When did Karana decide to leave the island and why

During the storm, Karana decides that she should repair a canoe and sail to nearby Santa Catalina. She takes the tribe’s smallest canoe, which still holds some dried food from the previous year. Meant to carry six people, it is too big for Karana to handle easily, but she is determined to escape the island. She paddles all day and into the night, using the North Star to guide her.

Unfortunately, the canoe starts to leak. Karana tries to plug the leak with a piece of her dress, to little avail. Eventually, she accepts that she will never succeed, and turns back with a heavy heart. The only thing that cheers her up is a group of blue dolphins who swim with her as she journeys back to the island. They give her hope and strength to keep rowing, and she lands back on the island shore within a day.