Gerr's Roll Period Recommendation

Regardless of the lack or presense of degrees it's even more complicated than you describe it Alik. Howabout dynamic effects under way which change the amount of these additional damping and roll motion forces further. Or lying-a-hull when wave patterns have same amplitude with the vessel the appendages or their absense doesn't have a great difference. So whatever you calculate with this approarch you never get any excact outcome becouse it varies with conditions. So IMHO if we talk about roll period it best to leave at it's simplest form thou it's good to know other things may change it..
BR Teddy