Ocean Conservation & Tidalpunk

This is really cool! It sounds like it's operating a bit like the Grain De Sail II carrying high value cargoes (campaign and cognac) which probably offset the somewhat higher operating costs. The Grain De Sail at least was transporting French wines to the US on one leg of the journey and raw coffee and cocoa for processing in Europe on the way back (I think another article was claiming they were planning to transfer aid supplies from the US to ports south on some runs but this article doesn't mention it).

It seems like sail ships might still be viable for some of what they were traditionally used for - luxury goods and necessities that could only be acquired elsewhere. Container ships made it profitable to ship everything and more and more I'm wondering if that's part of the problem.

Also I love all the upgrades and improvements they've made to sail ship designs for safety and to reduce the number of crew they need. These things are exactly the kind of anachronisms I feel like we'd see a lot of in a solarpunk world.

As a result, I guess that rotating masts aren’t optimal after all - too much moving mass, impossible to take down during a hurricane, etc.

Rotating masts are for ships that are larger, and they only contribute to propulsion, saving up to 30% of fuel. But they work well in almost any wind direction.
This ship is primarily driven by the sails, if conditions are good.
It's different technology for different tasks.

I also guess that this sailboat has a fairly good motor, for use during total lack of wind (rare) or storms that would damage sails or masts.

It has a 5500 horsepower Diesel-eletric motor. "For maneuvering in harbor and punctuality of service" according to the manufacturer.