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August, 1917 are necessary in her hour of trial by battle. This is rendered possible only by the most perfect means and instru- ments of communication throughout all parts of the vessel. These sys- tems of communication must be such that they will not break down in the midst of the noises and confusion of battle, or because of the high mental tension, at such times, of the per- sonnel using them. The sciences of physiology, medi- cine, and hygiene must likewise play their parts, for, during the long years of peace, each of these vessels must be the healthful and, as far as possi- sible, the happy home for anywhere from 1000 to 1500 men. This means that what we term in the navy “berthing and messing” facilities, or what in civil life would be referred to as the “housing and feeding” con- ditions, must be based on the most modern scientific principles. Like- wise, to insure efficiency in battle, the design must take careful cognizance of what these sciences have taught us as to the limitations of human en- durance when working at high pres- sure under adverse conditions. Nor do we stop at this point, for there is provided, in addition, a completely equipped medical establishment or hospital, including operating rooms, isolation wards for contagious dis- eases, special examining and_ treat- ment rooms, dental facilities, etc. Branches of Naval Architecture Without further enumeration of the many other branches of science and engineering which necessarily enter into the design of one of these great ships, let us consider more _ closely the principal branches of naval archi- tecture proper. This is, broadly speak- ing, the division of engineering which enables us to make use of accumulated progress and knowledge to produce one workable and efficient assembled unit in. the form. ofa ship...‘ its branches closely parallel the primary operations necessary in the design of such a ship, as has been described. Given the fundamental requirements of the design, which in the naval serv- ice we term military characteristics, and which consist of a brief state- ment of the results which it is desired to obtain with the completed vessel in service, it is first necessary to make an estimate of the size of the ship which will permit a solution of the design problem. The first esti- mate or approximation must be based largely on previous practice and ex- perience. Before the development of naval architecture, in its modern sense, the necessity usually involved rather slow’ step-by-step progress from one ship to another. Naval architecture has now taught us how to make these steps much greater, THE MARINE REVIEW so that during the last quarter of a century advances whicH would have been bold to rashness at an earlier time have become almost routine. The rule of step-by-step progress referred to above has at least one remarkable—we may almost say astonishing—exception. Some 65 years ago a famous English civil engineer and bridge builder turned to ship- building. Maintaining that the larger the ship the more economical and efficient her operation, Brunel attract- ed large capital and in association with Scott Russell, the shipbuilder and naval architect, finally produced the Great Eastern, which was indeed a giant by a pigmy when compared with the other iron steamships of her day. Her keel laid in 1854, launched in 1858 after many difficulties, and put in service in 1859, the Great. EASTERN was not a commercial success. She fell short, of the expectations of her de- He Designed Our Battle Fleet Rear Admiral David Watson Taylor presented the accompanying paper before the Franklin institute a short time ago, just after he had received the Franklin medal. He was awarded the medal “in recogni- tion of his fundamental contribu- ‘tions to the theory of ship resist- ance and screw propulsion, and of his signal success in the application of correct theory to the practical design of varied types of war ves- sels in the United States navy.” Admiral Taylor is chief constructor and chief of the bureau of con-' struction and repair of the United States navy. signers in many respects. The success- ful completion even in five years of such a vessel was truly a remarkable accomplishment, but her size was ahead of her day, and it was not until 1899 that we find it again reached. As already stated, progress is more rapid nowadays than heretofore, but even now naval architecture would hardly enable us to take, with confidence, such a leap as the Great EASTERN promoters un- dertook. Ship. Strength and Stability When in the early stages of a de- sign we have, based on previous prac- tice and experience, reached a first approximation to the size of the ves- sel, it is next necessary to examine in detail the problems of strength, stability, resistance and propulsion of ship. These, represent broadly the main divisions of our subject. Naval architecture, as a whole, and _ its branches, like engineering generally, has not yet become an exact science, and in some respects it appears im- 269 possible that this will ever be at- tained. The strength and stability of ships, for example, should be such as to enable them to withstand, ‘under all conditions, the waves of the sea, but the latter are infinite in variety, and the attempt must be to provide for any manifestation arising from this variety. It is, therefore, not pos- sible in a new problem to lay down an exact condition of water surface, and say that if our ship can stand this condition it can stand all others. The best we can do is to make an approximation of the most severe con- dition, based on previous accumulated experience and observation. There have been made many thousands of observations on sea waves, but there is yet no complete agreement in re- gard to their limiting characteristics, such as length, height, and the rela- tions existing between these dimen- sions. Theory of Wave Formation About the middle of the last century Rankine gave us the. first complete mathematical theory of the .forma- tion and character of waves, known as the trochoidal theory; his result had, however, been largely predicted by Grestner more than 60 years be- fore. Although Rankine’s theory does not explain and is not entirely consistent with all phenomena of this nature, it is generally accepted today as a reasonable and convenient ap- proximation of the facts, and it is usually upon stresses due to waves such as result from Rankine’s theory that we have our determinations of strength of vessels. We find that from the very be- ginning of practical shipbuilding the problem of strength was recognized in concrete form, for in the very first ship of which we have historical record its picture shows what we now term a “hogging” girder, which was provided to take the strains re- sulting from the variation between distribution of weight and distribu- tion of buoyancy. It was the exist- ence of these strains, and the fact that they increased with increase in length of ships, that operated to limit the length and consequently the size of ships during the era of wooden shipbuilding, as it was then, and still is impracticable to develop the full strength in end connections between contiguous wooden members. The introduction of iron and steel, in conjunction with the development of methods and mechanisms for riveting, has made the modern ship possible. For many years the provision of the necessary strength depended largely on rule-of-thumb methods and step-by-step development from one