A Deadly Silver Sea — Bob Morris

The world's most exclusive cruise ship, the Royal Star, has just set sail from Miami on its inaugural voyage. For the hundred or so well-heeled passengers, including Zack Chasteen and his wife, the itinerary is a secret, and the week ahead promises to be the ultimate tropical sojourn...

But just an hour out of port, gunmen take over the Royal Star, killing most of the officers and sequestering passengers throughout the ship. Not only is Zack separated from his wife, he has another worry: she is eight months pregnant, and could go into labor at any moment

As Zack and his fellow captives struggle to gain the upper hand, the hijackers offer few clues to their motives. Maybe it's a simple kidnap/extortion plot. Or maybe they're bent on more devious ends -- using the Royal Star as a giant torpedo to blow up another cruise ship. Either way, Zack must figure out a way to stop them -- while keeping himself, and his family, alive.