Hearts of Oak (1924)

Terry Dunnivan, a retired sea-captain living in Marblehead, Massachusetts, adopts two children, Chrystal and Ned. As the girl grows to womanhood, Terry realizes his fatherly-love had grown to something stronger. He asks her to become his wife. Chrystal, who is in love with her foster-brother, consents rather than destroy Terry's happiness. On the day of their marriage, Ned returns from a long voyage with the intent of making Chrysal his wife. And, he, too, rather than destroy the happiness of his adopted-father, leaves to embark on an Artic voyage that might mean his death. When Terry learns of the sacrifice both Chrystal and Ned are making on behalf of his happiness, he takes Ned's place on the voyage and gets both to pledge that if he does not return, they will marry each other.