A boat of length 50 m is designed to cruise at 30 mph and is to be tested in a tow tank with a model of length 0.5 m. What is the appropriate model tow velocity in m/s? A boat of length 50 m is designed to cruise at 30 mph and is to be tested in a tow tank with a model of length 0.5 m. If the model wave drag is 1.2 N, what is the estimated full-size boat wave drag in kN?