Division 1.3: ‘Froude number’ Fn shall be calculated by dividing the maximum recreational craft speed V (m/s) by the square root of the waterline length lwl (m) multiplied by a given gravitational acceleration constant, g, of 9,8 m/s2. - Directive 2013/53/EU of the European Parliament and of the Council of 20 November 2013 on recreational craft and personal watercraft and repealing Directive 94/25/EC (Text with EEA relevance)

F_{n} = \frac{V}{\sqrt{(g. lwl)}}

‘Power to Displacement ratio’ shall be calculated by dividing the rated engine power P_N (in kW) by the recreational craft’s displacement D (in tonnes)

Power to Displacement ratio = \frac{P_{N}}{D}

Division 1.3 ‘Froude number’ Fn shall be calculated by dividing the maximum recreational craft speed V (m/s) by the square root of the waterline length lwl (m) multiplied by a given gravitational acceleration constant, g, of 9,8 m/s2.