The Titanic Sisters by Patricia Falvey

Sisters Nora and Delia have been given the chance of a lifetime - to escape their poor Irish farm and travel on the Titanic to a new life in America. Delia is to become a treasured governess for a rich family, while Nora has only a lowly maid's position.

But when disaster strikes, and Delia dies, a small misunderstanding leads to Nora taking Delia's place as governess. As Nora grows closer to her charge, and the girl's father, will she be able to reveal the truth to find a chance at happiness? And what will happen when she finds out that Delia is actually alive, and coming to take what is rightfully hers...?