lol, there actually was a few, but that is back in ye old days. 1968 - Otto Hans. 1972 - Mutsu. 1988 - Sevmorput (only one still running - but planned decomission is apparently in 2024)
Well, they still have a ton of greased up machinery below deck and they still need to properly store and dispose of bilgewater, so not perfect by any measure, but still way better than any other type of shipping.
I have an idea. I know it sounds far fetched, probably won't work but hear me out. What if they put large poles on ships and hung a big canvas from each of them? The wind could blow against these, generating free thrust and it can make the ships go faster. Wonder if anyone's ever tried that before.
But what about the oil companies who make massive profits selling the worst, bottom of the barrel, shit-tier bunker oil to cargo ship operators because regulations don't exist on international waters? Won't someone think of the oil companies?
There are actually a few cargo ships using Flettner Rotors. They can't completely power the ship - they require a bit of power themselves for the rotation - but they can noticeably offset fuel consumption.