The paper was developed in the frame of a cooperation between University of Trieste and Fincantieri Shipyard on the possible revision of IMO Weather Criterion for ships having the characteristics identified in the title, like the modern cruise passenger vessels. Previous studies on the development of Weather Criterion identified the weak-points which to large extent lie in the overestimate of rollback angle due to several factors. These factors concern both the metocean conditions and the roll motion modelling. This last factor was explicitly addressed and a thorough research plan was prepared concerning the nonlinear roll motion modelling and a campaign of tests on scale models aimed to identify appropriate ranges of roll damping and effective wave slope coefficients. Tests in beam wind to update the drag coefficients for large windage area ships will also be done. The general idea, the experimental difficulties and the data analysis procedures are presented in the paper.
