How a Boat Sails in Apparent Wind
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- เผยแพร่เมื่อ 15 ธ.ค. 2008
- Captain John with 25+ years of experience shows you the no-nonsense cruising skills you need for safer sailing worldwide. Visit his website at www.skippertips.com and sign up for his highly popular Sailing Tip of the Week. Discover how you can gain instant access to hundreds of sailing articles, videos, FREE e-Books and much more!
- แนวปฏิบัติและการใช้ชีวิต
Very simple explanation of a seemingly complex topic. Great video!
Thanks for your comment!
I've had so much trouble understanding this concept and you have explained it clearly and simply in a way I can understand. Thank you!
Glad to help!
I didn't expect to learn anything in this video. But, to my surprise, it clarified the important detail about how the sail actually works. Good job!
yep apparent wind or winds a definite must to learn about even on dry land.
Thanks for your note!
A superb video--simple and clear.
How many times have we heard this explanation just verbally without pictorial assistance??
These little diagrams with dynamic drawings really kill any confusion.
Well done Skipper!+
My brain has been refeshed.
Great channel..really great channel!
Thanks for your comments!
There's a fourth kind of wind. That's the wind that blows when your Captain is speaking! Actually, I enjoyed your presentation. I've been sailing for a long time, and I found your description of wind effect very knowledgable and helpful. Thanks.
Keep them coming and keep them short.
This video will totally changed my sailing habits. For whatever reason, I have always thought the main had to be perpendicular to the apparent wind (or as close as possible). What an eye opener. Oh, and I joined your SkipperTip site too. Thanks!
thx for the video this helped me a lot.
I am learning how to sail right now I got my first boat a few weeks ago after helping my dad sail his boat for 10 years I figured it was time to get my own so I got a 19 foot y flyer and fixed it up. its a fast boat!
'Similar' is an understatement. Wings and sails use exactly the same principals to generate lift. One just happens to be made from cloth...generally. Consider the solid 'wing sails' on the AC72s!
Love the videos. Thanks for making them and sharing them.
I finally get apparent wind in application, visually. Thank you!!!!
Glad it helped!
Salute to your teaching skills
Thanks for your note, Danny!
Great explination...Thanks for your help. Keep up the good work
Thank you Captain John
You're welcome, Dave. Thanks for your comment!
I have been researching designs for building a sailing rig for my kayak. also i need to learn some about sailing before i head out and your simple and to the point explanation here has helped allot. I will probably be sailing mostly rivers so a good understanding of how much into the wind and sail position for sailing into the wind will help allot. Thank you.
Thanks for your comments. Good luck with your kayak!
Great information.
Great video! You explain this very well. Thanks! 👍
Matthew, Glad it was helpful!
A superb video--simple and clear. SUB
Russ, thanks for your note!
Awesome, thanks!
Such a great explanation.
Thanks for your note!
Great vid
Good videos my friend ...
So trim the sails to apparent wind instead of true wind or boat wind. Got it. Thanks!
Todd, exactly. Have an excellent sailing season 2024!
@@skippertips thanks! You too!
When I am out sailing, I am always confused with where my masthead fly points - is the true wind before the fly or after the fly? I have a hard time figuring that one out.
Hello Sir,
I would be grateful if you could address the following questions:
1. If I wished to set sail in an African dhow (non-motorized) with a fixed lateen sail, in which direction should I point my sail for maximum speed, and in which direction should I point my sail for maximum stability?
2. Is it possible to sail faster than the true wind in such a crude sail-boat (7m in length) if I was to trim my single lateen sail close-haul?
Thanks
Somendra, on most sailboats, beam reaching will be fastest. I am not familiar with the dhow, but you might keep provisions in the center and low in the boat, the crew to windward, and reef the sail to increase stability. That applies to most boats. Ease the mainsheet if you need to spill more wind in in gusty conditions. On your second question, close hauled sailing is exciting, but not that fast. You are sailing more to the side than ahead (leeway). Reaches are always faster. You can sometimes sail faster than the wind when running (called "surfing").
Thank you!
hi captain I wonder what is the advantage of multiple sails in a boat (e,g. phinisi boat)? is it to avoid stalling better?
Glowie, sails are combined to balance the boat so that you do not have too much sail aft or forward at one time. One sail can increase the performance of another sail, so you sail faster. You also have the benefit of more sail area when reaching or running, which adds to your speed. Multiple sails give you options in different weather conditions. Split rigs, like ketches or yawls might sail with just a staysail and mizzen, or some other combo to keep the boat balanced and sailing fast.
Why is that when the apparent wind is parallel to the sail it reaches max lift? Is there still pressure difference on both sides of the sail (driving force)?
