I do wonder whether it would make sense to put superthin solar cells (like there are in development) on the sails. Maybe with a sort of rig to rotate them upwards. That way one could use them combined with an electric motor for propulsion when there is no wind blowing.

Next - an oil supertanker powered by wind!

I would think that wing sails would be more efficient and better in bad conditions (they don't need to be trimmed). As in the land sailing record vehicle.

If they were to combine new electronic systems they could use turbines that drop into the water when going say 12-14 knots-lose two knots of speed but create enough power to then run for 6-8 hours at 6 knots for free basically.

Solar power is too expensive, too inefficient, and too delicate for a working cargo ship. I'd think you could more easily employ wave generators that harness the up/down motion of waves and convert them into linear propulsion.

I was about to say something similar to Skipjack. If they were to use the new flexible solar cells on those huge sails, it would soak up electricity while sailing and could charge batteries for electric motors when there wasn't sufficient wind. Then there'd be no need for burning even the waste oil (which of course, still pollutes the air and some ongoing costs for the shipping companies.)

Is the RR engine piston or Turbine?

Wind is great, sky sail great. rigid sails are great but large sails on large ships are a mistake. They simply do not produce enough power. They could also be very dangerous in high winds.

I think this is wonderful news. And it is wise that they do also carry an engine as hurricanes and large sailing vessels don't get along well at all. This way they are certain to be able to stay out of a storm's path. Six years ago a large sailing vessel and crew set out of Miami to avoid a hurricane while in port. Apparently sailing vessel at anchor, in port can rarely survive. All hands lost at sea and no trace of wreckage at all. Not even life preservers. Most people have no real clue as to what a hurricane in the tropics can be like. One rogue wave, immediately after the storm was observed to be 150 feet tall.

It would not be as efficient but some sturdy Savonius wind turbines could power a ship and charge batteries for when there is no wind. It wouldn't require any adjustments for wind direction. It is also possible to have an optional direct mechanical link to the screws to correct for some of the inefficiency.