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28 Ww A. RO NE Pert oy oe Rook ¥ I E W _ Experimental Tank for Research Work on Ship. Propulsion." : BY SIR WILLIAM H. WHITE, Vice President of the Institution of Naval Architects. At the request of the council, I have undertaken to submit to the members of the Institution a proposal for the estab- lishment of a national experimental tank, to be chiefly de- voted to research work in connection with fluid resistance and ship propulsion. "Having been intimately connected with the work of the admiralty experimental tank for more than thirty years, from the time of 'its establishment by the late Mr. W. Froude, and having also full information as regards the nature of the work which has been done at the experimental tank established by Messrs. Denny about twenty years ago, and the similar estab- lishments founded by Dr. Tideman in Holland, by the Russian government at St. Petersburg, by the Italian government at Spezia, and the United States government at Washington, as well as knowing generally what has been done by the tanks established at later dates in Germany, and what has been done or is now contemplated in France, I am in full agreement with the view that it is not wise to contemplate the establishment of a single tank in any locality to be available for the testing of ship models in connection with designs. 'The inevitable consequence of a fuller recognition of the value of these tanks, as adjuncts to the designing departme.ts of ship yards, must be the establishment by each of the great firms of its own experimental tank. Messrs. Denny set the example twenty years ago. Messrs. Brown have lately done the same thing on a magnificent scale at Clydebank. Mr. Parsons, at an earlier date and in a simpler form, devised and carried out most ingenious arrangements for testing resistances of models of his turbine-propelled vessels. What these firms have done is what will almost certainly be done on a larger scale in the immediate future. There are openings no doubt, and it is surprising to me that they have not as yet been availed of, for the creation in or near ship building centers of experimental' tanks, possibly of less elaborate and costly nature, under the control of gentlemen of ability and high character; whereat models may be tested of ships pro- posed' to be built by firms--not of the first rank, and whose needs in regard to novelties of form or propulsion are only occasional. Even in' ordinary practice cases occur where ship builders have to face new or critical conditions, and where model experiments would be of the greatest assistance. It.is the fashion, I know, to treat the design of 'cargo steam- ers as a department of ship huilding where only precedent and experience are of importance, but those concerned with that branch of construction realize how often, when difficult problems are propounded and there is little choice in the selection of some or all of the principal dimensions, they would be glad to turn to authentic experiments on resistance, and so to eliminate some of the features in designs which now have to be dealt with as best they may, without scientific guidance based on experiment. Many builders of small craft also, whose establishments could hardly bear the burden of an experimental tank, would be glad to patronize such experi- mental establishments to have been indicated. Having said this, may I add an expression of my profound conviction. that, if the ship builders, marine engineers, and ship owners of this country are well. advised, and desire: to further to the utmost the maintenance of our. supreme posi- tion in mercantile ship construction, they will not be slow in responding to the appeal which is now made, and in providing the funds. necessary for the establishment and maintenance, in. connection with the National Physical: Laboratory, of a tank avowedly devoted to research work on the general prin- ciples of fluid resistance, the efficiency of propellers, and oth- *Paper prepared for Institution of Naval Architects. er matters greatly influencing economy of propulsion. Gener-. osity in this instance will undoubtedly result in a rich reward. _ The questions which might be dealt with in such an estab- lishment are of universal interest to all classes. connected with shipping. Ship builders and marine engineers, no doubt, would thus derive much benefit; but the greatest gains would. be realized by ship owners, whose working expenses would be minimized by improvements resulting from experimenta} investigations, conducing to lessened resistance or greater propulsive efficiency. Moreover, in the competition with foreign designers, which: grows more and more keen as their experience is enlarged, we cannot afford to throw away any aid to excellence in design, and must apply scientific methods to the fullest possible extent. It is a suggestive fact that a great shipping corporation like the North German Lloyd have thought it worth while to establish and maintain an experi- mental tank at Bremerhaven, and it is within my knowledge that very substantial improvements have been made in con- nection with the designs of their ships as the result of in- vestigations there carried out. No doubt, as the number of experimental tanks belonging to private firms is increased, the testing of methodic series of models (representing variations in form on certain principal dimensions, or alternative dimensions and proportions on given displacements), inquiries into the efficiency of propel- lers, investigations of frictional resistance with different natures of surface, and other matters more or less belonging to general research, will be dealt with more exhaustively than has hitherto been possible. On the other hand, those. of us who have watched the working of these establishments for many years know that if they are engaged, as they must be to a very great extent, in testing models for current designs-- involving the trial of a number of alternative forms or differ- ent propellers--such great demands are made upon the time and working capability of the staff that it, is most difficult to carry to completion any elaborate investigation. More or less serious interruptions growing out of pressing demands continually occur. The attention of the staff is frequently diverted from problems incidental to original research, in- volving close observation and thorough analysis, and, in this way, the results obtained are much less satisfactory, while the investigations. are more prolonged. In not a few in- stances special apparatus has to be devised and installed for the conduct of experiments on special subjects; and sometimes it has to be dismantled, to a certain extent, in order to permit ordinary model experiments of a pressing nature to go forward. Mr. R. E. Froude can tell us how greatly unavoidable in- terruptions of this nature have interfered with methodic re- searches on ship forms and screw propellers, which were initiated by his father, and which have been continued and greatly developed by himself during the long period that he has so ably directed the admiralty experimental establishment at Haslar. The enormous development in the fleet in recent years and the great variety of designs of ever-increasing speed and size, have resulted in the practical absorption of the experi- mental staff in the current work incidental to the designs for his majesty's ships. Indeed, since the death of Mr. W. Froude, when the experimental establishment was transferred to Haslar from Torquay, it has become an integral part of the constructive department of the admiralty; and it was my duty as director of naval construction to consider its most effective organization on that basis. Mr. William Froude proposed his system of model experi- ments in 1868, in connection with the report of a committee ap- pointed by the British Association, and his experimental tank