 After Jason helps Kimberly escape the bilge of Divatoxs craft, she  was actually supposed to lose consciousness from lack of air and  sink into the ocean. After Mandika the mermaid, a character that was  supposed to be used in the film, saves Bulk and Skull by giving them  a log to use so they can swim to Muranthias, Mandika saves Kimberly  from drowning and takes her to shore. While the sequence and all  footage of Mandika were cut, the epilogue of the scene remains when  it shows an exhausted Kimberly on the beach and she is found by the  native tribal warriors on the shore. This explains why Bulk and  Skull arent as tired as Kimberly when she arrives on the island.