The Good Sailor — Jon Adams

Otis starts from Manila on a short cruise that turns into a voyage of weeks and months as he sails farther and farther into the Pacific Ocean. He is somewhere east of Fiji when he passes through the barrier reef of an island he doesn't know the name of because he doesn't have a chart. He has left a lot behind and now he thinks only of sailing home. But the island he has arrived at won't let him leave, not until he finds out what happened on the Far Atoll.