frames of iron vessels. ‘Nhe outet angle bar laps several feet upon the side of the floor timber, flush with its lower edge, and is se- INEERING AND SC / Annum. i Sivoue Corims } Cuwss. insidé, about three-fourths the | distance through the planks. These bolts are thick- ened a little. just under the heads, so as to ffl ‘the holes in the frames tightly when turned home, The outside surface of the planking shows no fastening, except in the wake:ot the, waterways. ‘The planks are edge-bolted from the floorheads to the tops of the sides—except near the wood ends— one bolt vrossing each seam at each frame space. The planks are butted between the metal frames, and the butt seams dre bottomed with treenails, There should be an edge- bolt on each side near the butt, driven through it and’ the plank above and balf throngh the one’ below. Greater strength of side will be secured Li extending metal frames and édge-bolted planking up to the main rail—the metal frame tops an- swering for bulwark stanchions. ‘The’ waterways are built of several strakes of planks set on edge, or long square scant- lings, properly shifted with each other and the collatteral gunwale planks, bent around the bow—also the stern if round-fastened to the deckbeams with wood screw bolts trom underneath, and to the sides by long bolts driven from the outside through all the strakes and blocks of timber that fill the in- tervening spices between the frames, and forelocked upon the face of the inner strake. The keelsons, if of timber, are fitted like those in wooden versels. Bilge keelsons, except as those in parts of a set.of wing keelsons, are rendered superfluous by the thickness of the outside bilge planking, and the double fastening at the frame laps. In vessels deep enough to afford the space re- quired, the tops of the main and wing keel- sons should be upon the ‘same level, so that the floor ceiling may be laid flat over them all—thus enhancing the safety of the cargo against damage from bilge water, and the convenience of handling it. The hold stanchions should be strongly fastened to the main keelson and to the beams of each deck—thus giving the sup- portof all the beams to the ship’s bottom. The ceiling is not relled upon for addi- tional strength of structure, as in wooden versela, and may therefore be composed of . light and cheap materials, having only 3uf- ficient strength to resist the weight and abrasion of cargo. A very cheap, durable and water tight ceiling may be made of two courses of common pine boards, interlined with several plies of common roofing paper. The sides, edges and ends of the boards and each plie of the paper should be painted with Continued on page 4,