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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

#211

Post by paulcole »

mapt wrote: post #208
gambiting wrote: post #184

Earlier quoted context omitted.

Re:solar - there was an experiment where they covered a whole tanker with solar panels. During the day, they provided 10% of power....needed to run the lights on the ship. Solar is just nowhere near good enough compared to the needs of a massive ship like this. Wind would maybe work, but then remember that a turbine would effectively slow you down as you'd be pushing against the air.

At perhaps 100 watts per square meter, a Maersk triple E ("An arbitrary large ship") at approximately 400 meters * 60 meters would generate 2.4 megawatts peak, or perhaps 400 kilowatts averaged. This is not nothing. It's roughly as much power as a redlined sports car engine. It might be sufficient to fight the worst ocean currents, since propulsion power scales so frighteningly faster than speed. https://www.maritime…

> This is not nothing. It's roughly as much power as a redlined sports car engine.

And a sports car is what, 3,000 pounds? A container ship is something like 200,000 tons. I guess they can power a redlining sports car engine when out to sea but not a whole lot else.

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

#212

Post by BurningFrog »

markdown wrote: post #205
abtinf wrote: post #85

Earlier quoted context omitted.

I'm not an expert in this topic - I've just read a few books and shipping was covered in a few of my upper division classes. They are the most important factors in the context of reliably shipping goods from port to port. If there was a sail technology that allowed reliable transit, predictable speeds and times (really slow is OK, a little late is not), and didn't cause an increase in other costs (say, insurance or m…

> The bottom left had things unprocessed ore, which have never made sense to ship. China mines and ships bauxite from Fiji to China. https://aluminiuminsider.com/bound-chinese-shores-fiji-ships...

Without knowing much of anything: Bauxite is a bit special in that aluminum processing is extremely energy intensive, and I think the ore is often shipped to places with low electricity prices.

It is one of the bigger industries in Iceland: https://www.nytimes.com/2017/07/01/us/politics/american-comp...

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

#213

Post by jillesvangurp »

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...

There are a few electric ships out there powered by batteries. They have a really short range though and of course a lot smaller than what Maersk needs.

A few examples of electrical ships:

https://phys.org/news/2017-05-norway-self-sailing-electric-c...

https://electrek.co/2017/12/04/all-electric-cargo-ship-batte...

I'm guessing battery cost rather than weight is the main issue here. The Chinese ship is powered by the equivalent of about 24 teslas apparently for a whopping range of 50 miles. Compared to the overal weight of these ships, I could imagine extended range with more batteries would be feasible. I imagine the capital expense is the bottleneck here; not the weight. But it makes a lot of sense for shorter routes.

Having solar and wind to supplement energy might help extend their range by a meaningful percentage but probably not enough to make it worth bothering since you in any case have to recharge frequently; which is probably comparatively cheap (compared to buying fuel)

Wind powered sail drones already exist as well: https://www.saildrone.com/ These are tiny of course but they can be out there for months by themselves. You could imagine a scaled versions of these transporting cargo. With no fuel cost and no staffing cost, you can get economies of scale by simply having more of them rather than bigger ones.

The reason big ships are popular today is that they minimize staff and fuel cost. Big ships require a lot of power but they are overall more cost effective per ton of load than smaller ones. If you take people and fuel cost out of the equation, you can start thinking about different solutions.

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

#214

Post by toomuchtodo »

johnnyletrois wrote: post #206
mabbo wrote: post #193

Earlier quoted context omitted.

Interesting perspective. I hadn't considered that. Part of me starts to wonder now about building boats that are more resilient, but then I remember that salt water is terrible and surely by now someone would have if it were possible, since we spend so much money on humans doing that maintenance!

If man can build it, the sea will destroy it.

Spoken like a true sailor :)

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

#215

Post by toomuchtodo »

dzhiurgis wrote: post #187
lozaning wrote: post #135

Earlier quoted context omitted.

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, t…

Ye old compass and lag wont get fooled by such mischievous act.

Electromagnet.

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

#216

Post by picsao »

ars wrote: post #105
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?

Slow is OK, but it must be exactly predictable. Don't be early, don't be late. So you can use sails to help, but if you rely on them you might be late.

Wouldn't then be on demand engines- tugdroneships along searoutes be ideal? Non of the weight sailing - all the speed on need.

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

#217

Post by runeks »

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…

> One of the painful early lessons for the industry was the discovery that minimizing operational costs (particularly fuel and maintenance) trumps every other value. A pioneering containerized shipping company went bankrupt pursuing a high-speed shipping strategy that cost marginally more than low-speed competition.

I’m not convinced that this is static — as far as I can see it should depend on the prevailing rate of interest. The more a company pays in interest on a loan, the faster it should want to realize its investment (which doesn’t happen by goods sitting in a container).

I’m not sure what the equilibrium interest rate is, exactly, but at some level of interest it should become cheaper to ship the goods faster, since you will save more in interest payments than the extra you pay for shipping (due to your investment becoming operational sooner, allowing you to pay back the loan).

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

#219

Post by telchar »

cwmoore wrote: post #60
telchar wrote: post #58

Earlier quoted context omitted.

Here's a source for you that mentions that even some typical formulations of stainless steel are susceptible to corrosion in saltwater: https://www.clintonaluminum.com/304-stainless-steel-in-seawa...

White bread is bad in saltwater too, that doesn't mean there aren't better materials for the application. https://www.quora.com/Does-aluminium-react-with-salt-water https://en.wikipedia.org/wiki/Organic_solar_cell

That's the point of the source you requested and I provided: there are some formulations of stainless steel that are actually kind of ok in salt water despite most being poor.

No one is arguing that it's impossible to build a bear with solar panels. The point is that you can't slap a cheap panel from Alibaba on a float and have any assurance that it will work reliably. Thus costs go up and the whole idea may become infeasible.

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

#220

Post by olejorgenb »

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.

I remember seeing this years ago. Wonder why it hasn't taken off. If their videos are honest in the ease of operation it looks like a great idea.
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