The video shows how the commercial finite element computer package, namely ANSYS, can be used for determining the nonlinear collapse pressure of a submarine pressure hull, under external hydrostatic pressure, The analysis considers both material and geometrical nonlinearity. For more details of this procedure, the viewers are advised to consider reading: [1] Finite Element Techniques in Structural Mechanics. [2] Advanced Applied Finite Element Methods. [3] Pressure Vessels:External Pressure Technology. All published by Woodhead Publishers, Cambridge, UK, and written by Carl T.F. Ross.