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Comment by burkaman | Hacker News Reader

The niche I'd like them to fill is low-carbon intercontinental travel. Right now the only option is hitching a ride on a cargo ship, which is very slow, expensive, and only low-carbon in a marginal sense, and the prospects for long-distance electric planes or actually-sustainable aviation fuel seem pretty grim.

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Believe me, low carbon intercontinental travel is ships. Like normal, mundane, boats.

Boats can lift so much more stuff for the weight of the craft and support that it is not even fair.

A container ship can lift about 10 times the weight of the ship as cargo.

I don't have stats for airships but my guess would be it is reversed, so no more than 10% of the weight of the airship in cargo.

Also, each airship can only lift very small amount of cargo so a single container ship can probably transport as much stuff as all the airships we will be ever able to build combined.

If you don't care about how much cargo is used, then you have sailing ships which we know quite a lot about. You can sail long distances without using a drop of fuel.

If you stick to container ships, you still have net zero options. We can use expensive hydrocarbon fuels made from renewable sources and drive those ships at slower speeds which would lower fuel consumption. This I think would still be so much cheaper than airships given the costs to produce and maintain those.

These airships are supposed to fill a niche halfway between ships and airplanes. Ships can take weeks to make a journey, planes take hours, airships can split the difference and take days. They're less efficient than ships but much more efficient than planes.

No need to convince me, I would love to take a ship instead of flying. I still think airships could fill a niche that waterships can't though, because again they're slow and obviously they can only dock on the coast. You can't take a boat from Chicago to Madrid. I think it would be fun to go train->boat->train, but that is a long journey.

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

Going to have to rebuild a sailing vessel fleet.

I would love that. The trip would take a few weeks though right?

> only low-carbon in a marginal sense

What's the issue with this? Cargo will always need to be shipped around so as long as the marginal impact is low that seems fine?

Cargo ships burn incredibly dirty fuel, the working conditions are bordering on modern slavery, and it isn't sure if some cargo travel routes will stay viable in the near future - the Panama Canal has issues fitting the latest and greatest ("Postpanamax") ships and it's dealing with severe water shortages, and the Suez Canal is under threat from Iran as well as from a repeat of the infamous Ever Given incident.

There are a lot of people working on converting cargo ships to ammonia fuel. This will at least burn clean producing only nitrogen and water with appropriate engine tech. The ammonia can come from green hydrogen, so it could be 100% clean tech and ammonia doesn't have the problem of needing to be compressed and has good energy density.[1]

[1] https://interestingengineering.com/transportation/worlds-fir...

The problem is, shipping is incredibly price sensitive (as evidenced by the industry's SOP of using cheap flag states, exploiting labor and burning bunker fuel aka refinery residue). As long as said refinery residue is cheap, they'll keep the old guzzlers for as long as they can, and only convert a couple "flagships" to ammonia to appease ESG investors.

It just doesn't scale, there's only a few passenger seats available, and if we used the whole cargo ship to transport people it wouldn't be low carbon anymore.

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