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Future sailors: what will ships look like in 30 years?

theguardian.com

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Re: Future sailors: what will ships look like in 30 years?

#41

Post by soperj »

forapurpose wrote: post #39
krschultz wrote: post #15

As someone that has designed (military) ships, here are my thoughts. - LNG is definitely happening, and that alone will make a massive difference in emissions. - No shit smoother bottoms and bulbous bows are better for efficiency, that's been standard practice for decades and large cargo ships are generally not that old. - Counter rotating props are interesting, I could see that being a big win but the mechanical com…

> LNG is definitely happening, and that alone will make a massive difference in emissions An important, if often repeated point: Natural gas reduces emissions at the point of consumption; that may be balanced out by higher climate change impact when it's mined. If someone has good, conclusive information on that issue, it would be appreciated.

Based on what? Lots of Natural gas was just released into the air at oil fields before they started capturing it for sale.

Re: Future sailors: what will ships look like in 30 years?

#42

Post by forapurpose »

killjoywashere wrote: post #17
gk1 wrote: post #2

I'm excited but skeptical. Energy-saving concepts have been around for a long, long time. For example, I first heard about the use of kites[1] over a decade ago, yet the company that makes them is struggling to stay afloat. The issue is that commercial ships are very expensive to build, even using parametric design — where you basically plug in your desired cargo capacity and get a complete blueprint in return. Also,…

And, I have to say, as a navy surface officer, I don't see how much of any of this is going to change the sailor's life. Living on a working ship is a bit like being a mouse on the deck of a lawnmower. For all intents and purposes, you're in the machine, and it will kill you.

> I don't see how much of any of this is going to change the sailor's life

While sailors' lives are important in themselves, what do you see as the connection to the issue at hand, reducing climate change impact?

> it will kill you

Every sailor dies? I don't understand what you're getting at.

Re: Future sailors: what will ships look like in 30 years?

#43

Post by gk1 »

Retric wrote: post #21
krschultz wrote: post #15

As someone that has designed (military) ships, here are my thoughts. - LNG is definitely happening, and that alone will make a massive difference in emissions. - No shit smoother bottoms and bulbous bows are better for efficiency, that's been standard practice for decades and large cargo ships are generally not that old. - Counter rotating props are interesting, I could see that being a big win but the mechanical com…

What about solar? I know it does not scale down very well or work for the military, but solar seems useful for the largest ships. MV Barzan is a container ships that's 400 m x 58.6 m. If you take say 400m x 50m * 24% solar panels that's ~6500 HP in full sun. I know the engines are significantly larger than that but not sure how much they use at cruising speed.

That is not nearly enough. These ships are heavy. To put it into perspective, 6,500 HP would be just enough to meet half the auxiliary power demand (eg, HVAC, electrical, motors, etc) on the 500-foot training ship I sailed on, which is a toy compared to commercial ships. Propulsion required a 60,000+ HP steam power plant.

Re: Future sailors: what will ships look like in 30 years?

#44

Post by tzs »

A lot of ship cargo consists of things that (1) we need a steady supply of, and (2) have a very long shelf life. For such cargo it doesn't matter how long the transit time for any particular shipment is, as long as shipments are arriving at the destination often enough.

I wonder if we could make unmanned cargo boats that spend most of their time drifting?

Drifting can be quite effective at long distance ocean transport. For an example look at the Friendly Floatees accident [1]. A ship accidentally lost 29 000 floating bath toys in the middle of the Pacific. Over the next 15 years they reached land in on both the Pacific and Atlantic coasts of North America, the Pacific coast of South America, Australia, and Europe, and came close to Japan.

I'm imagining a ship that drifts, occasionally using an engine to get into known currents that will help it toward its goal or avoid currents known to hurt.

Places where two or more significant currents pass through the same region could be used to route traffic. They could have tow ships stationed there that can move drifters between the currents

We could have a large fleet of such drift ships carrying suitable commodities with very little environmental impact, with a smaller fleet of normal cargo ships providing fast transport to fill in the gaps caused by the randomness of the drifting fleet arrivals.

The above idea is based on the proposals I've seen to do something similar in space. Briefly, there are orbits that can move an object from Lagrange points of one pair of bodies to Lagrange points of another pair using very little energy, but they can take a very long time.

The proposals are to start using those to regularly send supply ships to various moons and planets that we think we may want to send humans to later. Suppose the path to some particular moon takes 30 years. If we start sending supply ships down that path now, sending one every 6 months, say, then 30 years from now they start arriving. Then we can send the humans. The ship with the humans only needs to take enough supplies for the trip out, making the trip much more feasible.

[1] https://en.wikipedia.org/wiki/Friendly_Floatees

Re: Future sailors: what will ships look like in 30 years?

