Hacker News Reader

Comment by nabla9 | Hacker News Reader

They work just like normal sails. A sail is just a wing sideways. It moves the ship by generating lift.

The ship moves forward when the angle of attack is adjusted correctly. See the picture: https://en.wikipedia.org/wiki/Point_of_sail#/media/File:Poin... The ship can't move directly against the wind, but it can close-haul 45 degrees against the wind assuming it has enough keel.

View on HN

> The ship can't move directly against the wind

Is that a fundamental physical limitation, or would it be possible to come up with a design that allows moving directly against the wind (while being fully wind-powered).

(EDIT: ok, answering my own question: I guess you could anchor the ship and use a wind-turbine to charge a battery, then use that energy to move a bit, anchor again and repeat)

Wind turbine ships can sail directly into the wind. There's no need to anchor or store energy — you can just power the propeller directly from the turbine.

Not sure about that. Normal sails "bend" away from the wind and thus have a much stronger lift. This concept's sails are "beant" outwards and would lose much of the wind's force. This source [1] states that "The futuristic sails are like airplane wigs using the same level of aerodynamic technology" which would imply that they absolutely do not "work just like normal sails".

[1] https://www.maritime-executive.com/article/swedish-collabora...

Wingsail works with the same principle as conventional sail, it's just more efficient (hang gliders use the sails to fly).

Wingsails like this generally have a 3x to 5x advantage in lift/drag ratio for equal area.

https://en.m.wikipedia.org/wiki/Airfoil

Reply on news.ycombinator.com