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382 THE MARINE REVIEW Shipbuilding of Yesterday and Today By Georce LESLIE. (Reprinted from Cassier's" Magazine.) N no branch of human effort have greater strides been made during the last three decades or so than in ship construction and design. Thirty years ago iron, which had previously supplanted wood as a_ shipbuilding medium, and itself 'brought radical - changes, was on the eve of being dis- placed by the subtler material, mild steel, with its greater tenacity, less comparative weight and wider useful- ness. The completeness of the surrender of iron to steel is forcibly brought home by the fact that the iron to be had so plentifully when the demand was great cannot be bought now. Material there is of the name, but take a sample and compare it wth a piece broken from a hull discarded after thirty-five or forty years' useful service. Inspection and mechanical testing alike prove the older material to be superior. It is not, of course, that metallurgists are less ingenious 'than formerly; but that iron, having served its day and proved a stepping- stone to higher things, no longer claims the attention it did, and conse- quently tends to fall in quality in keeping with its reduced importance as a constructive element. Possibilities of Mild Steel. _It is not too much to say that the advance in shipbuilding since the in- troduction of mild steel 'has (been greatly helped by the possibilities of that material. Particularly has this been so in matters of detail--and ship construction is made up of details. Since every joint in a structure is potentially a point of weakness, and as steel plates can be manufactured longer and wider than iron plates, an early improvement was effected by re- ducing the number of joints. Then the form of joints was dealt with, overlapped end joints being substi- tuted for those of the less efficient and more expensive butt or flush type. It is only fair to acknowledge that the overlapped end joint, though admitted an improvement in construc- tion, was objected to as unsightly and as increasing the resistance to the motion of the vessel. But by fitting the plates with the exposed ends look- ing aft, the latter drawback was mini- mized, and custom has long since reconciled us to the former. Other modifications of compara- tively recent adoption directly trace- able to the superior ductile qualities of steel are the joggling of plates at the edge jo'nts, particularly those of the shell; also the scarphing of «the end joints for the 'breadth of the edge laps, thus avoiding the use of packing pieces, saving weight and im- proving the construction. Then there is the flanging of plates to form right-angled joints and bulkhead stiff- ness, as against the fitting of angle bars, economical improvements clear- ly, though opposed by some builders on the ground that the loss of stiff- ness due to the omission of the rolled ibar is not made good by merely deep- ening the web slightly, as is usually done. Structural Ballast "Tanks. The introduction of structural bal- last tanks is to be included in the chronicle of progress, although it is something of an old story now. The first ballast tank was, of course, a rather crude affair. First steps are usually tentative, and this was no ex- ception to the rule. We have no in- tention, nor is this the place, to de- scribe the schemes 'proposed and adopted from time to time for the conveyance of water ballast; but a comparison of the earliest water bal- last tank with the latest affords no bad illustration of the skill and. in- genuity which have 'been brought to bear upon ship construction in mod- ern times. The writer thas vivid recollections of the first vessel built with an inner bottom having the frames cut at the bilge which came under his notice. This is a story of twenty-five years ago, and tanks so built were very few. It was the first attempt of the firm concerned. Well, the manager and foremen carefully considered the matter, and concluded that the only way under the circumstances to keep the 'hull fa'r was to erect the frames complete from keel to gunwale, fair the body, and, after carefully shoring and ribbanding and_ taking special precautions to prevent movement at the .parts affected, to cut the frames on the stocks. This was done, and the job was, of course, a splendid one; but the cost was considerable. Contrast this with the modern method of construction, in which the fram- October, 1909 ing is done piecemeal and the inner bottom is framed and even plated before the structure above the bilge is started with. ing a shipyard is familiar with the long, skatelike body of the completely framed ballast tank- and inner bottom, which, as it lies on the stocks, looks like anything other than a ship. Doubling the Vessel's Size. Important departures in ship evo- lution have also been due to the de- mands of commerce and the con- tnual striving for economy forced on owners by the keenness of modern competition. It was quickly seen that doubling the size of a steamer need mean little increase of crew or work- ing expenses, and so large vessels be- came the order of the day. Again, the demands of owners for improved stowage facilities, and for vessels suitable for special trades, led to the suppresion of lower decks, tiers of beams and ranges of pillars--modifi- cations, now. that they are accom- pl'shed, which seem simple enough, but which called for the exercise of much skill and scientific ability, since the standard of structural strength had to 'be preserved. All this should be borne in mind when reckoning up the progress of the years. Turning to design, we find devel- opments no less remarkable. In gen- eral appearance sea-craft are much changed--it must be admitted, in Some respects not for the better. Cargo steamers, particularly, have de- generated in outward form. They are clumsier, more angular, less graceful, than formerly. One looks in vain in our 'waterways for the clipper bows, takish masts and trim sails of the early traders. The changes which culminated in the "tramp" of to-day came gradually. First the masts, al- ready reduced in number, size and importance by the supersession of steam over sail power, were stripped of yards and square sails, and later of trysails, in some steamers not even a staysail beng carried. Now, alas for sentiment! masts are frequently fitted without rake; and gawky a ship so fitted looks alongside those of the older style. But a raked mast is a bad derrick post, and efficiency first, appearance last, is the present rule. Changes in Appearance. Even standing rigging, with its con- venient rattlins, beloved of the youth- ful mariner, is disappearing in favor of the widely-spaced guy ropes, a prosaic iron ladder riveted to the mast, giving access to the masthead. Everyone frequent- : x ; 3 ; § '