PRINCIPLES OF NAVAL ENGINEERING 



Table 7-5. —Selected British-Metric and Metric -British Conversions, 



TYPE OF 

 MECHANICAL BRITISH-METRIC CONVERSIONS 

 UNIT 



METRIC -BRITISH CONVERSIONS 



LENGTH 1 inch = 2. 540 centimeters 



1 foot = 0. 3048 meter 

 1 yard = 0.9144 meter 

 1 mile = 1.6093 kilometers 

 1 mile = 1609. 3 meters 



1 centimeter = 0. 3937 inch 

 1 meter = 39. 37 inches 

 1 kilometer = 0.62137 mile 



AREA 



1 in. 



6. 452 cm 

 2 



1 ft = 929 cm 



1yd" 



1 mi^ = 2. 59 km 



0.8361 m 

 2 



100 mm = 0. 15499 in, 



100 cm^ = 15.499 in, ^ 



100 m^ = 119,6 yd^ 



1 km 



0. 386 mi 



VOLUME 



1 in, - 



1 ft ' 



lyd^ 



231 in.' 



16, 387 cm 

 0,0283 m^ 

 0,7646 m^ 

 3, 7853 liters 



1000 mm^ = 0.06102 in. ^ 



1000 cm^ = 61.02 in. ^ 



1 m^ = 35.314 ft^ 



1 liter = 1. 0567 liquid quarts 



WEIGHT 1 grain = 0.0648 gram 



1 ounce = 23. 3495 grams 

 1 piound = 453. 592 grams 

 1 pound = 0.4536 kilograms 



1 gram 



1 gram 



1 gram 



1 kilogram 



15.4324 grains 

 0.03527 ounce 

 0. 002205 pound 

 2. 2046 pounds 



United States standard kilogram mass is kept 

 at the National Bureau of Standards. 



The standard of mass is kept in a vault. Not 

 more than once a year, the standard is removed 

 from the vault and used for checking the values 

 of smaller standards. The United States stand- 

 ard kilogram mass has been taken to France 

 twice in the last seven years for comparison 

 with the international standard. Every precau- 

 tion is taken to keep the kilogram standard mass 

 in perfect condition, free of nicks, scratches, 

 and corrosion. The standard is always handled 

 with forceps; it is never touched by human 

 hands. 



When the national standard is compared on 

 a precision balance with high precision copies, 

 the copies are found to be accurate to within 

 one part in 100 million. 



Time 



Before 1960, the standard of time was the 

 mean solar second — that is, 1/86,400 of a mean 

 solar day, as determined by successive ap- 

 pearances of the sun overhead, averaged over a 

 year. In 1960, the standard of time was changed 

 to the tropical year 1900, which is the time it 

 took the sun to move from a designated point 



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