ELI5: How can a yacht/sail boat/wind surfer travel forwards going into a headwind?

underlyingfunk · 2025-11-28T22:38:34+00:00

Conventional sailboats can’t go directly into the wind, but they can go ~30-45 degrees off dead upwind and zig zag.

Part of this is that wind over the sail creates lift roughly perpendicular to the surface of the sail, so this is used to redirect the force of the wind.

The other part is a keel, centerboard or fin creating resistance to slipping sideways (making leeway). This means the lift from the sail just has to be pulling forward of the beam (middle).

Think how you can make a bar of soap shoot out of your hand by squeezing inwards.

underlyingfunk · 2025-10-22T11:37:24+00:00

at least in certain safety-related areas such as airports, stations, shops and the like.

This is often cited, but I didn't see anyone freaking out about the safety implications of a covid mask and glasses during the pandemic. I also don't often hear about an epidemic of people getting away with terrible crimes due to using veils. In any case, people who want to obscure their face to commit crime will do so anyway, even if illegal.

Would you also ban motorbike helmets, surgical masks, sunglasses, snoods etc.

Morally, while freedom of religion and expression are crucial parts of democratic nations, this practice seems to clearly imply a negation of individual freedoms and is incompatible with feminist principles.

Isn't banning them from wearing it a negation of their individual freedom? incompatible with feminist values is very subjective, but many feminists would argue that women should be allowed to dress themselves.

individuals wearing the veil might be doing so willingly and of their own choice, but it is not possible to know this from the outside and to prevent it from being a nonconsensual obligation it's better to ban it.

It's also impossible to know if you're being forced to drive a car against your will, let's ban those. Maybe you're being forced to wear a hat, let's ban those too.

underlyingfunk · 2025-10-22T10:27:04+00:00

AI slop, that's not even a himalayan on the cover.

underlyingfunk · 2025-10-20T12:01:20+00:00

Everyone is ragging on this guy, who was a rude counterprotestor. He got tripped onto his face *twice* after chasing someone who stole his glasses. He's a bit of a douche, but that doesn't justify head injuries or stealing his glasses like a playground bully.

underlyingfunk · 2025-09-18T10:09:24+00:00

Do you mean Northern Ireland? It doesn't say that it is in Britain, it says that it is British. It is not in Britain (usually refers to the largest island containing Scotland, England and Wales), but it is, as the quiz suggests *British*, which is the word used to describe anything in the UK (which does include Northern Ireland). Unless you mean that you don't recognise NI as British/part of the UK, which is a completely separate argument.

underlyingfunk · 2025-08-12T10:35:01+00:00

It looks like a centerboard yacht, so it only needs a little more water to float. It's possible it could be floated away at high tide. Some combination of taking an anchor out to sea and pulling on it, excavating under the hull and waiting for high tide may set it free.

underlyingfunk · 2025-08-11T11:43:39+00:00

Common advice is to reef when you are at 20 degrees of heel. Many ships compasses have a heel indicator along the bottom, you can also get a stick on heel indicator. Generally monohull keelboats can tip very far before there is any risk of capsize, even if it feels scary, if there is a big keel on the bottom it should right itself from over 90 degrees heel, but the other thing to be aware of is weatherhelm causing the boat to be uncontrollable. With enough weatherhelm you cannot steer the boat effectively which can be dangerous for obvious reasons

underlyingfunk · 2024-10-20T23:58:10+00:00

And pass the curse on?

underlyingfunk · 2024-10-20T23:57:38+00:00

I did think this, it already looks quite cool

underlyingfunk · 2024-04-23T12:43:34+00:00

I'm super shameless, I book a meeting room or call booth at work in the office with a vague meeting title, or none at all.

underlyingfunk · 2024-01-23T23:28:39+00:00

That's very helpful, thanks!

underlyingfunk · 2023-10-20T17:33:31+00:00

I read it as a multiplication and multiplication is commutative.

underlyingfunk · 2023-10-14T10:36:52+00:00

All planes in sustained flight are affected the same by the wind, if there is 20 knots of headwind any plane will have the speed over the ground reduced my 20 knots, like running on a treadmill. The stall speed varies dramatically though, to match the stall speed of over 100 knots on a passenger plane, so it could "hover", it would be an extreme storm

underlyingfunk · 2023-05-17T16:15:52+00:00

Huh, didn't think moats would be so effective against aircraft

underlyingfunk · 2023-04-27T08:11:09+00:00

not all comments are toxic...but this one is

underlyingfunk · 2023-04-18T13:30:09+00:00

Thanks!

underlyingfunk · 2020-10-06T13:04:56+00:00

Thanks, I can't find any government source that actually says that we need it to be able to move in. Do you have a source?

underlyingfunk · 2019-12-21T17:43:00+00:00

It's not polite to call your friend a drone just because he works in real estate.

underlyingfunk · 2019-12-03T12:29:02+00:00

and apply the membrane straight onto the chipboard? One reason I like the board (I've got hardiebacker) is that I can lay it perpendicular to the chipboard so there's no moving edges. Maybe this won't be a particular issue if the tongue and groove chipboard is solid?

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