He had his companion Wilson the volleyball who he would talk to throughout the film, solving the problem of Hank’s character needing to talk, without actually having anyone to talk to.
This idea for a volleyball companion came about when screenwriter William Broyles, Jr. was researching for the film. He consulted with professional survival experts, and then chose to deliberately strand himself for one week on an isolated beach in the Sea of Cortez, to force himself to search for water and food, and obtain his own shelter.
While he was stranded on this island, a volleyball washed up on shore, giving him the inspiration he needed for Wilson the volleyball companion.
The company Wilson Sporting Goods did not pay for the product placement, but they certainly took advantage of the free publicity. They launched their own joint promotion centered around the fact that one of its products was "co-starring" with Tom Hanks!
