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Old 29-05-2007, 13:25   #1
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Some really basic sailing questions....

I have now been out on the water about 6 times so far this season. I am a total newbie when it comes to sailing but I have 2 questions, the first one is really messing me up from understanding theory and the second one is just from a lack of experience:

1) Apparent wind vs. true wind - One of the first things I figured out from reading/sailing is the various points of sail (beam reach, close hauled, etc). What I can't seem to understand is how do you determine what point of sail you're on: is it by the true wind (relative to say a flag on the shore) or relative to the apparent wind (what I see on the telltales).

2) The boats I have sailed all have a tiller. When I want to head up, I want I push the tiller towards the leeward side of the boat and the boat heads windward (opposite to the tiller). When you are sailing a boat with steering wheel instead of tiller, is the wheel "backwards" like a tiller where the rudder moves opposite to the steering wheel? So for example, when tacking do you still turn the wheel leeward?

I hope my questions are clear enough, but if not (or I've made a mistake) please let me know I'm sure for you guys these questions are easy

Thanks for helping out a newbie
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Old 29-05-2007, 13:54   #2
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Hi Merlin. When it come to sailing, We are all newbies, just at different points along the line of experiance.
Answer to No.1.
Apparent wind is where the wind is actually physicaly coming from.
Now lets sday, there is no wind. As you move forward, you feel a breeze upon your face, right? OK, this is called and "apparent" wind. It is not really there, it is something you area making by your forward motion. Now lets go back to sailing. So we have a wind we are sailing to. But because the boat is moving forward, it also produces it's own wind, just like when we moved forward and felt it on our face. This aparent wind has the affect of making the actual wind move slight forward in angle. How much it moves forward is determined by the speed we go foward in relation to the speed the actual wind is blowing. So a slow boat will have a slight forward increase in wind angle, a fast racing boat can have a very large increase in forward angle, because it travels so much faster. OK so far??
This translates into major importance only when heading close to the wind angle. Most boats can point 50 degrees into the wind when just starting to move. Give or take. As boat speed picks up, we can start to round up harder into the wind. Most boats can now point to about 30 deg into the wind Give or take. OK so far??
The telltales don't really tell you wind angle. You need a wind pointer at the top of the mast to give you this info. But the tell tales will tell you when the sail is unloading pointing to high, or has the right airflow. As the angle of the sail can always be trimmed, the telltales are telling you more about what is happening to the air over the sail. Even though the two are related, You don't really want to complicate boat heading to air flow over the sail by using the telltales to aid in pointing you. It only comlicates the issue and makes it less accurate. The result would be a sudden and dramatic unloading of the sail as the boat over points and the sail spills all the air.
Answer to No2.
A wheel is like steering a car. You turn it in the way you want to point the boat. A tiller is opposite.
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Old 29-05-2007, 14:11   #3
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Merlin, As to the beginner issue, boat goes out, boat comes back, you are a boater. Boat goes out, and comes back faster, you are a sailor. Boat goes out, weather gets nasty, boat comes back with all hands and not broken, you are a seasoned sailor. Boat goes out, and keeps on going, you are a cruiser.
We all asked those questions and many more. With each answer, the boat came back a little faster.
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Old 29-05-2007, 14:26   #4
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Quote:
Originally Posted by Kai Nui
Merlin, As to the beginner issue, boat goes out, boat comes back, you are a boater. Boat goes out, and comes back faster, you are a sailor. Boat goes out, weather gets nasty, boat comes back with all hands and not broken, you are a seasoned sailor. Boat goes out, and keeps on going, you are a cruiser.
We all asked those questions and many more. With each answer, the boat came back a little faster.

now THAT is an AWESOME definition! I love it. I'm up to seasoned sailor...now I merely gotta get to the cuiser part! LOL
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Old 29-05-2007, 14:38   #5
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Quote:
Originally Posted by Alan Wheeler
Hi Merlin. When it come to sailing, We are all newbies, just at different points along the line of experiance.
Answer to No.1.
Apparent wind is where the wind is actually physicaly coming from.
Now lets sday, there is no wind. As you move forward, you feel a breeze upon your face, right? OK, this is called and "apparent" wind. It is not really there, it is something you area making by your forward motion. Now lets go back to sailing. So we have a wind we are sailing to. But because the boat is moving forward, it also produces it's own wind, just like when we moved forward and felt it on our face. This aparent wind has the affect of making the actual wind move slight forward in angle. How much it moves forward is determined by the speed we go foward in relation to the speed the actual wind is blowing. So a slow boat will have a slight forward increase in wind angle, a fast racing boat can have a very large increase in forward angle, because it travels so much faster. OK so far??
This translates into major importance only when heading close to the wind angle. Most boats can point 50 degrees into the wind when just starting to move. Give or take. As boat speed picks up, we can start to round up harder into the wind. Most boats can now point to about 30 deg into the wind Give or take. OK so far??
The telltales don't really tell you wind angle. You need a wind pointer at the top of the mast to give you this info. But the tell tales will tell you when the sail is unloading pointing to high, or has the right airflow. As the angle of the sail can always be trimmed, the telltales are telling you more about what is happening to the air over the sail. Even though the two are related, You don't really want to complicate boat heading to air flow over the sail by using the telltales to aid in pointing you. It only comlicates the issue and makes it less accurate. The result would be a sudden and dramatic unloading of the sail as the boat over points and the sail spills all the air.
Ok I'm with you on the definitions of the apparent vs. true. The way one of my books explains it is when you are riding a bike:

