Gilbert Morris 
Voyage of the Dolphin [EPUB ebook] 

How lucky can they get? It’s relaxation time, and the Seven Sleepers are vacationing on an ocean-going ship. How much trouble can they get into on vacation- none, right? Almost before they can sort out what’s happening, Josh, Sarah, and their friends find themselves entangled with: a handsome sea captain who can’t find a crew, a maddening rich girl who wants to be queen, a band of friendly and unfriendly giants, and the biggest hurricane of the century. But where is their powerful friend God? Does He know where they are? Does He even care? Sail along with Josh and the crew as they handle danger and fear, and see if you can figure out why God doesn’t just rush to their rescue.