What was David's four days on the rocks like in Kidnapped by Robert Louis Stevenson?

David Balfour was stranded for four days on the tidal islet of Earraid. In the end, his clothes were in rags and tatters, his stockings worn through so that his "shanks were bare" and his throat continually soar and swollen. He struggled ashore on the islet in the cold dark of mid night and wander along the fearful deserted seaside. After climbing a treacherous hill, he saw the ship was nowhere in sight and most likely sunken. Aching with hunger and shivering with cold and marveling that not a sound but the sea could be heard, he began walking to find human habitation. What he found instead was an impassable creek that he thought he might ford of float across using the yard that had saved him from the sea, but the yard was twenty feet beyond his ability to retrieve it. He discovered next that he was isolated on a small isle to which none ventured.

David's meals were of raw, cold sea limpets and shell buckies that alternately made him violently and dangerously ill or gave him sustenance. He took shelter in the crags of the rocks for the one small pig's hut had a collapsed roof. He favored a spot where he could see the church spire and the smoke of chimneys from the not-too-distant Ross of Mull, his only comfort during the four days of his marooned exile. On the third day two fishermen in a passing boat laughed at David's cries of supplication that they stop and rescue him for which he threw himself into a violent rage of fierce anger, but the next day they returned and gesticulated to Gaelic words that he could get across when the tide was out. He could escape the torture of his tidal prison twice in twenty-four hours when the tide was low.