Principles of naval engineering - Historic Naval Ships Association

PRINCIPLES OF NAVAL ENGINEERINGTable 7-3 gives some selected values formechanical units in British systems of measurement.Table 7-4 gives some selected valuesfor mechanical units in metric systems ofmeasurement. Table 7-5 gives some Britishmetricand metric-British equivalents. The examplesgiven in these tables are chosen primarilyto help you develop an understanding ofthe relative sizes of the mechanical units. Morecomplete tables are available in many physicsand engineering textbooks and handbooks.STANDARDS OF MEASUREMENTThe importance of having precise and uniformstandards of measurement is recognized by allthe major countries of the world, and internationalconferences on weights and measuresare held from time to time. The InternationalBureau of Weights and Measures is in France,Each major country has its own bureauor officecharged with the responsibility of maintainingthe required measurement standards, includingthe basic standards of length, mass, and time.In the United States, the National Bureau ofStandards (NBS) is responsible for maintainingbasic standards and for prescribing precisemeasuring techniques.LengthUntil quite recently, the international standardof length was a platinum- iridium alloy barkept at the International Bureau of Weights andMeasures in France. By definition, the standardmeter was the distance between two parallellines marked on this bar, measured at 0°C.Copies of this international standard were maintainedby other countries; the United StatesTable 7-3. —Selected Values of Mechanical Unitsin British Systems of Measurement.TYPE OF MECHANICAL UNIT