Hotshot Navy special ops guys get assigned to take a cruise to keep an eye on a VIP's daughter. Once the voyage is under way, somehow a nuke A) gets lost in the vicinity, and B) goes off. The resulting tidal wave capsizes the cruise ship, and its up to our heroes to save the day.
Intrepid
When a tsunami created by a nuclear explosion capsizes a cruise ship, a special agent must help the surviving passengers reach the surface when it becomes apparent that there's a group of terrorists on board.