THE DECK PRISM STORY
From a 19th-century deck to your home.
How a clever piece of maritime lighting became a hand-cast glass heirloom.
01
What is a deck prism?
A
deck prism is a solid piece of cast glass, shaped as a 6-sided pyramid. In the days before electricity, light below a vessel's deck was limited to candles, oil, and kerosene lamps.
A clever solution to this light problem was the deck prism. Laid flush into the upper deck, the 6-sided prism pointing down dispersed the light to the cabin below.
02 · WHY SHIPS USED THEM
Daylight, without the danger of flame.
On the top deck of the ship, deck prisms allowed sunlight during the day to be dispersed to the cabin below as a source of light, in addition to candlelight.
Open flame on a wooden vessel was dangerous. The deck prism brought natural light below deck safely — a small piece of glass doing the work of a window where none could exist.
03
The Charles W. Morgan connection
These are genuine replica deck prisms from the Charles W. Morgan sailing vessel, which is berthed at Mystic Seaport, CT.
The Charles W. Morgan is the last wooden whaleship of the American fleet. These prisms are faithful reproductions of Mystic Seaport's last remaining original Charles W. Morgan deck prism.
04
The restoration discovery
During a major restoration (1977–1984), it was discovered that several of the original deck prisms on the deck of the ship had been cracked and damaged.
05
How the replicas were produced
Molds were taken from the original 19th-century deck prisms, and hand-cast replicas were produced to replace the original ones.
06
Hand-cast in the United States
These deck prisms are still hand-cast here in the United States. All of them come in decorative gift packaging. Sometimes, pouring the liquid glass into the mold, small bubbles or small specks may appear — normal, and the same method used in the 1800s.
07
From maritime history to home decor
19TH CENTURY
Deck prisms at sea
Before electricity, deck prisms laid flush into a ship's upper deck dispersed daylight down into the cabins below — a safe alternative to open flame on wooden vessels.
1977–1984
The restoration
During a major restoration of the Charles W. Morgan at Mystic Seaport, several of the original deck prisms on the ship's deck were found cracked and damaged.
FROM THE ORIGINALS
Molds taken
Molds were taken from the original 19th-century deck prisms, and hand-cast replicas were produced to replace them.
TODAY
Still hand-cast in the USA
Those same prisms are still hand-cast here in the United States, each presented in decorative gift packaging.
AS SEEN ON BIG SCREEN
Our deck prisms Went to Hollywood
Warner Bros. Studios in England purchased our large deck prisms for two ships built for the films In the Heart of the Sea and Pan.
If you watch these movies, keep an eye on the deck as the actors walk across it, and you'll catch a glimpse of a deck prism embedded in the deck floor.
