Ben Franklin’s One Simple Trick to Save Sailors from Drowning

On April 20, 2010, the Deepwater Horizon, an offshore oil rig operating in the Gulf of Mexico exploded. Eleven people died in the explosion, and the environmental damage was immense — more than 200 million gallons of crude oil spilled into the Gulf, requiring as much as $100 billion (inflation-adjusted) to clean up. If you were around when this happened, you probably know that it’s a really, really bad idea to dump crude oil into the ocean.

But olive oil? Or fish oil? Not only is that fine, but — as ten sailors from the late 1800s could have attested — it may also save lives. And they may have had Ben Franklin to thank for it.

Franklin is famous for many things — he was a Founding Father of the United States, the nation’s first Postmaster General, a prolific inventor, and more. He was also insatiably curious, with many examples of him appreciating in awe the details of the world around him, and then setting out to learn more. The example of note today came at some point during his travels — most sources say 1757 — Franklin was on a ship in the Atlantic, and noticed that the water behind the ship wasn’t as rough as the surrounding seas. He investigated and found that small amounts of cooking oil from the ship’s galley had leaked into the water behind them, and for some reason, the oil-tainted ocean water turned calm, creating a glassy effect. He wasn’t sure why, and likely never fully understood the science, but he was intrigued and wanted to learn more.

As he wrote in a November 1773 letter, he made a point of carrying some oil with him so he could replicate the effect, and found that it almost always worked: “After this, I contrived to take with me, whenever I went into the Country, a little Oil in the upper hollow joint of my bamboo Cane, with which I might repeat the Experiment as Opportunity should offer; and I found it constantly to succeed.” (There are claims that Franklin used this specialized knowledge to prank people, convincing them he could calm waves with a simple tap of his cane.) He kept sharing this discovery and developed a theory — he believed that, for some reason, the oil was reducing the friction between the wind above and the water below. And he was mostly right.

What Franklin had discovered was nothing new. For example, centuries earlier, Greek philosopher Aristotle observed that divers had spread oil over their eyes to “quiet the surface and permit the rays of light to reach them,” per Wikipedia’s editors. But Franklin is typically credited with first articulating the scientific principle behind the phenomenon and helping knowledge of it spread. Let’s jump into the science first.

In this video by PBS’s science program, Nova, we get to see the experiment in action. You should watch the video, but in case you can’t right now, here’s the gist. The host goes out on what appears to be a lake with a bottle of olive oil, and measures out one tablespoon of the liquid. He then dumps the small amount of oil into the water and waits. Ten minutes later, the oil has spread out a great distance, covering about half an acre. As seen in the screenshot below, the water in the lake is moderately rough, but the area covered by oil is glassy and smooth.

As the show’s host explains, “when you put oil on water, the oil molecules flip onto their negatively charged heads because they’re attracted to positively charged parts of the water molecules.” The oil molecules spread out so that every molecule in that tablespoon of olive oil can touch the water this way, and you end up with a layer one molecule thick. That’s why the oil spreads so far — but not why the waters in that area are so calm. Nova continues: “usually, the wind builds up waves by getting traction on the surface of the water,” just like Franklin suggested. But in this case, per Nova, “the oil acts like a tangled, shaggy carpet on the water, which doesn’t bend or stretch easily, so instead of making waves, the wind just drags the carpet across the water.” Sooner or later, the oil will wash ashore, with no harm done — it’s just a tablespoon of olive oil, after all. But in the interim, the oil-covered water makes for smooth sailing.

And that can be a literal lifesaver. In 1883, nearly a century after Ben Franklin died, a merchant ship named the Grecian was on its way to Portugal from Philadelphia. Along the way, it ran into a storm, and as the Scripps Institution of Oceanography recounts, the ship “had been damaged in a storm five days out of port, and began taking on water.” A sailing ship, the Martha Cobb, was nearby, but it was unable to mount a rescue operation — per Scripps, “the stormy ocean had destroyed life boats on both of their decks, leaving only a dinghy for the Martha Cobb to use in a rescue attempt. [The shipmaster of the Martha Cobb, Thomas] Greenbank judged that the dinghy would be destroyed if it were cast into the breaking seas and decided to wait for conditions to improve.”

They didn’t, but Greenback remembered Franklin’s trick. (Whether he learned it, directly or otherwise, from Franklin is unknown.) He broke out the oil. At first, per Earth Magazine, the crew of the Martha Cobb “pumped petroleum from the ship into the ocean. This did little to calm the breaking waves, however, because petroleum does not spread effectively enough on the surface of water to form a continuous film on the sea.” (That’s also why crude oil won’t work for this, but it does make a huge mess.) For their second attempt, they dumped 19 liters of fish oil into the waters, which, like olive oil, is chemically rather simple and spreads easily.

About 20 minutes later, that oil had spread all the way to the Grecian. As the Grecian began to sink, the dinghy from the Martha Cobb was able to make two trips to the doomed craft, saving all aboard.

Bonus fact: A winter’s breeze isn’t likely to get you sick, unless you’re downstream of someone who just sneezed some virus into the wind or something like that. But there are still people who believe otherwise, and that fear was common in the late 1700s. John Adams, the second President of the United States, was one of those people who feared the night’s wind, and, according to Mental Floss, refused to sleep with the window open. That wouldn’t have been a problem in most cases but in September of 1776, he and Ben Franklin were on a trip to negotiate with the British and stopped for the night in New Brunswick, New Jersey. Adams and Franklin had to share a room, and Franklin wanted to sleep with the window open. The two argued and Franklin won — but not because he convinced Adams of his position. Rather, Adams fell asleep and Franklin took advantage of the situation and opened the window.

From the Archives: How Ben Franklin Killed the Competition: Via literature, but not literally.