A fire broke out on the 136 meter long, 3676 dwt ro-ro ferry Stena Nautica on the Kattegat between Grenaa and Varberg, Sweden.  The fire started in one of the trucks on a cargo deck.    The crew responded and quickly brought the fire under control.  A small amount of smoke was spotted in the upper decks, but there was no damage to the vessel.  The Stena Nautica arrived at Varberg where it safely unloaded its passengers and vehicles.  No reports of injuries to the 77 passengers and 40 crew on board.  The police launched an investigation into the incident.