Hundreds of years of innovation in water travel, and we come back to a sail. Granted, a metal one, but still a fucking sail.
There’s a reason they quit, though. It’s slow and doesn’t let you go in every direction. The midline area of earth has winds that move mostly towards west, while the north and south portions blow mostly east.
For those curious, these sails save 12 tons per day. The average cargo ship uses around 200,000 tons per day, so around 6% better fuel economy.
The 12 tons are a best case and they represent 37% of this ship’s fuel consumption, that would be ~32.5 tons a day, on average it saved 3.3 tons, ~10%.
Which makes the break-even point for such wingsails, which cost one hell of alot more than a few tonnes of fuel did … rather far-away/long-term, doesn’t it?
There was also a system using huge parachute-kite things, on carbon-nanotube-ropes, fired up into the sky with rocket-assist, and the things could apparently pull the ship, quite effectively…
… the service-subscription the ship was supposed to pay-for gave them the optimal route for fuel-savings vs time-to-get-there…
here, it was sorta like this, but the kite-sail looked different, and I’m pretty-sure they were saying something about nanotube cable for the kite, and it wasn’t just a concept, it was actually-working…
https://marinersgalaxy.com/giant-kite-pulls-ship-across-atlantic/
I seem to remember that at the beginning of covid, some shipping companies just shortened the bulbs on their hulls, to optimize for a slower cruising-speed, and saved money that way…
again, where’s the break-even on it
