Now, let us see how are things extrapolated? Speed of model, Vm, gives Vs equal to Vm into root lambda, Froude similarity; Froude number, Vm by root glm equal to Froude number ship- Froude number is same; density, density of water, now, this is fresh water for model, rho model is fresh water at temperature measured, and ship, sea water, and for all calculations we take 15 degree centigrade as standard temperature, 15 degree centigrade and this sea water density at 15 degree centigrade is 1025.9 kilograms per meter cube, at same temperature rho m is 999 kilograms per meter cube. So, you see there is an increase in density.