Everything Old is new again - Flettner Rotor Ship is launched

The paper also projected a payback period of 8.8-14 years - but the lower end only comes into play if the ship does fewer voyages and therefore earns less money. The compelling case only applies to owner-operators, not to time or voyage charterers. I'd love to see Co2 emissions drop but the compelling case didn't apply to many operators.

 

This is

This is ac72 with multi element rigid wingsails


Look at that, flexible windgsails have better upwind traits than rigid wingsails and any current "performance boat" using common fabric sails look pretty lame compared, and still the myth of keeled sloop upwind fallacy is still there

 

Of course. Performance isn't the major benefit.
I started a thread on the topic The case for fully automated sailing rigs https://www.boatdesign.net/threads/the-case-for-fully-automated-sailing-rigs.69564/

The need for managing the equivalent of huge sail rigs using automated systems in complete safety is a big benefit.
Can you imagine having the three crew members of a 100,000 racing around the decks adjusting, trimming, optimising sails like the poor sods in "The Ocean Race" currently pounding their way across the Southern Ocean.
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But, as far as tested, documented performance, lets look at an actual comparison study .
https://www.tandfonline.com/doi/full/10.1080/17445302.2019.1612544#d1e628





Not so very different performance Polars comparing sophisticated sail systems with Rotors, and as noted in the Rotor description, the power required to turn the Rotors was included in the calculations.
PLUS
Vastly reduced Heel performance
The small space this technology requires on deck in comparison with the other two sail technologies
The ability to move the Rotors to help with Cargo operations

Between Safety, Ease of Handling, Comparative Performance the benefits of the Rotors stack up.

 

Already there are free-standing masts ignored by current sailboat designers and also lower and high aspect ratio sails also reduce heel

And small sailboats can transport cargo for free so no need for these behemoths that fuel consumerism

Today Im focusing in low height multi mast thin flexible wingsails acting as multi element wing and these are the present of safe engineless sailboats

 

No, not ignored. Uninsurable
Just been reading some posts on the Proa Forums, where they cannot get Insurance for unstayed masts.

Nice dream, but totally unrealistic. Until you can reduce civilisation to the stone age, you are looking at " 30 million twenty-foot equivalent units (TEU) of cargo are expected to be transported across the Pacific Ocean in 2024"

They must be magic masts, able to conjure up their own optimum winds. There is no such thing as a "safe engineless" yacht, especially one engaged in commercial operations.

 

Who cares about insurers? Already freestanding masts are safer, they bend and if they break is at the base just like laser masts and can be reinserted with few tools cutting the base from the rupture point


Rather 1950s-80s Consumerism is a nightmare and humanity has lasted millenniums without it, check your bias we can cut transportation by almost 99% just by growing local food, wood and textiles and closing landfills reusing everything

If you see ac72 catamaran wind polar diagram thats a safe engineless boat, besides a sail is a sort of wind engine blade


Check your bias

 

Historic details of the original Flettner Ships.

The first illustration is the before and After pictures of the first Rotor Ship, the Baden Baden




And her sister ship, who worked the Mediterranean for 6 years.



Courtesy of Professor Hubert Chanson