It is not a castle remnant or a folly, but a navigation beacon, one of three that once worked in concert to guide vessels safely into the harbour. That trio arrangement is what sets this site apart: a second beacon sits approximately 100 metres to the south-southwest, and a third occupies Gun Island on the far side of the harbour, roughly 440 metres away. Together, they would have given mariners a set of fixed reference points, each visible from the water at different angles, covering a panoramic arc from east-northeast to west-northwest.

The tower itself is modest in scale, around 3.4 metres in diameter, and built from roughly coursed masonry, the kind of practical stonework that prioritises function over finish. The exterior is rendered and whitewashed, which would have maximised its visibility against the dark hillside. Towards the top, the structure tapers slightly before reaching a projecting cornice, above which two stepped bands of ashlar masonry, that is, finely cut and dressed stone, form a cap. The contrast between the rough lower courses and the more precise ashlar finish at the crown suggests a builder who understood that the upper portion, most visible from the sea, deserved the cleaner work.