this post was submitted on 19 Nov 2024
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xkcd

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The real key was inventing the windmill-powered winch.

https://explainxkcd.com/3013/

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[–] jpreston2005 22 points 1 week ago (19 children)

but how do you sail upwind?

[–] [email protected] 19 points 1 week ago* (last edited 1 week ago) (11 children)

Edit: I have been corrected. Please read the follow-up comments for better information. I'm leaving the original text below for context and transparency.


As I understand (I'll happily be corrected), the basic mechanism is that you want to align your ship diagonally off to the side, and the sails at a shallow angle so that the wind pushes you to the side (diagonally back and to the side, but the hydrodynamics of your bow resist the backwards component), so you gain some momentum. Then you turn into the wind to have that momentum carry you forward, sails parallel to the wind so it doesn't push you back as much. Turn off to the side again (either back to the same side, or continue your turn to the other side) and repeat.

It doesn't move you quickly, because it's rather inefficient in transferring the wind's power into opposite momentum, but it gets you moving at least a little.

[–] EvacuateSoul 6 points 1 week ago (1 children)

Not of the bow, but the center of all lateral resistance, which must be aft of the center of effort (sails). This includes the hull and rudder, but more important is the daggerboard/centerboard/keel, otherwise you would just be pushed downwind.

[–] [email protected] 2 points 1 week ago

Keel was the word I was thinking of, but couldn't remember. Thanks for the correction!

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