Sounds a bit like the legend of King Skjöldr, who was a Danish King who came to the shore as a small child in a boat with no other on it on a shild (hence the name.)
Like Moses, too. Bit of a theme going here. Only, she was an adult already; it's curious that she was presumed royalty like the other two. Perhaps she started her journey as a baby, like Skjöldr and Moses, but people just kept putting a little food in and sending her on her way.