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2.4 MARINE REVIEW. = a = —_———- [February 14, CONSTRUCTION OF TORPEDO BOATS AND DESTROYERS. Copyrighted, George Herbert Wilson, 1901. All Rights Reserved. PREFACE. It is not my intention to enter into an elaborate discussion of the entire work covered by the above title, but to compare some of the prac- tical ideas already in use and to deduce conclusions as to the best methods employed; with practice we make perfect, and it is to the practice of the past we must look to make perfect in the future. With this end in view, it seems not an unwise plan to spread abroad some of the work extant— to bring about discussion, and with discussion the natural tendency to- ward improvement along the lines with which we have to deal. To the ship builder, the naval architect, the draftsman, and to the man in the workshop or in the yard, a comparison of the various methods employed in a certain class of ship work is a great help; it tends to bring together the best efforts of ingenious men and inventive minds, evolved in different places and times, into a compact form. This, no doubt, will be a great improvement over the present method, a method which is both tedious and bulky, if carried out properly—I refer to the practice of in- dividual “data-gathering.” This is undoubtedly highly commendable and that man is the most valuable who can command,the greatest amount ol “stored-up” knowledge, together with his professional ability. ; In lieu of this voluminous method, I propose to substitute a single volume. devoted to the best thoughts and efforts coming under my own observation. ‘This will be an incentive for numerous works and criticisms along these lines, out of which will grow the more nearly perfect work of the future. There is no doubt that numerous mistakes have been made and errors committed, not only in the types of boats this volume will treat of, but also in the larger classes, by a lack of comparison and closer investigation of the various methods employed in hull construction and fittings in the ast. ee eee : This country has had the benefit of.the years of experience of Eng- land, France, Russia and Germany, together with the fact of having built nearly thirty-five torpedo boats and sixteen destroyers. This knowledge gained abroad and at home, added to that learned by*the various ma- neuvers and tests as to the efficiency of. all classes, should undoubtedly give us, in the future, a boat unequalled and unexcelled. In this work it is not my purpose to venture into the realm of the designer, or to make suggestions along that line, except as they come in contact, or conflict with, the best methods of construction. The main idea is to bring out the various parts of the boats, as they would appear in the specifications, and treat the methods of construction employed in each individual case. From my personal observation I find that there are varied ideas as to the best methods to employ in the construction of the keel, transverse frames, scantlings, longitudinals and transverse bulkheads, all of which demand the best ideas. In the arrangement of the decks, the disposition of hatches, ladders, lockers and tables; in the proper arrangement of the quarters and living spaces—that part of any ship upon which the critical eye rests—in the most advantageous stowage of movable articles along the upper deck; all of these and more constitute food for the best thoughts and suggestions, and still admit of vast room for improvement.” “With all the foregoing to be thought of and carefully worked out, the smaller, details—fittings which give the finishing touches to any boat—must have ample room for consideration. These details really demand more time and care than those which have been cited, in that they..are so numerous and conspicuous. The hand and awning rails, which can make or mar a boat, the hatch fittings, boat gear, ammunition gear, anchor arrangement, deck and side lights; all these tend to show the amount of care and con- sideration given to their construction. The experienced man will, readily see and appreciate the value of all these points. He knows the numerous critical eyes which will scan his efforts, and he understands with what far-reaching credit a_well- designed and well-constructed boat will endow him, and vice versa. These boats come under the careful scrutiny of the experts of all nations, and as a medium of advertising are unexcelled. Lack of space precludes my citing many instances where notoriety of this character has been gained. When all of these things are taken. into consideration it can be clearly seen that great care, thought and time should be employed in investigations, comparisons.and the like—everything to put a boat before the public and professional-eye which is as nearly perfect as it is possible to make her. ™ §TEM, Although the stem does not enter into the first stages of a boat’s construction, it is placed in the front rank of the items coming under our notice, and it generally precedes all the other subjects in the specifica- tions of boats to be built. In boats of this type, the stem is not an element of any great structural strength; it suffices if it insures local stiffness and makes good connection with the keel and shell plating. The lightest sec- tion possible is generally used. In some cases the entire stem is made of hammered scrap iron, and in others the lower portion is made of cast steel and the two parts scarfed. In the former case the section at the top is rectangular with a rabbet deep enough for the shell plating. This sec- tion continues throughout that portion above the water line and for some distance below it. A gradual increase in width then commences with a gradual decrease in thickness until it makes connection with the flat keel plates, at which point it has assumed a flat, broad section, taking the shape of the keel plates. The same sections are used in the latter case, except in the