Manned Submersible Ictineu 3: Design and Construction of the Pressure Hull

This paper describes the design and construction of the pressure hull of Ictineu 3, a manned submersible with a maximum operative depth of 1200m. The pressure hull is composed of two stainless steel spheres of 1700mm and 800mm of internal diameter. The material was specifically selected for its excellent mechanical properties and its high corrosion resistance. The main sphere is equipped with a large acrylic spherical sector window that provides the crew with an exceptionally wide field of view. The pressure hull, designed under the ASME PVHO-1-2007 and Germanischer Lloyd rules, will be tested in an autoclave at a test pressure corresponding to 1440m. Finite Element Method (FEM) simulations were performed. The design and manufacturing process is a cumbersome engineering challenge because of the extreme pressure conditions and extremely low tolerances required by the certification agency.