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It’s honestly a shame that we didn’t keep pursuing sail technology. It’s great that we’re finally getting somewhere environmentally-friendly with ship tech nowadays as in the OP, but if we’d put the same amount of effort to innovate and advance sails like we did steam, I imagine we’d have pretty amazing (and completely green) methods of transport for all but the heaviest cargo loads (and even then, just split the load across multiple ships?).

Of course, nowadays the tech is probably so far behind that the cost of the necessary innovations to “catch up” sails to modern powering methods is completely prohibitive; I guess the environment will continue to take one for the team...

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> It’s honestly a shame that we didn’t keep pursuing sail technology.

We did, modern sail boats are much faster than they used to be and can almost sail against the wind (~30° from the wind direction). Fastest sail boats can cross the Atlantic in few days now. (speed record: 3days15h [1])

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

Isn't it purely for sport though ?

I think you're vastly underestimating how slow it is to ship things by sail. Take a look at some of the routes boats had to take to avoid the doldrums and find favorable winds: https://en.wikipedia.org/wiki/Winds_in_the_Age_of_Sail. Having to sail 2/3 of the way to America just to stay in good winds added 3 weeks to a month to every trip out of Spain or Portugal.

Take a look at the clipper route https://en.wikipedia.org/wiki/Clipper_route. To ship goods across the world by sail in any reasonable amount of time, you have to sail way down in the southern ocean, where the winds and seas are incredibly rough and dangerous, and many many people have died horribly. https://en.wikipedia.org/wiki/Roaring_Forties.

We stopped using sails, because people were tired of sailors taking one for the team.

You are correct for that time period and technology. Linen sails on square rigged vessels required directional winds towards your destination, as they were only efficient for downwind sailing.

Things have greatly improved with the wide adoption of the Bermuda Rig allowing you to efficiently set a course on all points of sail; https://en.wikipedia.org/wiki/Bermuda_rig

There's many challenges for sailing commercial freight but I don't think this would be as much of an issue these days.

Also note that many ships don't require speed.

Yes, your avocado's have to be delivered very time-sensitive. But coal, oil, soy and most other bulk not so much.

In fact, due to price-fluctuations, ships delivering bulk goods sometimes deliberately slow down their route (but I cannot find the incident where and when this was reported anymore)

Edit: three guys I know, operate a sail-powered cargo service [1]. Time is a factor, not because clients require speedy delivery, but because paying three sailors for 2 weeks on-board is more expensive than 3 days. They deliver e.g. chocolate from the west-indies to Amsterdam with their boat.

[1] https://fairtransport.eu/nl/tres-hombres/

I’m genuinely curious, what innovations could there possibly be for sails beyond increasing surface area or either the sails or the keel?

It is worth noting that rigging and sails for lightweight racing hulls has evolved way beyond anything that has ever been used commercially -- And would look quite weird (though still recognizable) to a 19th C sailor [0].

Also, the material science involved in creating laminated sailcloth is very close to state-of-the-art.

Of course, racing yachts go fast because they weigh very little.

Also, Kitesails [1] have been proposed many times over the last few decades, but I've not heard of anyone using one commercially.

[0] https://en.wikipedia.org/wiki/Wingsail

[1] https://cleantechnica.com/2018/09/11/airbus-seawing-kite-sai...

Skysails[1] sells them commercially. I cannot find how many ships operate those other than two "prototypes"[2]

[1] https://www.skysails-group.com/

[2] https://de.wikipedia.org/wiki/SkySails#Treibstoffeinsparung

They don't work like a traditional sail but "rotor sails" are a fairly recent innovation and seem interesting: https://en.wikipedia.org/wiki/Rotor_ship

I've seen articles here and there about adding them to tankers to increase fuel efficiency.

I can't imagine there would be that many.

Sails just don't provide all that much motive force, and they're far too unreliable (wind dies down, it doesn't matter how much sail you have.)

Maybe the GP was thinking more along the lines of general 'green' tech -- wind turbines, solar panels, etc? It would certainly be cool to see more of those to supplement existing propulsion systems on ships, and that would help reduce the amount of fuel burned for shipping, which uses some of the dirtiest fractions of petroleum.

Combining technologies would absolutely be a great way to pivot, as the article shows. Maybe it’s a dumb question, but why don’t we have sails on modern ships as a supplement?

I just lament that we basically completely abandoned such a great mechanism (sails) so haphazardly just because coal was cheap & reliable; now the environment pays the price.

Sails take quite a bit of space to store, they aren't exactly the lightest thing, and you need training and coordination of the sailors to deal with them. They also probably just dont provide enough benefit to offset the costs -- as I said before, sails don't actually provide that much force.

There are a lot of smaller boats that have both sail and mechanical engines, but that only works because they're small enough that the sails can provide a significant amount of force. And if you look at the transition period between the Age of Sail and Age of Steam, there were a lot of boats and ships that had both sail and steam engines. The sails were mainly relegated to backup, or to help out the steam engines, but these hybrids existed.

I just looked into the economics of rotor sails.

On average, they save $400/day ($146,000/year) in fuel costs (2017) or about ~10% of fuel consumption. In real terms, it's not much.

They cost about €1-2 mil ($1.1-2.3). Under the most ideal circumstances, that is a ~8 year payback, which is fairly long.

In order for the economics to work out, oil prices need to be higher and externalities (CO2 emissions) need to be included in the price.

We do. They just don't look like sails. This is a Maersk ship.

https://en.wikipedia.org/wiki/Rotor_ship#/media/File:Norsepo...

Low tech magazine has some practical examples of ships that operate sails in addition to fuel to lower fuel-usage: https://www.lowtechmagazine.com/2007/09/sailing-ship-re.html

At 10 mph wind, sails generate about 0.256 pounds of force per square foot (according to random website found via google). Therefore your several ton cargo ship gets next to nothing from sails.

We use the form factor quite differently. A game and watch is about the size of a cell phone these days.

As someone who was a racing dingy sailor in his youth, the answer is a gob smacklying lot of improvements have occurred in my lifetime, mostly this century.

Have a look at the America's cup races. Eg: https://www.youtube.com/watch?v=Y325JWyRslE

The first thing that hits you is the hull isn't in the water. The next thing is the sail boats in a modest breeze are giving the powered boats a run for their money speed wise. One thing that is not so obvious is the sails are now more aerofoils.

Back in the day, boats that had no hulls were a mad mans dream. Now we call them kite surfers. Some exotic ones have keel hanging from a bit of rope.

I’m no expert, but it’s possible that advances in material science, our understanding of wind & ocean currents, GPS, etc. over the last, what, 150 years? all could massively improve efficiency.

As far as I know, humanity was still improving sailing tech till the steam engine dominated it. I guess my point is that it’s impossible to tell where we could’ve been now without actually having those years of iteration & innovation; the steam engine quickly and abruptly stymied all developments on that front.

Only thing I could think of would be a hybrid boat...sail + solar powered / wind powered electric motor?

Off the top of my head:

- Motorised rotation of the sails to capture the wind.

- Automated tacking.

> It’s honestly a shame that we didn’t keep pursuing sail technology ...

You mean something like this? https://www.top-yachtdesign.com/oceanwings-by-vplp/

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