The next day when it is time for the father and Fritz to leave for their trip back to the shipwreck, the father calls out for Ernest and Jack so that he can leave instructions for their day. However, the younger sons are nowhere to be found. The father must leave, but before he does, he tells his wife to discipline the boys upon their return. They know that they must not leave the area around the house without first informing their parents.

As the father and Fritz near the Jackal River, they are pounced upon by Ernest and Jack, who have been waiting for their arrival. The younger boys thought this would be a good joke on their father and oldest brother. The younger brothers also had hoped that by stealing away and waiting for them at the bridge, their father would let them come along on the trip to the ship. Though the father is slightly amused by the young boys' tactics, he cannot reward them for disobeying the rule of asking permission before they leave the family compound. He sends the boys home.

While on the ship, the father and Fritz build a new raft. This time they use full-sized, capped barrels as floating devices. They lay the barrels on their sides and tie them together and then build a platform on top. This creates more area for carrying supplies.

After searching through the ship once again, they discover many new items, including a chest filled with gold coins and another with jewelry. Though they are tempted to take these chests with them, they soon realize that on the island the gold and jewelry hold no value for them. Instead they load the raft with more food, cooking utensils, gardening tools, and an assortment of fruit trees. Since the ship had been packed with implements suitable for starting a new colony, the items they discover suit them remarkably well, given they must set up a homestead on the island.

When Fritz finds harpoons, his father allows him to load them onto the raft, though he has no idea how they will ever use the whaling tools. Fritz lets the harpoons hang in the water as they make their way to shore. About halfway back, Fritz notices something big floating in the water nearby. Upon examining the creature, the father identifies it as a large sea turtle asleep on the water. They steer the raft closer to have a better look. The raft's sail is between the father and son, so the father cannot see what Fritz is doing as they come upon the sleeping turtle. However, suddenly the raft feels self-propelled, going at tremendous speed. The raft is traveling so fast the father fears it will capsize. Then Fritz yells out that he has hooked the huge turtle with a harpoon.

With a little luck and the father's strenuous steering, they make their way back to shore on the raft. By this time the turtle is exhausted, and the father puts the creature out of its misery. The family soon will feast on turtle stew.