Keel Hauling

Keel Hauling is an individual physical water-based challenge that originated in, and was reused in.

Rules
The contestants are divided into heats. In the first round, contestants race across a pontoon and dive into the water. Using a rope suspended beneath the platform, they pull themselves, underwater, to the other end. Upon climbing back onto the platform, they move a ring from one end of the pontoon to the other. The first contestants from each heat to move two rings move onto the final round, where five laps are undertaken. The first castaway to move all five rings wins the challenge.

History
The challenge debuted in as the first individual immunity challenge after the merge. Burton Roberts, newly returned to the game following the Outcasts twist, won the challenge and immunity. As the Outcasts twist gave him immunity at his first tribal council upon returning to the game, he gave immunity to Rupert Boneham.

The challenge did not appear again until. Notably, Phillip Sheppard elected not to compete in the challenge, becoming the first contestant to forfeit an immunity challenge without an added incentive. Andrea Boehlke, Brenda Lowe, Malcolm Freberg and Reynold Toepfer made the final heat, where Reynold ultimately winning immunity.

Trivia

 * This challenge has only been used at the Final Ten.
 * Only men have won this challenge.