Abstract: The article presents the results of calculations of the pressure fields generated by a motorboat at the bottom of a shallow sea. Calculations were made using the boundary elements method (BEM), arranged on the surface of the boat and the bottom of the sea. This method is described in [3], and applied on a free surface linearized boundary condition. Results for four different lengths of motorboats, from 2.85 m to 9.5 m, sea depth from 1 m to 10 m, are presented in the form of a surface, approximated by a polynomial function whose coefficients are given. These functional relations allow one to calculate the maximum and minimum hydrodynamic pressure generated by the motor boat length, in the range as above, and the sea depth to about 10 m when flying at speeds of up to 20 m / s. Given functional dependencies can be used, in the field of security and anti-terrorism defences, and can serve to identify the type and size of speedboats, up to about 10 meters and a displacement of about 8 tons.