You build high pressure on the windward side and low pressure on the leeward side. The lift component on a sail is quite small. Keep your sails trimmed to maximize lift. This generates speed and your keel will provide a lot of lift to windward. Sailing is about getting all of your foils working in harmony. The result is a fast boat with less heel and weather helm.
Captain John's Skipper Tips
Captain John, I know the masthead fly shows the APPARENT wind. But where is the TRUE wind, when sailing, in relation to the masthead fly while moving? I assume that if the wind is forward the beam, it is in front (toward the nose) of the indication of the fly, but if the wind is behind you, then the true wind is aft of the direction of the fly. But I've never been sure, and I can't comprehend it in my head...
which boat is faster in lighter wind breeze downwind and up wind 5-8 knots, a cataraman or a monohull
I am not familiar with catamarans. Cats may sail faster downwind, but will often not be able to point as high upwind.
So... Is apparent wind what happens when true wind and boat wind interact?
Exactly. Apparent wind is a result of boat wind and true wind. Your boat sails in apparent wind. You trim your sails to the apparent wind. There are only two times in sailing when the apparent/true wind line up with one another.: when you are headed directly into the wind (i.e. to hoist or lower a sail or getting stuck 'in irons') and when running dead downwind.
Some wonderful videos but on this one there is a pretty significant inaccuracy. If you trim the mainsail so that is parallel to the wind , it will luff. The only way to get lift and to utilize the airfoil shape of the sail is to sheet it in a bit further than the angle of the apparent wind. That angle is called the "angle of attack" and how large or small it needs to be depends on wind speed and also the draft of your sail. At higher wind speed and smaller draft it needs to be smaller than vice versa. I hope that helps.
Thanks for your comments. Later videos address trimming the Genoa and the mainsail with telltales, or by easing the sail just enough to get it to begin to luff, then trimming in just enough to put the flutter "to sleep".
@@skippertips Thanks for your clarification.
what about angle of attack?
Leonardo, go here: Genoa Luff Telltales: th-cam.com/video/sW9lbZSAMrM/w-d-xo.html
I put a small flag on top on the mast so all i have to do is look up for TW .
1:41 in both of those examples the sail is parallel to the wind, so how the hell does the sail move the boat forward when it's directly against the wind? Why wouldn't you turn the sail anticlockwise a bit to tack, or whatever?
Never sailed in my life and I still don't see how you can physically sail into wind, at all.
Most of the flow over the sail creates side force when sailing to windward or on reaches. Lift to windward comes from the keel, which provides lateral (sideways) resistance. This results is forward motion. See this article: physicsbuzz.physicscentral.com/2015/05/the-physics-of-sailing-how-does.html
Oh ya ok ,so my boom should line up with the flag then ,thank you for that : )
? I do not get it at all
Dontrell, did you have a question on the apparent wind video?
As others have pointed out, if you were to line up your boom parallel with the apparent wind, the mainsail would just flog and provide only drag; I'm afraid this video should be disregarded by anyone learning to sail.
Richard, thanks for your comment.
you are talking about boat wind when motoring and you keep doing so , are you saying this demo is done with the motor running contantly because if the motor is off naturally the boat wind should not be there right. Thanks.
You produce boat wind if you are moving through the water by any means of propulsion. Boat wind is the result of boat speed. So, if your sails are up and you are generating just 1/10th of a knot of speed, you have boat wind. Same with an engine, oars, paddle, etc. Boat wind is simply produced by the forward motion of a boat moving through the water. Whether in a dead calm or raging storm.
Got cha that makes since, forgive me just learning this stuff.
No worries. Glad to help.
Why do you say to angle the boom parallel to the apparent wind. That's going to flap, collapse and generate no drive forces - only drag. Also, I thought your explanation of 'three winds' rather than 'components' could be a bit confusing to some.
Most of your other videos are truly wonderful. This one just felt a little poor.
GaryChap Gary, thanks for your comments. More accurate might be to state to trim the sail to the apparent wind.
lol .. man in all my years i never yet seen anyone who could teach how a one sails against the wind.. they ALways suppose the wind is in back pushing where ya wanna go.. well how about if where ya wanna go is straight against the wind?
It sounds like you are saying the sails work like a wing of an aircraft rather than being pushed along, (note: I'm a power guy not a sail one so on a learning curve even with 40 plus years on the water LOL)
Three types of wind? Too much, not enough and from the wrong direction. After watching this I feel a bit more edumacated.
Don, sounds like your list is why we sail, for the challenge. Of course, you could always get a powerboat and then your list might include 'location of the next fuel dock'.