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Spinning Metal Sails Could Slash Fuel Consumption, Emissions On Cargo Ships (sciencemag.org)
sciencehabit shares a report from Science Magazine: U.K. soccer star David Beckham was known for "bending" his free kicks over walls of defenders and around sprawling goal tenders, thanks to a physical force called the Magnus effect. Now, the physics behind such curving kicks is set to be used to propel ocean ships more efficiently. Early next year, a tanker vessel owned by Maersk, the Danish transportation conglomerate, and a passenger ship owned by Viking Line will be outfitted with spinning cylinders on their decks. Mounted vertically and up to 10 stories tall, these "rotor sails" could slash fuel consumption up to 10%, saving transportation companies hundreds of thousands of dollars and cutting soot-causing carbon emissions by thousands of tons per trip.
Rotor sails rely on a bit of aerodynamics known as the Magnus effect. In the 1850s, German physicist Heinrich Gustav Magnus noticed that when moving through air a spinning object such as a ball experiences a sideways force. The force comes about as follows. If the ball were not spinning, air would stream straight past it, creating a swirling wake that would stretch out directly behind the ball like the tail of a comet. The turning surface of a spinning ball, however, drags some air with it. The rotation deflects the wake so that it comes off the ball at an angle, closer to the side of the ball that's rotating into the oncoming air. Thanks to Isaac Newton's third law that every action must have an equal and opposite reaction, the deflected wake pushes the ball in the opposite direction, toward the side of the ball that's turning away from the oncoming air. Thus, the spinning ball gets a sideways shove.
Rotor sails rely on a bit of aerodynamics known as the Magnus effect. In the 1850s, German physicist Heinrich Gustav Magnus noticed that when moving through air a spinning object such as a ball experiences a sideways force. The force comes about as follows. If the ball were not spinning, air would stream straight past it, creating a swirling wake that would stretch out directly behind the ball like the tail of a comet. The turning surface of a spinning ball, however, drags some air with it. The rotation deflects the wake so that it comes off the ball at an angle, closer to the side of the ball that's rotating into the oncoming air. Thanks to Isaac Newton's third law that every action must have an equal and opposite reaction, the deflected wake pushes the ball in the opposite direction, toward the side of the ball that's turning away from the oncoming air. Thus, the spinning ball gets a sideways shove.
... it seems we have come full circle on ship propulsion technology.
There is no XUL, only WebExtensions...
Personally, I enjoyed this review:
I wish I'd read this highly informative title in the late 90s. My husband and I both suffer from PTHSCD (post-traumatic huge ship collision disorder) which we acquired while piloting our own huge ship. I remember it like it was yesterday -- we were carrying over 3 million gallons of blue paint to Morocco when, wouldn't you know it, we collided with our competitors. They had about 4 million gallons of red-brown on board, and before we knew it, we were all marooned.
This one was also quite a helpful review:
When on my jet ski in the Chesapeake bay this summer I was confronted by a huge ship moving up the channel. You can imagine my horror when I realized I had only 1 hour and 45 minutes or so before the lumbering behemoth was sure to pass through my area. With no place to hide and only a water jet propelled small craft beneath me for transport, I quickly withdrew my Kindle Fire from the storage compartment beneath my seat and preceded to read the book How To Avoid Huge Ships. One hour later and with only 45 minutes to spare, I implemented the expert advice provided by the author and turned my jet ski in the opposite direction of the huge ship to avoid certain disaster.
Irony: Agile development has too much intertia to be abandoned now.
I've heard that the United States Navy has just put in a special expedited order for 50,000 copies of this book.