Along the rocky coast just a little southeast of the Sandycove tower lie several rocky landmarks that play minor roles in Ulysses: “the Muglins," "Bullock harbour," and "Maiden's rock."
Dalkey Island, not mentioned in the novel, is the largest of several rocky outcroppings off the point where the coastline changes its southeasterly course and drops due south. This island is no longer inhabited but contains the remains of some sparse settlements. The rocky shoals east of Dalkey Island, called the Muglins, pose a significant hazard to shipping, and so have been fitted with a light. As Mulligan, Stephen, and Haines approach the fortyfoot hole in Telemachus, they see "a sail tacking by the Muglins."
A little later in the same episode, Stephen and Haines approach two men who are observing the sailboat's course: "— She's making for Bullock harbour." Bullock Harbour is a small artificial harbor, constructed from local granite, that lies close to the tower, less than half a mile away. This harbor cannot accommodate large ships, so the sailing vessel must be of very modest size.
Much later, in Oxen of the Sun, the narrative observes that Theodore Purefoy likes to fish from a boat off the small harbor: "Her hub fifty odd and a methodist but takes the sacrament and is to be seen any fair sabbath with a pair of his boys off Bullock harbour dapping on the sound with a heavybraked reel or in a punt he has trailing for flounder and pollock and catches a fine bag, I hear."
The two anonymous men who comment on the boat's course in Telemachus also remark on a man who has drowned in in the ocean nine days ago: "The boatman nodded towards the north of the bay with some disdain. / — There's five fathoms out there, he said. It'll be swept up that way when the tide comes in about one. It's nine days today." Stephen makes the assumption that the sailboat is conducting a search for the body: "The man that was drowned. A sail veering about the blank bay waiting for a swollen bundle to bob up, roll over to the sun a puffy face, saltwhite. Here I am."
In Proteus, he thinks again about the corpse surfacing, and names the place where he drowned: "The man that was drowned nine days ago off Maiden's rock. They are waiting for him now." Maiden Rock lies just north of Dalkey Island, so the boatman is assuming that the tide will have swept the body far to the north.