Would be very helpfull to have the possibility to import at lest solid geometry (thin) in STP and also STL file.
The work process could be: design the hull geometry with Freeship, inport the IGS or STP file in a different CAD (Pro/E or CATIA), refine the geometry, inport again the refined geometry in Freeship to analize it.

Anyway it's a realy wanderfull SW.