If you look closely at the design of the boat in Frozen then imagine it as a shipwreck you would probably think that the boat would look like the ship in the Little Mermaid. Now at the end of Tangled Flynn (Eugene) and Rapunzel have a wedding and Tangled was released about three years before Frozen and the king and queen "die" three-ish years before the main event s in the story. So its highly likely that the king and queen were on the way to the royal wedding. But what makes this even more reassuring is that Flynn (Eugene) and Rapunzel were at Elsa's coronation. Mind blowing. If Elsa and Anna' parents died on the way o your wedding wouldn't you feel obliged to attend the coronation of the future queen of Arendale. Wouldn't you think.