Havana Storm by Clive Cussler

While investigating a toxic outbreak in the Caribbean Sea that may ultimately threaten the United States, Pitt unwittingly becomes involved in something even more dangerous—a post-Castro power struggle for the control of Cuba. Meanwhile, Pitt’s children, marine engineer Dirk and oceanographer Summer, are on an investigation of their own, chasing an Aztec stone that may reveal the whereabouts of a vast historical Aztec treasure. The problem is, that stone was believed to have been destroyed on the battleship Maine in Havana Harbor in 1898, which brings them both to Cuba as well—and squarely into harm’s way. The three of them have been in desperate situations before . . . but perhaps never quite as dire as the one facing them now.

The Spy by Clive Cussler

Set in 1908, bestseller Cussler and Scott's action-packed third adventure featuring Isaac Bell, head operative of the Van Dorn Detective Agency, leaves behind the railroad theme of the first two books (The Chase and The Wrecker), focusing instead on the espionage-riddled world of warship and armament manufacturing in the buildup to WWI. Someone is murdering the leading lights of America's naval research and development. When the indefatigable Bell looks into the supposed suicide of chief gun designer Arthur Langner, he uncovers a succession of possible international suspects, all of whom are attempting to disrupt America's development of a fleet of dreadnought battleships. Bell clashes with old enemies and new until the climactic battle, where he must stop a massive submarine attempting to sink the navy's newest battleship.