lower portion, which is made a little thicker and heavier. This method has the advantage of being cheaper, as it does not require a difficult forging, the upper portion of the stem being made of a rolled bar and the lower part a steel casting. In the earlier’ types of boats built, the turtle-back deck was an im- portant feature, and»still remains so in some of the later destroyers. In some. of these: cases the stem stops at the under side of the deck plating, but im others it extends above the deck and a small bulwark is carried aft from it about 3 ft. This bulwark has no special advantages, but has some great disadvantages, one of which is the difficulty of fitting.a suitable hawse pipe to obtain a straight lead for the anchor. hawsers and towing lines. .” Note—The author is indebted to Joseph C. Wilson for the accompanying sketches. These difficulties are important enough to warrant an extensive inves- tigation as to whether they cannot be overcome and a better arrange- ment devised. In the boats having the stem stop under the turtle deck a very Satisfactory scheme, although far from perfect, was employed to overcome these difficulties. On top of the stem was fitted a composition casting with palms extending back on the deck and down on each side to connect with the shell. The casting was made in the shape of a circular hawse pipe with a bell mouth on the forward side. The hole was made large enough to allow two anchor or towing hawsers to pass through. This method, although answering the purpose, is considered by some rather a makeshift, and is not deemed sufficiently strong in its con- nections to the surrounding structure. The connections to the shell and deck are not very extensive, and to make them so a great increase in weight would be entailed, besides having a very bulky casting. _ To obviate this and to meet the various conditions, I would call atten- tion to sketch No. 1, in which I propose to practically embody the above ideas in the stem itself. From a glance it will be seen that the stem forms the main support of the bow casting, with the deck and shell con- tributing a supplementary support. This casting to extend down on both sides of the stem for a distance of about 5 in. and to be well riveted to it by countersunk head and point rivets. The casting will conform to the shape of the stem, rabbet included, thus insuring no additional expense in the forging. It will be noticed that the casting is made of sufficient thickness to secure ample stiffness and strength. The main portion is car- ried back of the stem and at that point is reduced in thickness, extending (as shown) inside of the shell and under the deck plating. The connec- tion to the shell and deck are made by rivets where possible and by taps elsewhere. ‘ The sketch shows the upper part of the casting hinged to facilitate the entering of hawsers, cables, etc., and adds much to its value. The hinging can be done from either side, as it is merely a question of remov- ing a countersunk toggle pin. As both sides are made up of a Series of lugs working on a 34-in. pin, the strength is well maintained. The hinged part, having little or no wear upon it and taking very few of the strains, can be decreased in thickness, as shown. On the upper half is shown a socket to receive the flag staff or rail connections. The reasons for elaborating on a detail of this character are sufficient to warrant it. It was learned by experience during the Spanish war that some of the boats, when at anchor in a seaway with the wind blowing in one direction and the tide rurning another, were all the time troubled, either with the anchor hawser crossing the bow or being nipped at the fairlead in the bulwarks. One of the boats lost two anchors in a single night by having her hawsers cut from this cause, although only a moder- ate breeze was blowing, with very little sea on. ae STEM, KEELS AND LONGITUDINALS, As everything must have a beginning, the most natural part of a boat to comment upon at the outset is her keel, stem and stern. The keel, an important element in the structural strength upon which so many of the longitudinal strains are borne, must necessarily demand considerable at- tention. To know the best mode of construction a proper idea of its fune- tions must be had. It is without doubt one of the principal members of almost any equivalent girder,,both from the proportion of metal involved and from its extreme distance from the neutral axis. It is obvious there- fore that the boat, having longitudinal strains such as are prominent on the crest of a wave, in the hollow thereof, or under the varying conditions of speed and stress of weather, is dependent upon the keel and its adjacent members to bear the greater part of the load. : It is understood, of course, that in the design of the keelsons of a boat the strains to be borne by the transverse framing must not be overlooked. The ideal condition must be arrived at in outlining its construction. The severest strains, however, to which ships are subjected are those tending. to produce longitudinal bending, and therefore the greatest strength is required to prevent change of form in that direction. The sketches shown below will give some idea of the various methods employed to gain the above ends. By taking each sketch and dissecting it the best results of comparison can be obtained. It will be seen by, ref- erence to. sketch “A” that the intercostal style of keelson was e ployed in the construction of this vessel. This method allows continions foe and transverse framing to be used, but seriously undermines the longitudinal strength. Intercostal work, whether it be keels or longitudinals, cannot be depended upon to be kept in a true line, unless some one of its mem- bers be made continuous.. This must be done or else the work must have the most careful attention to secure proper alignment. ‘This latter condi- tion cannot be obtained in every ship yard. If the alignment be-at all out