In Golding's Lord of the Flies, two expeditions are described, but neither involves a boat. The first expedition occurs early in the book, and is one of Ralph's first decisions as chief--to explore the island. On this expedition, he takes Jack and Simon. They spot the candle-buds that Simon recognizes, they roll a rock, and discover Castle Rock. The island is untouched by humans. They return from the expedition thinking the island is a friendly one.
The second expedition occurs after Sam and Eric spot what they think is the beast. Ralph, Jack, and initially Simon go on this expedition. Simon, however, goes back to camp to see about Piggy and Roger comes to take his place. In this expedition, the island becomes dark and ominous. Jack passes by a huge rock and still wants to roll it. He thinks Castle Rock would be a great place for a fort. But during this expedition, Ralph and Jack spot the parachute of the dead man. They see it billowing in the wind, and because it is dark and they are already frightened, they believe that this parachute is a beast and run back to tell the others. This event is what eventually divides the boys and causes Jack's rise to power.