This International Standard specifies the procedure to be applied in analysing the results of speed trials for ships, with reference to the effects which may have an influence upon the speed-power-revolutions relationship. The applicability of this International Standard is limited to commercial ships of the displacement type. The instrumentation to be used in the speed trials is not specifically indicated, nor is the method of conducting the trials. Calibrated instruments and their methods of use commonly adopted for such trials should be acceptable. In this International Standard, it was decided that the unit to express the amount of an angle should be “rad” (radian) and that the unit of speed should be “m/s” (metres per second). Nevertheless, “°” (degree) as a unit for an angle and “kn” (knot) as a unit for speed may be used. However, the units for the angles and speeds which appear in calculation formulas are to be “rad” and “m/s” without exception. Moreover, for the convenience of the users of this standard, numerical values using the units of degree and knot are stated jointly at appropriate places.