How does Rainsford end up on the Ship-Trap Island?

Rainsford stays above deck to smoke a pipe. He sits in the silent, dark night and looks out over the water. Suddenly, a sound startles him—the sound of a gun being fired. He quickly walks to the edge of the railing to try to get a better look at his surroundings. He is unable to see anything through the murky darkness. Rainsford accidentally knocks his pipe out of his mouth during his attempts to get a better view. In his attempt to catch it, he loses his balance and falls into the water.

Unable to swim back to the yacht, Rainsford swims in the direction from which he heard the shots. It takes him about ten minutes to swim to shore.