They could also make the whirlpool effect by pulsing the fountains on the grid in a circular whirlpool motion around a central point. However, the boats couldn't move too much so that might not work.
Ok, new vision:
Meefog rolls in over the lagoon creating a thick blanket on the surface of the water. Grind nozzles move their streams in a pulsing motion across the lake very wavelike creating a rolling sea and agitating the fog. Swirling and tossing begin in the ocean as green and dark blue light flood the fog and spray reminding any sailer of the terror that is a storm. The back screen pressurizes with a scene of intense rain pooring down over a vast fog shrowded ocean. Lightning flashes through the thick dark clouds which span across the two side screens as well. Then, piercing through the fog like a knife on the right screen is the Black Pearl cannons ablaze to an orchestration of The Medallion Calls. From the veil of a front wall of fountains The Flying Dutchman erupts from underwater onto the left screen engaging the Black Pearl with its own broadside. Bursts of water fly back and forth with blasts of flame from the fire cannons. Debris and cannonballs fly toward the crowd in the form of H2O as the epic battle continues on the high seas. Then from the middle of the water the gaping tentacles (water whips) of the mighty Kraken emerge. A giant eye (a white dome) looks on as the tentacles reach for the of the ships. The Black Pearl fires a broadside and flames erupt from where the Kraken resides underwater. The tentacles retreat (with one whipping down close to the audience). The Dutchman after the loss of it's secret weapon retreats into the waves as the Pearl sails on across the main screen disappearing into a shroud of smoke while the storm continues to roll over the waves.
great idea! I think with this, they could add an angled water screen so it could resemble somewhat of a circle...idk, there's a lot of stuff they could add later to pluss the show. I'd love to see this though. It'd be pretty awesome.