After completing the arduous task of salvaging supplies from the ship, the narrator recognizes the immediate need for a more "permanent shelter." The primary motivation is the fear of "wild animals or natives," necessitating a secure environment. After careful contemplation on the beach, the narrator decides that a singular solution is insufficient; instead, a combination of a "cave for storage" and a "better tent" is required. Seeking an optimal location that is neither too hot nor too far from "drinking water," while remaining visible enough to "watch for passing ships," the narrator and their dog, Shippy, embark on an island-wide survey. They eventually discover a "nice grassy plain on the side of a rising hill," which serves as the perfect foundation for their new camp.
Moving all supplies to the new location takes "several days," during which Shippy acts as a guardian. The construction process is deliberate and defensive. The narrator builds a "fort" by planting "young trees from the forest" around a small cave, reinforcing these with walls. Prioritizing safety, the narrator constructs a "ladder" instead of a door to gain entry, ensuring the perimeter remains secure. To accommodate Shippy, a hidden entrance camouflaged with "palm leaves" is created. This structure provides the narrator with "great protection and peace of mind," allowing them to organize their resources effectively, such as separating "gunpowder" to protect it from lightning and ensuring food supplies remain preserved.
With the "basics covered"—food, water, and shelter—the narrator begins to reflect on their newfound capabilities, noting, "Who knew that I had the strength and will to survive?" The daily routine involves hunting "wild goats," which become a "central part of my diet." However, physical survival does not alleviate the profound psychological toll of isolation. The narrator experiences moments of deep melancholy, often "sitting and crying" while thinking of family and lost fellow sailors. To cope with this solitude, the narrator utilizes "paper and ink" salvaged from the ship to keep a "diary," which serves as an essential emotional outlet during times when their "heart ached."
As the end of October approaches, the narrator focuses on maintaining a sense of temporal order. Having been away from Brazil for two months, the narrator establishes a systematic way to track time. They utilize a "calendar on a big tree," marking each day with a straight line and crossing them out weekly. By calculating the timeline from their departure on September 1st and the subsequent 30 days at sea, the narrator designates September 30th—the day they landed on the island—as their "anniversary." Establishing this structure, differentiating "Friday from Sunday" and "Monday from Wednesday," provides the narrator with a vital sense of normalcy and "set my mind at rest" amidst the challenges of their solitary existence.