Agree that it's not going to be a binary shift. The tech does look promising for at least rotor sails, but that's an improvement which also demands use of traditional powerplants to drive the rotors ofc. Still worth investigating imo considering the shipping industry is the area of the world that still contributes highest to carbon output and is sort of an "untouchable" industry due to criticality. If cheap enough this could help while we wait for e.g. "greener" fuel or other things to develop. But yeah, to underscore further, not like shipping will look like my sailing yacht any time soon.

If you had bothered to at least skim TFA, this is addressed in the third paragraph:

> The idea is not to turn modern cargo ships back into sailing vessels. Instead, these systems are designed to work alongside conventional engines, using the wind to reduce fuel consumption whenever conditions allow.

Longer term I think we'll also use synthetic liquid hydrocarbon fuels manufactured through the Fischer–Tropsch process. People have proposed bringing back nuclear powered merchant ships but that's a non-starter for cost and security reasons. We can keep the nuclear plants safely on land and use them to make carbon-neutral fuel.

I think it’s clear that they are not turning back to use them exclusively, but clearly are ‘turning back’ in an additive way.

Eg putting these things on ammonia powered vessel will reduce the amount of fuel needed, which is probably a net benefit.

We're not going "back" to wind, but there are vessels with modern sails already deployed to save a couple of % fuel costs. There were 9 in 2020 and are 64 now, according to Sintef. Of course kinks are still getting ironed out, but it seems likely it will continue to grow.

Couldn't they use sails plus that? Are these companies advocating for just sails, or sails plus other stuff?

And yet:

  Klaveness Combination Carriers (KCC) has launched a brand-new vessel that aims to use wind technology that the company believes will not just reduce emissions, but also improve fuel efficiency on its voyages between China and Australia.

  Equipped with the first wind-assisted propulsion system in KCC’s fleet and a range of advanced energy efficiency technologies, MV Baltazar was officially launched at Fremantle Port this week

  .. According to the company, due to the ship’s trading area, size and advanced energy efficiency measures including suction sails, MV Baltazar has the lowest carbon footprint of any vessel in these trades.

> de-carbonizing shipping either with ammonia combustion, fuel cells, or both.

Or methanol:

  Methanol is emerging as one of the most practical low-greenhouse gas (GHG) fuels for deep-sea shipping.

* https://www.dnv.com/maritime/publications/methanol-fuel-in-s...

* https://www.lr.org/en/knowledge/research/fuel-for-thought/me...

How about the equivalent of an space elevator turned 90°:

Can we built giant conveyer belts across the ocean?

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