Answer
Dynamic stability is the work done in heeling a ship from upright to a given angle against the righting moment. It is equal to displacement multiplied by the area under the GZ curve up to that angle. It is measured from the curve of statical stability by calculating the area under the curve using Simpson’s rule, trapezoidal rule, or planimeter. Its unit is tonne-metre-radian or kN-m-radian. It represents the energy absorbed by the ship before reaching that angle of heel.