If I go from Europe to Africa, I’m going south. But if air goes from Europe to Africa, it is called a north wind. Why is this?
My guess it has something to with the way weather vanes are/were constructed. Or perhaps where the wind is coming from is more important than where it is going to. But that’s about as much as I can figger without some extra help.
As a sailor, I need to know where the wind originates because it most definitely affects how I get where I want to go. It just makes sense to me for wind direction to be given that way.
As a fairy chat mom I would say it only makes sense to me to state where the wind (air) comes from. It affects me by its properties (cold/hot/dry/humid/dusty/etc) it got where it comes from. After it passes I have no idea nor do I care where it goes. For all I know it might turn right and enter a 7/11 for a snack.
FairyChatMom, if you want to go south, you want a wind which is blowing to the south, don’t you?
So wouldn’t it make sense to call that wind a “south” wind?
Why would you call it a “north” wind?
If you know where the wind comes from, you know which direction to look for oncoming weather, or where to search for the source of food being cooked, rotting carcasses that need to be buried or burned, etc. When using wind for power, unless you are in a hot air balloon, you do not need to know where the wind is going, because in any sail-driven vehicle (boat, iceboat, or–rare–wagon), you do not need to accept the wind’s direction, but can use its force, even at an angle to your desired direction, to go a different direction. On the other hand, you cannot sail directly into the wind, so you still need to know where it originated to set your sails to tack against it. With a North Wind, one can sail South or East or West. (Depending on the design, one can even sail a little bit to the Northeast or Northwest. Aside from unsteered ballons, no one is limited to going only in the direction that the wind is headed.)
There is one occasion where one speaks of the destination of the wind and not the source: when navigating near land, one speaks of offshore or onshore breezes to indicate that you will be dashed on the shore (onshore) or blown out to sea (offshore) if you fail to maintain control. Even in those cases, however, the compass direction is given according to the more useful source direction.
And just to confuse things a bit I will say that, while wind direction is given from where it blows from, current set (direction) is given in the direction where it goes to. A current which sets NW comes from the SE and goes to the NW. And current speed is called drift. I knew you’d want to know that.
Actually, the fastest point of sail, depending upon the boat, of course, is usually heading upwind, about 15-20 degrees off the wind. Running, or going in the same direction as the wind, is generally the slowest point of sail.
That’s because your sail is an airfoil - assuming you’re not flying a square rig. So you’re not being blown along.
>> Actually, the fastest point of sail, depending upon the boat, of course, is usually heading upwind, about 15-20 degrees off the wind
Is that so? I’d like to see it done. Can you tell me where I could see this? For me 45 degrees is a good beat.
This actually make sense in the same way that onshore and offshore make sense. Current is an obstacle or a threat to navigation, not the primary method of propulsion. (Certainly one can use it to aid propulsion, but it is still secondary to either the wind or machinery.)
I’m basing this on some articles I’ve read - high performance sailboats can really point up - I thought I remembered reading the 15-20 quote… I may be mistaken. I haven’t been able to find where I read that. Not that I know from experience - I sail a Fisher 37 motorsailer ketch.
Expanding on boat speed as a function of point of sail: This is a very tricky question because no two boats are alike and eeven every boat will have different speeds at different wind speeds but as a very general rule of thumb I would say in the great majority of cases a boat can reach its maximum speed through the water with the wind on the quarter, this is, sailing 45 degrees off dead downwind. Maximum boat speed is more constant for different points of sail with stronger winds while it changes more and increases when the wind direction shifts to the beam with weaker breezes. For any constant given true windspeed I doubt there is any boat which can move faster thorugh the water when beating than when on a broad reach. If there is such a case I’d like to see it.
OOps, I really am screwing up today. I forgot a link to a page with a polar diagram showing boat speed as a function of point of sail. http://www.sailnet.com/collections/articles/index.cfm?articleid=carrmi0024 This is a pretty typical polar diagram.
Not just for boats… planes take off and land into the wind, thus knowing which way the wind is coming from is more important than where it’s going. You know which runway to select and how much of a crosswind to counteract. Even landing with a 5-knot tailwind can make your day interesting.
Well, it all goes to show that as a cruiser, I have no idea what I’m talking about when it comes to performance sailing, and I obviously misunderstood or I believed one too many sea stories. Be that as it may, ya still gotta know where the wind is coming from to figure out how to get where you’re going. Which was going to be my point in the first place.
The one thing you can sense about wind is which direction it comes from. Standing there getting hit by it, you KNOW whence it comes. You do not KNOW where it’s going, or even if it’s going anywhere, from your senses. Thus, I would imagine that even before humans had speech they perceived wind as coming FROM somewhere. Old habits die hard.
When you head off on a journey, the primary aspect is where you’re going to. Someone you bump into on your trip will talk about your coming from the North, but you will talk about your heading South. It’s a matter of point of view.