Kraken — Eric S. Brown

Desron 22 was on standard, shakedown maneuvers when the squadron discovered the Pleasure Bound. The massive cruise liner was adrift, everyone aboard her, dead except for a single survivor. The man's wild tales of monsters from the deep were hard to believe until those very monsters came after the squadron itself. Now a desperate battle for survival rages on the waves as the firepower of the United States Navy goes head to head with unspeakable terrors no human was ever meant to see and live.