In this paper; a submarine vessel’s shell element’s deformation has been investigated due to hydrotatic pressure. Eleven different pressure value for eleven depth has been accounted. A doubly curved shell element within different radius and different lenghts of edges is analysed by using numerical method solution of static linear equilibrium equation of shell element. In the solution part, Navier Solution method with double Fourier series is used for solution of final differantial equations. Identical shell element has been analysed in a package program ANSYSTM in order to verification of solution. Following of verification, cylindrical shell element has been analysed with numerical method. In numerical analysis a MATLABTM code is written for easy solution for different curvature radiuses and different lenghts of edges. After all solution analyses, stres components of shell elements has been compared with Turkis Loyd permitted stress components for design of a submarine. As a result, it’s studied on deformation of isotropic shell element according to different length-thickness ratio and length values.