[manolis a]

hello everybody

i'm interested on keel effect on stability and i have ended up in this formula considering inertia(when the roll radius of gyration is unknown)

I = (m^1.744)/212.2035 (m^2 * kg) by Holtrop

but this probably an empirical only equation

Is it sound to use it on mathematical modelling?
does it takes into account the added inertia due to the added mass?
does anybody know a "safer" approach?

thanxs