[krasin]

I hope we get rid of cargo ships that burn matter. But sails are too high maintenance to be scalable.

Last year, as an experiment I've launched a tiny solar-powered boat ([1]). Ultimately, it was too small and underpowered only making ~900km ([2]) before dying.

I hope to build a bigger drone boat next, hopefully with an ability to move up to 1 tonne of cargo. Apparently, it's possible, but (unfortunately) requires very delicate engineering.

For bigger boats solar does not seem to scale. It appears that nuclear is the ultimate future for megaships.

1. https://imgur.com/a/eKlLCNg

2. https://storage.googleapis.com/samofly/track/index2.html

[jasonwatkinspdx]

This. Anachronism is not the answer. These newly built tall ships will never be anything more than in essence a vanity project for brands that want to highlight their environmentalism.

If you want an efficient modern cargo sail ship, you should start with freestanding self trimming wingsails. These have roughly 3x more lift vs drag at the same sail area. But far more importantly: they can be controlled entirely by deflecting a small control surface, similar to the rudder on an aircraft. This can be automated nearly trivially with commodity hydroelectric actuators, redundant electronics, etc.

Making those out of a sustainable material vs the common composites is an open project. But I strongly suspect even using modern materials, over the lifetime of the ship, such a ship would have better net carbon footprint than modern tall ships, if you're honest about the staggering amount of labor that goes into building and operating tall ships, and the footprint that has.

[hinkley]

We are going to have to think of a different way of accessing the cargo.

Cargo ships as currently built cede the entire middle section of the boat to cranes. Cranes they won't see until the end of their voyage, or the beginning of the next. The whole rest of the time you can't use the vertical axis for anything else.

Things that slide around tend to break loose in heavy weather, and boats don't stay afloat if the center of gravity moves too far, so sideways seems like a bad idea. I don't know what the solution is, exactly.

[jasonwatkinspdx]

Depends on the ship. Container ships are just one type. Bulk cargo and stuff like car transporters remain relevant too.

But in the case of container ships, they have frames every so often to stabilize and secure the load. Those are the natural tie in point for wing sails. This is a relatively straightforward naval engineering problem. CG vs Center of Lift has been well understood since the 1800s.

[nradov]

Fixed sails won't be viable for container and bulk cargo ships due to the need for unobstructed access. They might be able to make limited use of kite type sails for running downwind.

Sails could be more viable for tankers and car carriers. Those don't rely on cranes for loading and have more free space on deck.

[hinkley]

You could rotate it out of the way in port, assuming you can keep other ships from running into them (I've seen one fixed sale design that collapses like an antenna), but there are wear and tear problems with a mast that is not fixed, aren't there? Especially given the direction and magnitude of the forces we're talking about.

[jillesvangurp]

I have a few reservations about nuclear on ships:

1) Nuclear reactors produce waste that needs long term storage. There are lots of hypothetical / partial solutions for this and a lot of nuclear waste sitting there in temporary storage patiently awaiting the day that this problem is actually solved. Adding more waste to that pile is not a great idea.

2) Ships go to sea. The sea is treacherous. Meaning that waste might end up at the bottom of the sea when ships sink.

3) Seas have pirates. E.g. the coast of Somalia is a security risk. Pirates and nuclear reactors are not a great combination. Pirates with Muslim extremist backgrounds even less so. Basically, nuclear powered boats are dirty bombs waiting to get hijacked.

Burning fossil fuels is the problem that needs solving. However, burning synthetic fuels is perfectly fine and engines don't really care how the fuel is created. Synthetic fuels can be produced using clean energy and then pumped in large storage tanks on ships; very much like is the practice today with normal fuel. It's the obvious future. Hydrogen is an obvious candidate for this and there are multiple companies working on this and a few prototypes already sailing. Add some solar and wind to the mix and you get some efficiency gains. Other synthetic fuels are feasible as well. Even diesel could be synthesized eventually. The main challenge is building the infrastructure that is going to generate enough fuel at reasonable cost.

