920 HYDRODYNAMICS IN SHIP DESIGN Sec. X3A 



TABLE X3.i — Kinematic Viscosity of Fresh and Salt Water, in Metric Engineering Units 

 The values listed are for (lO^);- in meters^ per sec. The salinity of the salt water is 3.5 per cent. The fifth significant 

 figures in this table are somewhat doubtful. 



six values of latitude, are given as part of Table 

 X3.d on page 917. 



For calculation of the acceleration of gravity 

 at any point, H. Rouse gives, for English engi- 

 neering units, the empirical relationship 



^(in ft per sec^) 



= 32.1721 - 0.08211 cos 20 - 0.3/1(10"=) 



where ^(phi) is the latitude in deg and h is the 

 elevation in ft above mean sea level at that 

 latitude [EMF, 1946, Eq. (233), p. 358]. 



Tables X3.f and X3.g present the values of mass 

 density p for fresh and salt water, respectively, 

 in metric engineering units, for the convenience 

 of those using this system. 



The slug of mass in the metric system is the 

 mass to which an acceleration of one meter per 

 sec^ would be given by the application of a one- 

 kilogram force at a given point on the earth. 

 Values of the acceleration of gravity g at sea 

 level, for six values of latitude, are given as part 

 of Table X3.f on page 918. 



X3.4 Kinematic-Viscosity Values of Fresh and 



Salt Water, in English and Metric Engineering 

 Units. Values of the kinematic viscosity j'(nu) 

 for both fresh and salt water, expressed in Enghsh 

 engineering units, are set down in Table X3.h. 

 These values, based on sources available in 

 September 1939, were adopted in that year by 

 the American Towing Tank Conference and 

 published in SNAME, 1939, page 417. 



The fifth significant figures in this table are 

 doubtful. 



The English values of Table X3.h were later 

 converted to metric engineering units by H. F. 

 Nordstrom and other members of the SSPA staff 

 in Goteborg and pubhshed in SSPA Report 18, 

 1951, page 6. These metric values are set down 

 for convenience in Table X3.i. 



X3.5 Other Mechanical Properties of Fresh 

 and Salt Water at Atmospheric Pressure; Dy- 

 namic Viscosity and Surface Tension. Tables 

 X3.d through X3.i preceding list the mass den- 

 sity p and the kinematic viscosity v of fresh and 

 salt water in a limited range of temperature, such 

 as is encountered in the oceans of the world. 



