AMERICAN CLASSIFICATION OF AMERICAN VESSELS. 



By W. A. DoBsoN, Esq., Vice-President. 



[Read at the twenty-ninth general meeting of the Society of Naval Architects and Marine Engineers, held 



in New York, November 17 and 18, 1921.] 



CLASSIFICATION OF VESSELS A NATIONAL ASSET. 



Classification of vessels built for the merchant marine is fundamentally a matter of 

 national importance. This view is justified by the fact that the certificate of class issued by 

 a registration society is a guarantee that the vessel so classed is properly constructed. Such 

 a certificate assures the owner and the insurance underwriter that the strength of the vessel 

 is unquestionable and that its character of construction is in accordance with the standards 

 of the classification society. The enormous risk, therefore, incidental to an inferior construc- 

 tion is eliminated, and only the hazards common to sea service remain to be considered. 

 The result, therefore, of building to the rules and survey of a classification society, in so 

 far as providing for and obtaining a proper construction goes, is the assurance that the lives 

 of those who travel by sea, in vessels so constructed, and the vessels themselves with their 

 cargoes are to that extent safeguarded. Life and property, so safeguarded, become a part 

 of the nation's assets. 



OBJECT. 



The purpose of any society for the registration of vessels is to classify them in accord- 

 ance with their strength and seaworthiness, with proper regard, on the one hand, for the 

 safety of life and property, and, on the other, to obtain the necessary strength and seagoing 

 qualities without impairing the earning power of the vessel by carrying around for its life- 

 time an unnecessary weight of structure that reduces the cargo-carrying capacity. It would, 

 then, appear that, among other responsibilities, a moral obligation rests upon the classification 

 society, as representing the owners, to use every endeavor to prevent the incorporation of 

 unnecessary weight, thereby assuring a vessel of the maximum earning capacity combined 

 with satisfactory strength. From the time of Noah to within the last two centuries, vessels 

 were constructed either by inspiration or from experience gained by a long series of obser- 

 vations on vessels built from prototypes, whose characteristics, good and bad, were carefully 

 noted and incorporated or eliminated, as the case might be, in following designs. 



STUDY OF STRESSES ON FLOATING STRUCTURES. 



With the introduction of iron as a building material, it became practicable to consider 

 the hull proper as a girder and to closely approximate the stresses brought upon a vessel 

 floating in a highly disturbed medium. The art of arranging the scantlings for safely meet- 

 ing such stresses became the study of naval architects of all nations, and, while new combi- 

 nations are constantly being developed, the general principles involved are well known and 

 carefully considered in any standard arrangement of scantlings. As a result of such inves- 

 tigations, combined with many years of sea experience, tables or rules have been prepared by 



