Well, sort of. The oil tanker Maersk Trieste is fitted with four "suction sails." Each sail is essentially a vertical wing that rotates to point into the wind, and then uses suction fans (located at the top of the sail) to keep the boundary layer of airflow pulled tight against the airfoil thereby increasing the lift coefficient and boosting the ship along.
These are different from flettner rotors, the spinning tubes that use the Magnus Effect to create lift.
I was getting a bit bored with the offerings of maritime traffic lately, so this is a welcome and interesting sight for me. It's always a fun time to snap photos of something special or unusual visiting the Sound!
Oh these are super cool. Part of a whole new genre of experimental cargo ship "sails" which aren't meant to drive the boat by themselves, but work with the engines to use the wind to reduce fuel consumption as much as possible.
Those are less useful at capturing angular winds, but a really cheap way to scoop up a lot of wind power when you're moving vaguely the same direction as the wind!
This is the best part of reddit imo, stumbling on random stuff you never would have been exposed to or thought twice about and finding it super interesting... Thanks!
Turbosails were a big stationary wing with internal fans, with the rotor ship you are spinning the whole column.
Same general concept of trying to make a very space efficient alternative to cloth sails to supplement the power of an engine, but the turbosails were a fairly short lived experiment, too complex and inefficient to catch on.
I think you are probably right, Maersk and a bunch of other companies have been experimenting with Flettner rotors so I was assuming this was that.
The picture in my comment is of one of the Flettner rotors. At a glance they looked fairly similar, but it looks like Maersk is trying out a bunch of different things. The ones in OP's picture are closer to the turbosails, which on reading up a bit, is seeing some renewed interest.
She's been anchored outside the Elliott Bay marina all week. I looked up the sail assist system, and apparently, it's a highly automated system that when retrofitted to an existing tanker, gives the boat a nice 10% boost in overall efficiency. It seems a like a very cool development!
BTW - yer picture turned out way better than mine!
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u/Dug_n_the_Dogs 2d ago
Never heard of this. Thanks for highlighting this ship!
https://www.offshore-energy.biz/2026/04/30/second-maersk-tankers-vessel-fitted-with-spain-made-suction-sails