A friend worked on this...

His name was Brian Westfall, but he unfortunately died in an auto accident in July 2004 at age 28. He was hired right out of USC film school to assist James Cameron's brother Mike (company Dark Matter LLC) in helping document behind-the-scenes footage aboard the Russian ship Keldysh, when they went out to the Titanic for this movie. They shipped out from Newfoundland. Being a movie geek and huge fan of the movie 'Titanic', this was very exciting for him.
Anyways, Brian said that James was tireless and energetic in helping to load and unload equipment onto the ship, up and down the steps, and gave a hard time to those who were younger than him who were slow in doing so.
Also he said that Bill Paxton was cool and excited to be there, saying, "George Lucas can make his cartoony special effects all he wants...but we're going out to the Titanic, baby!"
For some reason Brian never received a final credit on the film.