Sailboats are back, but this time the sails are spinning.
The next time you see a hulking cargo ship plying the ocean, you could be looking at a sailboat. The shipping industry has begun to experiment with rotating towers that can be installed on ships to harness wind, but in a much more high-tech way than rigging up canvas.
These spinners are called rotor sails, and they take advantage of a physics quirk to push a boat forward. You might recall the Magnus Effect from demonstrations such as throwing a basketball with a lot of backspin from the top of a towering dam. Basically, a spinning object such as this creates a pressure imbalance, and lower pressure on one side of the rotor can help to propel a vessel.
Rotor ships, sometimes called Flettner ships, have been around a while. The big development now is that the major players in shipping are taking the idea seriously. Yesterday the shipping colossus Maersk installed 100-foot-tall rotors on one of its tankers, the Pelican, according to the Wall Street Journal.
Maersk thinks the advanced sails could cut its fuel costs by 10 percent. That may not sound like much, but consider that the Danish mega-corporation spends $3 billion annually on fuel to move the world’s cargo, so we’re talking about $300 million. If the Pelican tests succeed, the Maersk could try out rotors on other vessels and turn more cargo ships into hybrid sailboats.
Why now? According to the WSJ:
“Shipping executives said previous efforts didn’t catch on with operators because either the costs of such technologies were too high or tests didn’t yield the expected fuel savings. But modern, lightweight and relatively cheap rotating sails show more promise, they said.”
Previously published by: Popular Mechanics USA