If you are riding into the wind, the wind you feel on your face will be equal to a combination the velocity of the wind + the velocity of your travel

When heading downwind, no matter how fast you go you won't feel any apparent wind on your face.

I think I should have clarified on the telltales. The telltales I was referring to where those on the stays, on the windward side of the boat (so presumably NOT being affected by the sails).

In any event, I guess what I am trying to get at is let's say you have this picture below (courtesy of wikipedia)



Now in the image the boat is moving straight up. Relative to the true wind (#3) I woudl say this is about close hauled (~ 45 degrees to the true wind). But relative to the apparent wind it looks more like it's in between Beam and Broad reach (more than ~ 90 degrees to the apparent wind).

So the questions are

1) what do you call this? Close hauled or a Reach of some kind?
2) I think from your post, the telltales on the sails can only really tell you how the wind is affecting the sail. But can a telltale, on the windward side of the boat on the stay indicate the apparent wind?
3) Am I correct in saying you really can't tell the true wind without looking at a flag on shore or a windpointer (like you mentioned)


Quote:
Originally Posted by Alan Wheeler
Answer to No2.
A wheel is like steering a car. You turn it in the way you want to point the boat. A tiller is opposite.
Gotcha! When I'm heading say close hauled and I want to switch to the opposite tack (but still close hauled). I would:

In a boat with a tiller: hard a-lee, so push tiller towards the leeward side of the boat (or in other words towards the sail) which is going to cause me to head up

In a boat with a wheel: turn the wheel towards the windward side of the boat (or away from the sail) which will cause me to head up

Let me know if I didn't get it, but I think that makes sense!


Quote:
Originally Posted by Kai Nui
Merlin, As to the beginner issue, boat goes out, boat comes back, you are a boater. Boat goes out, and comes back faster, you are a sailor. Boat goes out, weather gets nasty, boat comes back with all hands and not broken, you are a seasoned sailor. Boat goes out, and keeps on going, you are a cruiser.
We all asked those questions and many more. With each answer, the boat came back a little faster.
I like that Working towards "sailor" right now

THANKS AGAIN!
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Old 29-05-2007, 17:45   #6
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Well, I'm gonna stick my 'thang' out there and say that I think Wheels has it backwards - I believe (and gawd help me if I'm wrong cause I KNOW I'll be corrected - ) that with an increase of boat speed, the APPARENT Wind moves FORWARD. In other words .. using the diagram above, switch 3 with 4 and reverse both arrow directions. If you look at the vectors you have the "Boat induced wind speed vector (item 2), and the True Wind Speed vector (currently 4 but should be labeled 3) resulting in the APPARENT Wind Speed Vector (currently labeled 3 but should be labeled 4).

Okay ... putting down the pointer and stepping away from the platform - hands raised and waiting for the shots across the bow.
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Old 29-05-2007, 17:56   #7
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Now in the image the boat is moving straight up. Relative to the true wind (#3) I woudl say this is about close hauled (~ 45 degrees to the true wind). But relative to the apparent wind it looks more like it's in between Beam and Broad reach (more than ~ 90 degrees to the apparent wind).


Looks to me like you might be reading the true wind vector incorrectly. The true wind is coming over the port quarter and the movement of the boat gives an apparent just forward of the beam. It's a beam reach.
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Old 29-05-2007, 18:09   #8
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Thomas,
The TRUE wind is where it's physically coming from.
You're exactly right.
Steve B.
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Old 29-05-2007, 20:37   #9
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It's All Relative To Your Speed (as Einstein would say)

Salient, you straightened out the diagram for me, too, when I was too hasty and assumed the lines represented oncoming wind. The diagram arrows clearly show the wind leaving the boat, so this craft is on a port tack (weather to port). In this case, the diagram correctly shows the affect of apparent wind: as the boat moves forward, the wind appears to be coming from a direction farther abow.

True wind: the direction the wind is actually blowing.
Apparent wind: the wind direction you experience as a combination (or ratio) of the true wind direction + the "wind" created by the forward motion of the boat.

As Einstein would do: a thought experiment:

Straddle a bicycle, and you may feel 10mph of wind coming at you from your right, or 90. Then pedal the bicycle at 10mph and you will create the feeling of a headwind coming at you from 0. What you experience with your senses is not two separate winds, but one wind, apparently coming at you from 45. The true wind is from 90 and never changes, but because of your forward motion, the wind is felt by you as coming from 45, and you will have to balance the bicycle accordingly.