There are a few drone ship operators out there. They are not used for cargo and quite small but it works. These guys (https://www.saildrone.com/) use solar and wind powered autonomous drone ships for months long operations.

[nradov]

Nuclear may be part of our energy future, but security concerns and operating costs make it impractical to put reactors onboard civilian merchant ships. They can't afford to pay multiple armed security guards and trained reactor operators. Plus some countries don't even allow nuclear vessels into their ports.

A more realistic solution would be to use land based reactors to manufacture carbon neutral synthetic liquid hydrocarbon fuel. Then burn that fuel in the ships as an alternative to fossil fuels.

[TheSpiceIsLife]

I'd be interested to see the numbers on this.

How much diesel-equivalent fuel could a 1GW nuclear power plant create in one year?

Here's my back of the envelope attempt.

1000MW * 0.9 capacity factor = 900

900 * 24 * 365 = 7,884,000MW

7,884,000 * 0.3 = 2,365,200MW electricity to liquid fuel efficiency[1]

2,365,200MW * 1000 = 2,365,200,000kW

2,365,200,000 / 10 energy content of 1L of diesel being ~10kWh

236,520,000L of diesel per year from a 1GW power plant.

Australia alone uses something like 33,000 megalitres of fuel per year (that's not all diesel, a lot of it would be petrol, but close enough).[2]

So Australia alone would need something like 140 x 1GW nuclear-to-diesel plants.

Did I do something wrong here? That seems like a lot.

This[3] says Australia has electricity generating capacity was 66.5 gigawatts (2017 number), so my 140GW estimate to cover Australia's transportation fuel requirements by electricity-to-diesel seems within the correct order of magnitude.

1. Semi-educated guess from https://en.wikipedia.org/wiki/Power-to-gas#Efficiency

2. https://www.abs.gov.au/statistics/industry/tourism-and-trans...

3. https://www.world-nuclear.org/information-library/country-pr...

[elihu]

Rather than have one reactor per ship, perhaps you could have just a few ships with reactors? Regular electrically-powered ships would tether themselves to the reactor ship, and they'd cross the ocean in a large convoy. The tether would supply electrical power.

[nradov]

That wouldn't work in any sort of heavy weather. And very few ships follow the same route at the same time for convoys.

[shakna]

> But sails are too high maintenance to be scalable.

I'm not sure how true this is, as a number of sail-assisted designs are already in use around the world, and have been for at least a decade. There are even several insurance classifications for large-scale cargo ships that incorporate the various possible sail-assisted architectures.

[elihu]

I wonder if electric ships could be a reasonable option? I don't have enough of the relevant numbers to do the math on whether a modern cargo container ship with some fraction of its mass dedicated to (perhaps) lithium iron phosphate batteries at about 150 watt hours per kilogram would be able to go any reasonable distance.

If we assume for the sake of argument that it's not enough for most reasonable-length routes, maybe if there was charging infrastructure at regular intervals that would help? I'm imagining for example a ship crossing the Pacific from the U.S. to China, but stopping in at Hawaii, the Marshall islands, and the Phillipines to charge. Maybe not even in a port; maybe there'd be power lines that run out to buoys that have the maritime equivalent of a DC fast-charger.

Also, one could imagine overhead lines being installed over the Panama and Suez canals. Ships could reach up with pantographs and charge their batteries as the traverse the canal.

The extreme case would be to have power lines that stretch from one continent to another, and ships cross whole oceans without ever unplugging. I'm not sure how that would work, exactly: floating cables? Cables that run along the sea floor, but the ships run an extension cord that drapes down to meet it? Lots of mechanical problems that would have to be solved.

Even with charging infrastructure only available in some places, if ships were configured with diesel engines that can take over when the batteries are dead, running off of batteries at least part of the time could reduce the fuel consumption by quite a lot.

