Abstract
The Author proposes in this paper the obtaining of the mathematical model for a surface which is a good aproximation for the bonnet, and this modeling is based on the surface parameters.
In mathematicals model building is neglected the yowing velocity and is only considerated the rolling and pitching velocity.
Finally, the transversal points desplacement which belonging to the medium plane of the surface is obtained, and this relation is particular expressed for the harmonics vibrations of the bonnet.