Hunter x Hunter - episode 20 - 10 Mar, 2000

The group works together to separate the battleship/hotel from the island before the second wave of the storm hits. Leorio gets stuck on the bottom of the ocean in a diving suit and Gon helps him escape. Gon is then saved by Hisoka. Kurapika is knocked out but the steering is done by a mysterious examinee who seems to be Hisoka's ally. They separate the ship just in time, and a blimp comes to pick them up. (Source: Wikipedia) Hunter Exam arc: (20/31)