Martha Coston was an American inventor in the 19^th Century, and played a pivotal role in making maritime exploration and sailing significantly safer thanks to her improvement of one of the most important inventions in maritime history: the signal flare.

How Martha Coston Made Sailing Safer:

The concept of using explosives to act as signals had been around since the 13^th century. Chinese signal bombs were launched into the air for carefully timed explosions, which could be used to convey simple messages.

By 1600, Korea already had working signal guns. However they didn’t last long enough to be seen at great distance, and couldn’t communicate complex messages.

At just 21, Martha Coston found herself newly widowed with children to support. Her late husband had been a scientist, heading up the Navy’s pyrotechnics division. While going through his belongings, she found notes detailing a signal flare for the Navy. Her husband’s design, however, did not work as well as it could. She noted the flares were not bright enough, nor did they last long enough to be seen from far away.

She realised she could improve the design and functionality of the flares by creating stronger ones in different colours, that would allow for different combinations of colours that could signify different meanings. She utilised pyrotechnics found in fireworks to improve the luminosity. She only had a limited knowledge of chemistry, so had to enlist the help of various experts who advised her on how best to improve the existing designs of her late husband. While it took a long time to perfect, the formula she decided on is still largely the same as the one used in roadside flares today.

Why The Signal Flare Is So Important To The Marine Sector:

To help test her idea, a friend drove up to a mountain five miles away from where she lived, and reported that they could see the flare clearly. Her new designs meant the signals could be used for both ship-to-ship and ship-to-land communications across large distances.

In 1859 she would patent her new signalling systems using flares of red, white, and green, calling them ‘Night Signals’. They could be applied to any of the already existing Naval Codes by firing off in different orders of colours, meaning they can effectively communicate letters and numbers.

The US Navy paid her $20,000 to take the idea, and used it during combat. They also gave Martha a contract to continue work on the flare technology and continue manufacturing them. Over the course of the American Civil War, Coston’s company sold over a million flares to the Navy, which saved many lives. They would go on to be adopted by the wider marine community over the following years, becoming crucial in search and rescue operations.

Martha continued to improve her designs, and set up a business, The Coston Supply Company, which continued operating until the 1980s. In 2006 she was inducted into the National Inventor’s Hall of Fame.

Read about other historical figures in engineering like Hedy Lemarr, or learn about how the marine sector has become safer over the years.