A subsea separator vessels includes single machined blocks integrated into a hull so as to combine all the valves used in the process of separating the multiphase fluid in the interior of the blocks. The separator vessels have by-pass valves in their blocks, if necessary to interrupt the separation process. The blocks function as a structure for the separating vessels, thereby replacing all of the metal structure necessary to support the tubes and valves of a conventional manifold, thus reducing the total area occupied by the separation station in the seabed.