#45

Post by brandmeyer »

forapurpose wrote: post #39
krschultz wrote: post #15

As someone that has designed (military) ships, here are my thoughts. - LNG is definitely happening, and that alone will make a massive difference in emissions. - No shit smoother bottoms and bulbous bows are better for efficiency, that's been standard practice for decades and large cargo ships are generally not that old. - Counter rotating props are interesting, I could see that being a big win but the mechanical com…

> LNG is definitely happening, and that alone will make a massive difference in emissions An important, if often repeated point: Natural gas reduces emissions at the point of consumption; that may be balanced out by higher climate change impact when it's mined. If someone has good, conclusive information on that issue, it would be appreciated.

People mean different things whey they talk about emissions. Shipping is particularly dirty because of the low-grade fuel that they've been using. Its very high in sulphur content, and typically contains a higher fraction of heavier compounds that don't burn as well.

So the ships produce more unburned hydrocarbons (smog precursors) and sulphur oxides (acid rain precursors).

So even if the total CO2 emissions are similar, the other toxics are still greatly reduced.

Re: Future sailors: what will ships look like in 30 years?

#47

Post by scrumbledober »

Retric wrote: post #21
krschultz wrote: post #15

As someone that has designed (military) ships, here are my thoughts. - LNG is definitely happening, and that alone will make a massive difference in emissions. - No shit smoother bottoms and bulbous bows are better for efficiency, that's been standard practice for decades and large cargo ships are generally not that old. - Counter rotating props are interesting, I could see that being a big win but the mechanical com…

What about solar? I know it does not scale down very well or work for the military, but solar seems useful for the largest ships. MV Barzan is a container ships that's 400 m x 58.6 m. If you take say 400m x 50m * 24% solar panels that's ~6500 HP in full sun. I know the engines are significantly larger than that but not sure how much they use at cruising speed.

How unfeasible would folding solar panel arrays be? The ship could fold them out like a satellite once they left port if the seas were favorable.

Re: Future sailors: what will ships look like in 30 years?

#48

Post by brandmeyer »

bluGill wrote: post #22
krschultz wrote: post #15

As someone that has designed (military) ships, here are my thoughts. - LNG is definitely happening, and that alone will make a massive difference in emissions. - No shit smoother bottoms and bulbous bows are better for efficiency, that's been standard practice for decades and large cargo ships are generally not that old. - Counter rotating props are interesting, I could see that being a big win but the mechanical com…

I would expect counter rotating props to be more reliable. Instead of one big engine/prop you have two smaller ones. While it is more likely that something will break, it isn't a catastrophic failure: you continue to your destination using just the other engine/prop.

Just because you replaced 1 thing with 2 things doesn't mean you've increased the system's reliability. In this case, you've also added a lot of complexity in the shafts, seals, and gearboxes. That means more things that can go wrong. Most of those things can affect both screws when they fail, so there isn't any gain in reliability due to redundancy at all.

Re: Future sailors: what will ships look like in 30 years?

#49

Post by whatshisface »

forapurpose wrote: post #39
krschultz wrote: post #15

As someone that has designed (military) ships, here are my thoughts. - LNG is definitely happening, and that alone will make a massive difference in emissions. - No shit smoother bottoms and bulbous bows are better for efficiency, that's been standard practice for decades and large cargo ships are generally not that old. - Counter rotating props are interesting, I could see that being a big win but the mechanical com…

> LNG is definitely happening, and that alone will make a massive difference in emissions An important, if often repeated point: Natural gas reduces emissions at the point of consumption; that may be balanced out by higher climate change impact when it's mined. If someone has good, conclusive information on that issue, it would be appreciated.

>that may be balanced out by higher climate change impact when it's mined.

What do you mean by that? Natural gas is taken from oil wells, the exact same kind of holes in the ground that produce bunker fuel. It's the highest level on the refinery column.

Edit: Here is a picture of the gas market right now:https://en.wikipedia.org/wiki/Gas_flare#/media/File:Niger_De...

If LNG pans out we would move those fires into the engines of ships. It would probably be carbon-neutral up to the trucks that the pipe welders drove.

Re: Future sailors: what will ships look like in 30 years?

#50

Post by forapurpose »

whatshisface wrote: post #49
forapurpose wrote: post #39

Earlier quoted context omitted.

> LNG is definitely happening, and that alone will make a massive difference in emissions An important, if often repeated point: Natural gas reduces emissions at the point of consumption; that may be balanced out by higher climate change impact when it's mined. If someone has good, conclusive information on that issue, it would be appreciated.

> that may be balanced out by higher climate change impact when it's mined. What do you mean by that? Natural gas is taken from oil wells, the exact same kind of holes in the ground that produce bunker fuel. It's the highest level on the refinery column. Edit: Here is a picture of the gas market right now: https://en.wikipedia.org/wiki/Gas_flare#/media/File:Niger_De... If LNG pans out we would move those fires into t…

> Natural gas is taken from oil wells

There's a large boom, not new at this point, in extracting natural gas via fracking. My understanding is that the process produces emissions with high impact on climate change.

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