Thousand Shades of Blue — Robin Stevenson

A sailing trip to the Caribbean might sound great, but sixteen-year-old Rachel can't stand being trapped on a small boat with her family. She misses her best friend and feels guilty about leaving her older sister Emma, who lives in a group home. Her father is driving her crazy with his schedules and rules, her brother is miserable, and there is never anyone her own age around. Worst of all, there is nowhere to go when her parents fight. While their boat is being repaired, the family spends a few weeks in a small Bahamian community, where Rachel and Tim discover a secret which turns their world upside down and threatens to destroy the fragile ties that hold their family together.