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

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

#151

Post by kdmytro »

jessriedel wrote: post #139
kenneth wrote: post #51

Earlier quoted context omitted.

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.

>> A point.

> No. Literally the same point, but in different words and with a feel of authority.

You should consider using words other than "No" if you agree with the point.

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

#152

Post by jabl »

Jsharm wrote: post #133

A little embarrassed to ask but why would normal sails not work?

I guess too labor intensive, and probably problems scaling up to the size of current ships. Consider the last generation of sailing cargo ships before steam took over (https://en.wikipedia.org/wiki/Windjammer ), those were around 2000-5000 GRT, compared to a big container ship today at something like 170000 GRT. The tonnage difference is rather massive.

Also, if you look at pictures of windjammers, masts, rigging etc., would get in the way of cargo handling. Less so on a tanker compared to, say, a container ship, of course.

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

#153

Post by nattaylor »

Timmah wrote: post #138

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.

Some fleets have implemented special bottom paint to reduce drag by reducing algae growth.

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

#154

Post by jessriedel »

jessaustin wrote: post #142
jessriedel wrote: post #139

Earlier quoted context omitted.

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

Reading the parent carefully, I find nothing that contradicts what you have written in response. Pressure is just force over area.

Thanks, upon re-reading I agree. I misinterpreted the "pushed from the back" statement.

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

#155

Post by sandworm101 »

mabbo wrote: post #103
jessewmc wrote: post #64

Earlier quoted context omitted.

Ignorant question: if operational costs trump all, especially fuel (Maersk says in the article 60% of operational cost) why not pure sail power? Is there some other maintenance cost or infeasability there? Or is there another hidden variable that is not satisfied?

I've long imagined some fun possibilities for this. I picture a small-ish shipping ship, say something moving 20 or 30 containers only, fully autonomous (100% crewless) with sails and solar only powering it. Solar electric motors handling the near-land operations and "not enough wind" conditions, sails otherwise. If you had autonomous loading and unloading, you would have zero variable/operational cost. I am certain…

Unless someone has spent time at sea they cannot appreciate all the maintenance a large ship requires. Crewless ships are pipe dream. But captainless ships, ships operated without officers to navigate them, are a real option. You keep the tiny crew for fixing things but the operation of the ship is handled from afar.

Crews are cheap. Ships' masters are not.

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

#156

Post by jessriedel »

kdmytro wrote: post #151
jessriedel wrote: post #139

Earlier quoted context omitted.

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

>> A point. > No. Literally the same point, but in different words and with a feel of authority. You should consider using words other than "No" if you agree with the point.

I misinterpreted his original point, which I intended to disagree with.

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

#157

Post by agumonkey »

kitd wrote: post #14
jessriedel wrote: post #10

Earlier quoted context omitted.

> Rotor ships take advantage of this same effect by spinning a large vertical cylinder, typically using an electric motor, and using the resulting force for propulsion. I always thought sails were partially defined by being passive. I wonder why these aren't called "rotor fans" if they're electrically driven? Is there anywhere it's discussed when rotors are expected to outperform normal fans? They seem to be used onl…

"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.

vortex wings ?

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

#158

Post by Someone »

rainbowmverse wrote: post #132
ams6110 wrote: post #83

Earlier quoted context omitted.

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?

I would think so, certainly of you add masts and sails that can propel that big a ship.

Example without sails: https://en.wikipedia.org/wiki/MSC_Napoli:

”during European windstorm Kyrill, severe gale-force winds and huge waves caused serious damage to Napoli's hull, including a crack in one side and a flooded engine room

[…]

the earlier grounding in 2001 did not contribute to the loss”

That ship was 62,000 tons. That’s not huge by today’s standards, but not small either.

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

#159

Post by lostlogin »

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.

Watching bleeding edge yachts sail is always interesting. Hydrofoils achieve speeds greater than 3x wind speed though their stability doing it is a bit alarming.

https://www.odt.co.nz/sport/yachting/how-fast-can-americas-c...

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

#160

Post by Faaak »

ethagknight wrote: post #97
mvpu wrote: post #91

Wonder why ships aren't trying solar panels and electric motors and auto-pilot... they're out in clear Sun, have a large surface area, and no traffic...

Two problems with boats and solar propulsion: 1) they need 24/7 power. 2) Using a random LG 330 W panel on top of the Edith Maersk, it would take an array 1/3 of a mile by 1/2 of a mile in area to match Edith's 80,000 kW engine power output. Edith is 1/4 mile long and 3/100ths of a mile wide. Quite a gap, and thats before you start factoring in batteries for the night, structure to support the array, storms...

Though you could power the ship from solar during the night and with diesel generators during the night.
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