A government survey of a remote, uninhabited Pacific atoll in 1985 finds no trace of a missing boat or any human burial. Three years later, in 1988, scientists discover both a wrecked boat and a carefully constructed grave on the same atoll. The boat had been missing since 1979. Ocean current models suggest the boat could have drifted to the atoll within three months of its disappearance. How can all three facts — the boat could have arrived by 1979, the 1985 survey found nothing, and the 1988 expedition found both boat and grave — be simultaneously true? Propose the most parsimonious explanation that accounts for the timeline without invoking supernatural causes.