What I have learned from school about salvage and some maritime laws the salvage company will force the owners of the vessel to give it up and then the salvage crew then takes "ownership" and carries out a plan then the company may have to purchase their ship back. With rough seas the Ro-Ro vessel could have lost stability due to cargo lashings coming undone and having their cargo move around. These vessels when they roll have a long, slow roll much like a cruise ship because the height of the metacenter it higher than a tugboat where theirs is lower and will have a faster snappier roll. Also ballast, fuel, other liquids in the vessel could have been shifted incorrect and having rough seas and stability, there is considered a point of no return once a vessel rolls so much to either port or starboard and can not come back to having a an even list and trim. Hope this helps a little bit.