A20-ft-long model of the containership whose characteristics are given below is towed at the speed corresponding to the design speed of the ship. the tank water is fresh, at 70°f, and the measured model resistance is 14.75 pounds. the ship characteristics are: length-660.0 ft beam 90.7 ft draft 34.5 ft wetted surface 89,300 ft2 displacement 45,140 tons design speed 20 knots