Who Invented the Signal Flares Used by Ships?

Signal flares are standard safety equipment for watercraft worldwide. But do you know who made this invention a reality back in the 1850s? The answer is a persistent problem solver who became a National Inventors Hall of Fame^® Inductee: Martha Coston. 

Uncovering a Promising Idea

Coston was born Martha Hunt in Baltimore in 1826. She married Benjamin Franklin Coston, an inventor who had worked as a naval scientist at the Washington Navy Yard, but early in their marriage, Benjamin’s health began to decline due to chemical exposure at work.

Following the death of her husband in 1848, Coston also tragically lost two of her children, as well as her mother. Without familial support, Coston found herself at the edge of poverty. She knew she needed to find a way to support herself and her remaining children. 

When Coston began looking through her late husband’s papers, she came across a set of notes providing an outline for a signaling system that involved color-coded flares. Though these notes did not include any details on how the system might be created, Coston believed she could turn this initial design idea into a successful reality. 

Bringing an Invention to Life

For more than a decade, Coston devoted herself to building the skills she would need to develop a working signal system. She taught herself about pyrotechnics and chemistry, how to establish and manage her own company, and how to work with government agencies. Perhaps most importantly, she also learned how to protect her intellectual property.

In 1858, Coston found some colorful inspiration for her signal system as she enjoyed fireworks that had been set off in celebration of the first transatlantic cable in New York City. She decided to develop flares that would burn red, white and blue. As she worked to develop flares in each color, Coston was successful with red and white, but blue flares proved especially challenging to create. Undeterred, she decided to develop bright green flares instead. 

The patent for Coston’s signal system, featuring red, white and green flares, was issued in 1859. Coston was named as administrator of the patent, and her late husband was named the inventor.

Making a Global Impact

Having secured a patent, Coston established the Coston Manufacturing Co. As she began selling her signal flares, the U.S. Navy recognized that because the flares were bright, long lasting and could be used in coded combinations of colors, they offered significant advantages for both ship-to-ship and ship-to-land signaling over long distances. Throughout the Civil War, the Coston Manufacturing Co. sold the signals to the U.S. Navy at cost.

The Coston signal flare became an international success as standard safety equipment for watercraft. In addition to the U.S. Life Saving Service (which later became the U.S. Coast Guard), the U.S. Weather Service and military institutions around the world, private yacht clubs and commercial merchant vessels also used Coston’s ingenious signal flares. 

Through her perseverance and dedication as an inventor and entrepreneur, Coston not only achieved her goal of independently supporting her family, but she also ensured that her business would continue to flourish until the late 20th century. 

Meet More Visionary Inventors 

More than 650 creators, innovators and entrepreneurs have been inducted into the National Inventors Hall of Fame. To discover more of their stories, keep exploring our website.