Mission To Cuba by Jim Watt

Jack Hughes is a 16 year old orphan. His only inheritance is a 30 foot sailboat and he intends to sail it down the Intra Coastal Waterway from Baltimore to Miami in memory of his recently killed parents who loved to sail. He is joined by a 16 year old girl who has run away from home and wants to forget her home life. They rescue a young boy in Chesapeake Bay and are led to searching for the boy's parents' killers all the way to Cuba.