The faster you ride, the more "headwind" you are creating as your speed dominates the ratio of head-to-side wind, and so the apparent wind (the combination of the two) seems to move forward: from 45 to 40, etc.

Imagine riding the bicycle so fast that 99% of what you feel is the wind pressure from your own forward motion and almost no pressure from the side: the true wind is still blowing 10mph from 90, but the apparent wind you are feeling is almost exactly on your nose.

Slow down, and the angle will appear to clock to the side again with every lost mph, until you come to a stop, when you feel only the side wind. The true wind never changed; but the apparent wind (the combination that you created by adding forward motion) changed with your speed.

Since you're not on a bicycle, but a sailboat, as your forward speed increases, the wind angle blowing over your boat will creep forward, though the true wind will not have changed. Sails must be trimmed accordingly.

That was a bit trickier to try to explain clearly than I thought it would be: how'd I do?

Merlin, are you still with us? We sometimes jump in and lose the original poster.
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Old 29-05-2007, 22:09   #10
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/\/\ thanks for all the help guys.

I fully understand the difference between apparent/true wind as you guys have explained it. It is very helpful

1) Now on the more "sailing speak" terms side of things. When people say "ok we're on a beam reach" or on we're sailing "close hauled" are they referring to the boat's point of sail relative to the true wind or apparent wind. I thought that image was helpful in showing that one could say you are on 2 different points of sail depending on which wind you are referring to so I guess it's a question of custom (or is it technical?!?)


2) Agreed that telltales on the windward side of the boat on the stays will show apparent wind, correct?
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Old 29-05-2007, 22:24   #11
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Merlin, When I purchaced my 34 foot Ketch I was handed down a book called Royce's sailing Illustrated (3nd addition) and explains many things about sailing
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Old 29-05-2007, 22:28   #12
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BTW - With the angle of the true vs. apparent wind in that diagram that boat is hauling a**.

1/ The point of sail is referenced the apparent wind and unless I am wrong has to do with the set of the sail rather than the direction of the wind.

Someone earlier said that when close hauled you can point higher as the boat accelerates? I find the opposite is true. As the boat accelerates the apparent wind moves forward and the sail luffs. I bear away and the boat slows a little. Eventually there is a balanced point of sail where the boat is at it's best speed and highest point.

Notwithstanding the efficiencies of different boats and that you may make better way on a lower popint of sail for a different boat.

2/ If the telltales are clearly out of the wind affected zone the telltales will show apparent wind. The telltales even on the windward side could be affected by the airflow over the sails depending on location. Better location for the windicator is top of the mast.

However when setting the sail efficiency the wind indicator is not as important as the telltales on the sails. They will tell you how the sail is doing.
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Old 29-05-2007, 22:53   #13
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Aloha Merlin,

Hope you aren't totally confused. What you sail by is apparent wind. While sailing true wind has little to do with what point of sail you are on. In a very fast cat the true wind could be on your starboard quarter but your point of sail might be close hauled starboard tack.

When you are on a beam reach starboard tack the wind (apparent) is coming directly over your starboard beam and your telltale on the starboard upper shroud should be pointing almost directly at the mast. It has little to do with where your sails are because you could have your sails adjusted improperly.

Your sails are only adjusted properly when they are not luffing but almost on the verge of luffing unless you are going downwind.

Look how much help you are getting from the guys just looking to give you a hand. Isn't this a great forum?

Kind Regards,
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Old 30-05-2007, 00:09   #14
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Capt America, Nice to see you on! WSvoboda there is the proud owner of the boat behind my signature line
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Old 30-05-2007, 01:28   #15
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Quote:
) that with an increase of boat speed, the APPARENT Wind moves FORWARD.
Thomas, as earlier stated, your exactly right. I thought that was what I said. Ummm, it was what I meant to say anyway.

The diagram is wrong/right. It depends on which way you interpret it. I think Salient is right. The wind is traveling in the direction of the arrows. The arrows are not pointing in the direction the wind is coming from. Us down here in the Southern Hemi would most likely have had the arrows pointing toward the boat :-)

Now for points of sail. Sailing terms came from the old tall ship days. Most terms used were of English origin, but it depends on how far back you go. Terms were easy back then. Sailors had a limited vocab and understanding of english and no mere deckhand could read or write. So terminology had to be simple. Many words were bastidised over the years and changed their sounding compleatly.
So to make it easy, you have several parts of the boat. Usually devided into "quaters"
Aft=stern or back of the boat.
Forward=Bow or front
Beam=Side.
Reach= was a "mark" or place you were trying to "reach" or get to.
So when you think about what you are doing with the boat, think about how one of the old timers would describe a way of getting the boat to go there with the wind trying to take him somewhere else.
There are some fantastic books available, but the best IMO is "The Boating Bible". I suggest you get it. It will answer all the above and much much more.
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