Read the following article and answer the question.

She remained with them until she was four years old , when a run in with an enemy ship caused her parents to bring her ashore to live with her paternal grandparents in Australia . When she was seven , her parents returned and brought her to Long Beach to live with her maternal grandparents . Though they were far apart , her parents were faithful to visit each month and take her on long trips during the summer .

Why did they have to stay with their grandparents ?
Their parents were traveling .