John Day (carpenter)

Lore & Background

John Day was an English carpenter and wheelwright who built a wooden 'diving chamber' without an engine. With financial support from gambler Christopher Blake, Day attached his invention to the deck of a 50-ton sloop named the Maria, which Blake had purchased for £340. The sloop's hold contained 10 tons of ballast, and two 10-ton weights were attached beneath the keel that could be released from inside the diving chamber. An additional 20 tons of ballast would be loaded after Day was locked inside.

Day claimed he had previously spent 6 hours underwater in East Anglia in a different vessel. He bet Blake that he and his boat could descend to 130 feet and stay underwater for 12 hours. Blake lost initial bets on the venture due to construction delays that prevented the dive within a specified 3-month period.

On 22 June 1774, the Maria was towed north of Drake's Island in Plymouth Sound. Day took a candle, water and biscuits on board, and the boat was equipped with a hammock. After the boat was locked, the weights were loaded and the boat sank forever. Day had the calculation of the trim completely wrong. It has been speculated that Day may have died from asphyxiation, hypothermia or catastrophic structural failure due to water pressure.

Reader's Guide

John Day's death marks the first recorded fatal accident involving a submarine, highlighting the dangers of early underwater experimentation. His venture, backed by gambler Christopher Blake, illustrates the speculative and often reckless nature of 18th-century technological innovation. The failure of Day's calculations—particularly regarding trim—underscores the lack of understanding of buoyancy and pressure at depth. Nikolai Detlef Falck's rescue attempt a month later, based on a belief in suspended animation, and his subsequent pamphlet, reflect the mix of scientific curiosity and superstition surrounding early submersibles. Day's story serves as a cautionary tale in the history of submarines, emphasizing the risks taken by pioneers who lacked modern engineering knowledge.

Did You Know?

• John Day is the first recorded person to die in a submarine accident.
• Day's diving chamber was made of wood and had no engine.
• The sloop Maria carried 10 tons of ballast in its hold and two 10-ton weights beneath the keel.
• Nikolai Detlef Falck attempted a rescue a month after Day's descent, believing Day might be alive in suspended animation.

Trade and Craft

John Day was an Englishman born around 1740 who worked as both a carpenter and a wheelwright. These were hands-on trades rooted in woodworking and mechanical construction. As a carpenter, he would have shaped and joined timber for structural and functional purposes. As a wheelwright, he specialized in building and repairing wooden wheels—a critical craft in an era before rubber tires and metal rims dominated. By the mid-eighteenth century, these skills represented the kind of practical mechanical knowledge that ordinary tradespeople possessed, knowledge that could be extended into more ambitious engineering projects. Day's dual training in carpentry and wheelwrighting gave him a working understanding of wood, joints, load-bearing structures, and rotating mechanisms. This combination of skills would later prove relevant when he turned his attention to a far more ambitious and dangerous project: an experimental diving chamber. His life spanned roughly from 1740 to 1774, placing him firmly in the Georgian era of English history.

The Diving Chamber

Among the various projects a skilled tradesman of Day's era might undertake, his most notable was an experimental diving chamber. This was a maritime device designed to allow a person to work or travel beneath the water's surface. The fact that it was described as experimental suggests it was a prototype or proof-of-concept rather than a finished, proven product. As a carpenter and wheelwright, Day would have drawn on his practical knowledge of construction, joints, and structural integrity in building the device. The chamber represented a significant leap from the everyday objects of his trade into the realm of engineering and exploration. It was a device meant to conquer one of humanity's oldest barriers: the underwater environment. Yet it remained in the testing phase, never having been proven safe or fully reliable in its final form. For a man whose daily work involved shaping materials and assembling functional objects, the diving chamber was the ultimate test of his craft—pushing his skills into a domain where failure meant not a broken wheel but a lost life.

The Fatal Test

John Day's life ended in 1774 during a test of his own experimental diving chamber. He was present when the device was put through its paces, and the test proved fatal. The specific circumstances of his death—whether the chamber failed structurally, flooded, or succumbed to the pressure of the sea—are not detailed in the available historical record. What is clear is that the man who built the device was there when it claimed his life. This places Day squarely in a long and somber tradition of inventors who perished while demonstrating or testing their own creations. He was not a passenger in someone else's machine; he was the maker, the designer, the one who had conceived and assembled the device. His death at the hands of his own work underscores the inherent risk of being the first to test an unproven invention, particularly one that involves the crushing and suffocating environment of the sea. He was roughly thirty-four years old when it happened.

Among the Ill-Fated

John Day is remembered today primarily through his inclusion in a broader catalogue of inventors whose creations ultimately killed them. In the maritime category of this list, he stands alongside figures like Henry Winstanley, who was destroyed in the very lighthouse he built during the Great Storm of 1703, and Horace Lawson Hunley, who perished inside the submarine he engineered. Day's story is brief compared to theirs—just a carpenter and wheelwright from England, active in the mid-eighteenth century—but the underlying pattern is identical: a maker meets his end through the device he made. His entry serves as a quiet reminder that the history of technological progress is written not only in triumphs but also in the personal costs paid by those who dared to build the first versions of things that would later become commonplace. His life, spanning roughly 1740 to 1774, was cut short by the very ambition that drove him to look beyond the workshop and into the water.