James Cameron's obsession with our oceans is perhaps his most dominant personality trait. This is reflected in many of his films, from the earliest days of his disavowed directorial debut "Piranha II," to 1989's deepwater oil drilling drama "The Abyss," more than one ocean documentary, and of course, "Titanic." Maybe even above filmmaking, studying and exploring our oceans is Cameron's most beloved pastime. The filmmaker has completed 12 dives in a submersible vessel to the "Titanic" site...