Ang Lee hired Steven Callahan as a "nautical consultant." In 1982, Callahan survived 76 days adrift on a rubber lifeboat in the Atlantic after his sailboat sank.
Suraj Sharma was never in the boat with a live tiger. Most of the tiger shots were very high-tech CGI. Only a few scenes, like the tiger swimming in the water, included a real tiger.
Tobey Maguire was originally cast as the Writer. Ang Lee thought Maguire was too famous for such a small role, and would have been distracting.
Suraj Sharma never intended to audition for the film. He went to a casting call to support his brother, and beat out more than 3,000 hopefuls for the lead role.
The shot from overhead of Pi sleeping on the tarp, with Richard curled up in the boat and the fish swimming underneath them, replicates the best known cover of the book that the film is based on.