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

wsj.com

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

#131

Post by cwmoore »

jacquesm wrote: post #39
cwmoore wrote: post #30

Earlier quoted context omitted.

> Salt water destroys everything This is the statement I hear relating to all kinds of ocean-based renewable energy ideas. Sources are never provided. The problem must have to do with economic viability and the replacement/maintenance costs exceeding savings. Could you supply sources to elaborate on where the break even point of solar tail (or any two other ocean renewable energy) systems would be as relates to costs…

> Sources are never provided. We also do not need to provide sources for statements such as 'water is wet'. Anything on a boat, or even shoreside near to the ocean is subject to corrosion and corrosion protection is a serious maintenance issue. I've lived 2 km from the sea and even there the nails would rust right out of the building due to the salt that the wind would carry in.

My request was not intended to be asking for sources about corrosion, but for sources as to why corrosion should be the limiting factor. I would edit it to lead with the question it asks in the third line, if it weren't now too late.

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

#132

Post by rainbowmverse »

ams6110 wrote: post #83
empath75 wrote: post #68

Earlier quoted context omitted.

unpredictability of wind, i'd imagine.

That and storms. You need engines to ride out or (better) avoid storms at sea.

Is a ship that big bothered by anything less than a hurricane?

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

#135

Post by lozaning »

Maybestring wrote: post #122
alonmower wrote: post #111

Earlier quoted context omitted.

No hostages for pirates to take either (though I guess they could help themselves to all of the goods on the ship)

And the ships. Drop an anchor and demand ransom to cut it free.

Even easier, just spoof the GPS signals with your own higher powered broadcast and make the ship think it's sailing around while it's actually stationary. Cant find the link but, some university actually demoed this working in real life with an actual container ship.

Im imagining an LED throwie type big magnetic thing with gps RX and TX, and a satellite uplink. Cruise by the autonomous ship on a jetski near a port, thrown the magnet thing on, jetski away, disrupt from afar once the boat is out at sea.

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

#136

Post by ars »

danaos wrote: post #52
jacquesm wrote: post #35

Earlier quoted context omitted.

> You are, unfortunately, incorrect. No, you are, unfortunately, incorrect. > Without tacking, no wind power systems will help when going straight upwind. https://en.wikipedia.org/wiki/Windmill_ship

He was right that "The Magnus effect doesn't gain you anything other than the helpful drag of a tall cylinder when going in the same direction as the wind." In fact, the Magnus rotors will not provide any usefull thrust is both upwind and downwind scenarios. https://en.wikipedia.org/wiki/Rotor_ship#/media/File:Points_...

> In fact, the Magnus rotors will not provide any usefull thrust is both upwind and downwind scenarios.

If the wind is coming from behind won't it simply push the stationary cylinder, adding some thrust?

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

#138

Post by Timmah »

Would be excited to see this technology combined with the "underbelly bubbles" technology that I heard about a few years ago where they reduce drag by releasing air bubbles under the hull. Yeah it takes energy to do it but the decreased resistance is supposedly a net gain. Two 10% gains would be awesome.

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

#139

Post by jessriedel »

kenneth wrote: post #51
kitd wrote: post #14

Earlier quoted context omitted.

"Fan" implies the propulsion is in response to air being forced backwards. These rotors create lift in a forwards direction from the wind blowing across them, a bit like having a fixed wing pointing up.

Regular sails actually work similarly to a wing, in that pressure differentials on either side create a force we call lift on a plane, rather than simply being "pushed from the back" by directly catching the wind. That's why a sailboat can go in almost any direction regardless of which direction the wind is blowing.

Edit: sorry, nevermind, I was confused as to what you were claiming.

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

#140

Post by jessaustin »

abtinf wrote: post #18

Some years ago I read The Box by Marc Levinson, a history of containerized shipping. Highly recommend it. If you live in SF and have wondered about the numerous barely used piers, this book explains their history as well - and why the major container terminal ended up in Oakland instead. One of the painful early lessons for the industry was the discovery that minimizing operational costs (particularly fuel and mainte…

...why the major container terminal ended up in Oakland instead.

Whatever the reason, I'm sure everyone who uses a bridge in SF is happy about this.

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