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A comment on Wind-powered ships are making a comeback.

Re:Wind-powered ships are making a comeback by escherplex on Sunday October 07, 2018 @02:48PM (#18162028)
This idea was already broached at HN in

Maersk installed 100-foot-tall rotating sails on one of its tankers

https://news.ycombinator.com/item?id=17885284

But a question arises as to practicality of this configuration in extreme weather at sea. That's a lot of wind swept area aloft abovedeck. In extreme weather conditions with rolling seas, an elongated cargo vessel such as a tanker will be subject to sagging (central portion suspended in space between two wave crests). Given strong head or tail wind force imposed on tall rotor shafts it would seem that extra torque would be imparted on the central section increasing the liklihood of hull failure under full cargo load.

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Re:Wind-powered ships are making a comeback by gehsty on Sunday October 07, 2018 @03:17PM (#18162163)
Fairly sure this is an naval architecture problem a company of Maersk scale would be able to solve. There may be additional strengthening installed whilst the sails are installed. Seems like a ‘use more steel’ type problem.
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Re:Wind-powered ships are making a comeback by escherplex on Sunday October 07, 2018 @03:29PM (#18162218)
Yeah, presumably so. But most articles of this sort tend to be more like one-sided sales pitches. Personally, I'd fall over if I saw an article which adopted a Kantian 'thesis' 'antithesis' ergo suggested 'synthesis' approach.
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Re:Wind-powered ships are making a comeback by gehsty on Monday October 08, 2018 @05:06AM (#18165584)
Is that smart way of saying present both sides of the argument? I tend to work in 'more steel' type problems ;)
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Re:Wind-powered ships are making a comeback by pasabagi on Sunday October 07, 2018 @04:47PM (#18162529)
Hegelian, you mean. Kantian argument would be pretty boring, as it's typically exhaustive.
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Re:Wind-powered ships are making a comeback by escherplex on Sunday October 07, 2018 @04:59PM (#18162574)
Exhaustive to the extent practical would be nice :)
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Re:Wind-powered ships are making a comeback by qbrass on Sunday October 07, 2018 @06:28PM (#18162957)
You quit spinning the rotors and they stop acting like a sail.
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Re:Wind-powered ships are making a comeback by infogulch on Sunday October 07, 2018 @07:26PM (#18163175)
I wonder if they have enough rotational inertia to cause gyroscopic effects while they're spinning. I wonder if it could be used to stabilize the ship. Or it causes more issues than it solves you can just stop spinning it, just like you can stop it to stop it acting like a sail.
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Re:Wind-powered ships are making a comeback by ansible on Sunday October 07, 2018 @07:53PM (#18163265)
Without running the numbers, just looking at the mass of the sail vs. the mass of the ship, is say the effect is neglible.
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Re:Wind-powered ships are making a comeback by marmadukester39 on Sunday October 07, 2018 @08:41PM (#18163410)
I know of a company that makes these as retractable spinning cylinders
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Re:Wind-powered ships are making a comeback by JoBrad on Sunday October 07, 2018 @08:57PM (#18163474)
The PDF that @danielvf posted mentions gyroscopic benefits on page 20.
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Re:Wind-powered ships are making a comeback by knieveltech on Sunday October 07, 2018 @08:14PM (#18163329)
In heavy enough weather it's possible to drop sail entirely and still make way on a bare mast, so nah, they might act less like a sail, but they don't stop entirely.
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Re:Wind-powered ships are making a comeback by canam on Monday October 08, 2018 @09:44AM (#18167332)
In heavy weather a sailboat sails under bare poles. However, it might actually be a stabiling force in rough seas. My sailboat is far more stable with the sails up. Side to side rolling is eliminated.
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Re:Wind-powered ships are making a comeback by strainer on Sunday October 07, 2018 @03:08PM (#18162123)
I would guess that the bending and twisting pressures of swelling and crashing water, rather dwarfs the potential forces the cylinders can drag through air in a storm, especially while they are not spinning. And I'd guess they would be engineered to break off, before harming the hull if that could be a threat.
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