Shipwreck Island (Shipwreck Island, 1, Band 1)

Sarah Robinson is deeply troubled in the wake of her dad's second marriage. She now has to deal with a new stepmom and two stepbrothers, Marco, who is her age, and Nacho, who's younger. Even though they've all moved from Texas to California to start life as a new, blended family, none of the kids seem remotely happy about it.

Sarah's dad and stepmom then decide to take the whole family on a special vacation in order to break the ice and have everyone get to know one another. They'll fly to Tahiti, charter a boat, and go sailing for a few days. It'll be an adventure, right?

Wrong. Dead wrong.
Shipwreck Island is the first installment in a series from S. A. Bodeen.