[patrickyeon]

That's really cool! It looks like you're in the SFBA (or at least launched your boat from nearby), so are you familiar with Sofar and Saildrone? Do you have a way for people to follow what you're doing, or pitch in? I'd be interested in this (contact info in my profile).

[krasin]

Thanks for the kind words!

Yes, I am in SFBA; I know about Saildrone; Sailbuoy, Liquid Robotics and a few other similar companies pursuing small data-collection drone boats. I didn't hear about Sofar yet - thanks for the link.

As a full disclosure, the boat I launched was made under collaboration with Blue Trail Engineering ([1]) known for SeaCharger ([2]). All cool parts on the photo are from them; my parts were camera / extra satellite modem / some cloud autopilot. I am way less cool than Damon from Blue Trail Engineering.

As for my solar drone boats hobby, it's so slow moving that there's nothing to follow at the moment. If I get the second boat out of the CAD stage, I would probably get something on my low-profile youtube channel ([3]). But I would not expect anything too soon: bigger boat requires very careful engineering, and with my limited hobby budget it will take time.

Anyway, thank you for the words of encouragement. :)

1. https://www.bluetrailengineering.com/ 2. http://www.seacharger.com/ 3. https://www.youtube.com/channel/UCXLwwf3muIhUs7zYIbRTHNw

[algo_trader]

Do one these things last in Ocean waters? Sharks? Hurricanes? Random accidents ? Petty vandalism and piracy?

Can you hit 10 year life time if you use commercial grade components?

[gabereiser]

Larger sailing vessels (10m+) are actually moving towards solar + hydroelectric with lithium batteries (48v) to power electric engines and generators. Sailing with wind power uses the hydroelectric generators and solar. Motor sailing uses solar and you regen a little bit from hydro or a wind turbine.

https://www.sailinguma.com/

[throw0101a]

Dan and Kika of Sailing Uma themselves recognize that this setup is not for everyone. Here's an interview with them on Sailing Ruby Rose on the subject:

* https://www.youtube.com/watch?v=xOAXi5huV1U

A better solution, for the time being, may be what Rebuilding Tally Ho is doing and use a hybrid engine:

* https://www.youtube.com/watch?v=xohxmwPfctg

He specifically chose a Beta Marine (marinized Kubota) diesel that has an electric motor/alternator connected to a 48V battery bank. If either the mechanics or electrics go, he can use the other. For short jaunts, like in and out of harbours, he can use the electric system to preserve fuel. The system has re-gen capabilities under sail.

More pricey though.

[gabereiser]

Awesome thanks for that! I wasn’t aware of Beta Marine’s hybrid engine. Looks awesome but definitely pricey.

[PaulDavisThe1st]

The article essentially dismisses lithium batteries as non-sustainable.

[coryrc]

Which is dumb, because the "saltwater" batteries have manganese cathode and titanium phosphate anode... doesn't sound radically different than lithium iron phosphate.

[cfn]

There were a number of fires in boats at the beginning of using lithium batteries that put off many people from using them.

[throw0101a]

Because "lithium" means a whole category of things. See this mega-thread that was started in 2011 when people will still feeling things out:

* https://www.cruisersforum.com/forums/f166/lifepo4-batteries-...

The chemistry of LiFePO4 was settled on (versus something that used cobalt, à la Boeing's 787), and the risk of fires has been reduced considerably. You're more likely to have a boat fire from bad DIY electrical cabling and a lack of fusing.

For more than you ever wanted to know about marine electrical/electronics see Jeff Cote's channel:

* https://www.youtube.com/user/pacificyachtsystems/videos

[gabereiser]

All batteries are non-sustainable. They burn out eventually.

[frankbreetz]

>I hope we get rid of cargo ships that burn matter.

What would be wrong with a hydrogen fuel ship or a biomass fueled ship?

[mapmap]

Very cool. How did you communicate with it? Or did you follow it in a larger boat?

[krasin]

Iridium RockBlock. Bandwidth costs were insane (~$1/KB).