Estimation of the Hydrodynamic Derivatives in Deep and Shallow Water

The Hydrodynamic derivatives are divided into two main groups, one is linear and the other is non-linear. The captive model test data of a very large number of ships have been collated. The data represents a large number of ship types with different loading conditions and different ship particulars and cover a period of more than 25 years. These data formed the BMT manoeuvring database.

The multiple regression analysis was used to develop mathematical expressions References23] for the linear and non-linear terms of the mathematical model. The low aspect ratio wing theory is used to find out the main parameters which will be used in the regression analysis. Equations <blue> to <blue> give the main parameters of each derivative.

The shallow water effect on each derivative was studied on the basis of the available experimental data. It was found that the shallow water effect is almost proportional to ; where T is the ship draught and H is the water depth. Each hydrodynamic derivative has a shallow water correction factor in the form: