Problem with Hydromax (MAXSURF)

[Sarinha]

I am currently designing an underwater nozzle (with a hydrodynamic profile, such as a NACA). inside the nozzle (ring) is not massive (it will be built with two steel shells: an outer and inner surfaces have defined as separate in the program)

I want to use the inside of the ring for ballast, so I want to define it as a tank in Hydromax, but I have not got the program correctly understands the limits of the hull, the outer surface yes, but not the inner hull and what is is a cylindrical tank with the outside diameter of the nozzle (not a ring). Both the exterior and interior surfaces are defined as Hull.

Can you help me?, Please!

[cokepe]

you have to define the inner surface has structure and in the compartment definition window, in the boundary surfaces column you have to click the cell and a window showing the surfaces defined has structure, note that there are two surfaces with the same name but one with the (P) it means that you can select the Starboard side or the port side of the surface or both.

[Sarinha]

Thank you very much for your help, copeke!!! But I still have the same problem...
I just realized that I have the same problem in Maxsurf, I calculate the hydrostatics and the volume that it is for a cylinder of radius equal to the outer radius of the nozzle, not the annular space!!!!!!!!
Does anyone know where I can be making the mistake?