What Is A Deck Prism On Ships?

A Deck Prism was fitted into a ship’s deck to illuminate the areas where sunlight could not penetrate. For centuries, sailing vessels used the reflection and refraction from deck prisms to provide light on board wooden ships. Though candles and kerosene lamps were also used, these posed a hazard.

Meanwhile, the glass prism dispersed the natural sunlight into the space below from a small deck opening without compromising the vessel’s seaworthiness.

Usually, it hung below the overhead and dispersed light in a sideward fashion. The top was flat and had a flush with