The Goblin sailed on into the fog , but Susan was very unhappy. She was thinking of Jim Brading rowing around in the harbour , looking for his yacht. What would he do when he found that the Goblin had gone? Telephone to Mother at Pit Mill? Jim Brading would have to tell Mother that he didn't know where they were , and that thought really frightened Susan. They had all promised they wouldn't go out of the harbour. And here they were , in someone else's yacht , sailing in a thick fog , faster and faster away from the land. Their promises had been broken. What was better? To break a promise? Or to put their lives , and the Goblin was going on the rocks and shoals?