Hacker News Board Hacker News, browsed like a classic message board
Live data from Hacker News

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

wsj.com

Post reply on HN
Print view View original

121–130 of 233 posts

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

#121

Post by chooseaname »

cwmoore wrote: post #30
village-idiot wrote: post #21

Earlier quoted context omitted.

I think the issue would be salt water. Salt water destroys everything , I can’t imagine that a PV array floating in water would have a good life expectancy. On the plus side, if the insulation fails you could turn container ships into accidental fishing boats.

> 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…

How would you keep them clean enough to produce optimal output? Every drop of salt water would quickly dry and leave a salty residue. How do you clean that while at sea?

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

#122

Post by Maybestring »

alonmower wrote: post #111
mabbo wrote: post #103

Earlier quoted context omitted.

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…

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.

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

#123

Post by eanzenberg »

factsaresacred wrote: post #34

Copying the first comment from WSJ 'cause it's interesting: > These are known as Flettner rotors after the German engineer Anton Flettner who invented them and made the first rotor sailing ship in 1924, with one sailing one across the Atlantic in 1926 - and they are not turbo sails. They have generally been in disuse as it has been deemed that the energy expended in propulsion by Flettner rotors was higher than that…

>> An interesting note, Flettner was considered so valuable to the Germans in WW2 that Heinrich Himmler, the head of the Gestapo saw to it that Flettner's Jewish wife was escorted to Sweden for her safety for the duration of the war.

That's nice and all but he still helped the nazis with military research while many of his colleagues fled, Einstein included.

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

#124

Post by PeterisP »

cwmoore wrote: post #107
village-idiot wrote: post #96

Earlier quoted context omitted.

Throw out a speculative idea, get a speculative answer. Dunno why you’re expecting me to go all civil engineer on you, nor do I understand why you’re acting like I’m the barrier to the idea being tried. Go do the math yourself, it’s your idea.

It wasn't my idea. My idea was that it shouldn't be dismissed for the reason you presented without a citation.

What can be asserted without evidence can also be dismissed without evidence.

As there's a well known consensus that some factor (e.g. saltwater caused maintenance issues in this particular case) tends to be a game-breaker, then it's perfectly reasonable to dismiss 'without a citation' ideas that encounter this factor if the idea has no mention/citation of how they're going to fix, avoid or tolerate this.

If there's a plausible-seeming way that the idea can work despite the obstacle, then by all means we can discuss if that way will be sufficient or not; but if the idea simply ignores major problems, then there's nothing to discuss.

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

#125

Post by dscpls »

wenc wrote: post #117
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 wonder: do sails alone generate enough power to move today's massive container ships? Or would the ships need to be smaller?

There's no question sails can move today's cargo volume. But the shape of the ships doesn't lend itself to sail power. I think these sails are specific to supporting other power. And the shape of today's ships is very much towards fitting more cargo. I think you'd need at least slightly bigger ships that are efficient for sail power alone, and able to carry similar cargo volume or mass.

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

#126

Post by fasteddie »

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…

The reason autonomous/crewless isn't really feasible or worth investing in is that most container ships only have a crew of about a dozen, and they are generally from low-wage countries so that their salary costs are far out-weighted by the fuel.

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

#127

Post by cwkoss »

village-idiot wrote: post #22
IB885588 wrote: post #8

Another option is skysails (giant kites that drag the ship forward): https://en.wikipedia.org/wiki/SkySails Hopefully someday almost all ships have a mix of these things + maybe run on algae-based advanced biofuels or something like that.

Hydrogen fuel cells are looking likely. Solar will probably produce too much electricity for usage during the day, so use that spare energy to split water to create Hydrogen fuel.

Isn't hydrogen difficult to store? I've heard that it will leak out of just about everything.

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

#128

Post by bobowzki »

fmsf wrote: post #2

It's called the Flettner rotor, it uses the Magnus Effect. Cool stuff but not exactly new tech. It gives a nice read, here's some links to wikipedia on the topic: https://en.wikipedia.org/wiki/Magnus_effect and https://en.wikipedia.org/wiki/Rotor_ship I'm curious of what will be the results.

First ship was built 1924 so it's almost 100 years old tech by now. Still cool though.

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

#129

Post by JamesCoyne »

This led me to wonder how important height was a restriction on ships. Turns out "air draft" is reported for major ports.

Some interesting findings: The Panama Canal has an air draft of 201 ft imposed by the Bridge of the Americas; the Port of Oakland has an air draft of 220 ft imposed by the Golden Gate Bridge.

Height from waterline does not appear to be typically listed for ships, but I would guess that most cargo vessels do not have 100 ft of clearance to spare. I think this means these sails would only be fitted to vessels which generally don't care about height restrictions (e.g. ships larger than Panamax) or ships running predictable routes.

https://en.wikipedia.org/wiki/Air_draft

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

#130

Post by cwmoore »

chooseaname wrote: post #121
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…

How would you keep them clean enough to produce optimal output? Every drop of salt water would quickly dry and leave a salty residue. How do you clean that while at sea?

I am not the author of the original comment, but I really like the concept. From what I understood this would be floating at surface level and would be continuously washed over by surface water.

There are many good objections. It may be that the original comment does not illustrate the promise of this energy platform very thoroughly.

Post reply on HN