918 



HYDRODYNAMICS IN SHIP DESIGN 



Sec. X5.3 



TABLE X3.e — Mass Density of SALT WATER, 3.5 Per Cent Salinity, Embodying Variation With Temperature 

 The values given are in English engineering units of slugs per ft'. They correspond to those adopted by the American 

 Towing Tank Conference in 1939 and published in SNAME, 1939, p. 416. To convert them to pounds weight, multiply 

 by the local acceleration of gravity g. 



spending data for salt water of specific gravity 

 1.024, as used by D. W. Taylor in his books and 

 by the Experimental Model Basin [C and R 

 Bull. 7, 1933, pp. 18-19]. 



Table XS.c lists the data used by several 

 model-testing establishments in North America 

 for model- basin water at a temperature of 68 

 deg F, 20 deg C. 



X3.3 Mass-Density Values of Fresh and Salt 

 Water, in English and Metric Engineering Units. 

 Values of the mass density p of both fresh and 

 standard salt water, as adopted by the American 

 Towing Tank Conference in 1939 and pubHshed 

 in SNAME, 1939, page 416, are presented in 

 Tables X3.d and X3.e, respectively. The values 



for salt water are derived from experiments with 

 actual ocean water as contrasted with previous 

 tables based on sodium-chloride solutions 

 [SNAME, 1939, p. 418]. The p-values are in 

 EngUsh engineering units of slugs per ft^ and 

 cover a range of temperature, 32 deg F through 

 86 deg F, nearly as large as that encountered in 

 the various waters of the world. 



The slug of mass in the Enghsh system is the 

 mass to which an acceleration of one ft per sec^ 

 would be given by the application of a one-pound 

 force at a given point on the earth. To convert 

 the values of mass to those of weight at any 

 point, multiply by the acceleration of gravity g 

 at that point. The values of g at sea level, for 



TABLE X3.f— Mass Density of FRESH WATER, Embodying Variation With Temperature 

 The values given are in metric engineering units of slugs per meter'. 



There are given hereunder the gravity constants or values of the acceleration of gravity g, in centimeters per sec^ 

 for sea level at six values of latitude. These data apply also to Table X3.g. 



15 deg 

 978.428 



25 deg 

 979.004 



35 deg 

 979.780 



45 deg 

 980.665 



55 deg 

 981.551 



65 deg 

 982.332 



