For clarification, a lot of other people worked on this water too! Perhaps as many as 50 or 60!
Contrary to popular belief, the ship is not CG. It is a miniature, 1/20 scale (about 45 feet long), and easily the most detailed model of the Titanic ever made. It was produced by the Digital Domain model shop, with many outside contractors (1/8 scale and 1/4 scale sections of the ship were also produced for filming in real water). This model survives, and will be on permanent display somewhere, though noone seems to know where as of yet.
The people on the ship, the water, the smoke and steam, the seagulls, and some of the rigging is CG. They are rendered with Pixar's RenderMan. The people were modelled and animated using SoftImage, the other items with Side Effects's Prisms. The sky is a painted photograph, run through "pan and tile" to pan with the scene.
The water is produced using Arete's RenderWorld software, with many modifications that I worked on with them to add reflections and texture mapping to the surface. The "foam" is live action footage shot from straight overhead of the Lane Victory, a WWII victory ship. These images were scaled and duplicated several times to adjust for the fact that the Titanic was three times faster and twice as long, and texture-mapped onto the water surface. The spray against the ship is a Prisms particle system, enhanced sometimes (though not in this shot) with live action shot with high-pressure hoses in a swimming pool.
Though not used in this shot or other "hero" shots, the Titanic was modelled and rendered using LightWave for "set extensions", in particular to make the hull below the full-size set. LightWave was also used to produce a very detailed and accurate "simulation" of the Titanic sinking, unfortunately only a small portion of this simulation is seen in the final cut.
Click here for the Titanic trailer compressed to only 2770 bytes! (joke)
[Countdown to Titanic] click here for links to all Titanic info on the web