Point of Sail

[charliegrau]

This statement was posted in another forum to define Point of Sail.

"A point of sail is the relative angle between true wind direction and the vessel's course." Thus when a boat is sailing with true wind at 90 deg to it's centerline.. it is on a beam reach. This would be the point of sail whether the boat was limping along at 1kt or blasting along at 8kt.... no matter what the apparent wind indicator was showing... the boat is still beam reaching across the course.


I disagree with it, but wonder what other folks think. I have always considered points of sail to necessarily be expressed in relation to apparent wind.

 

[Kings Gambit]

Considering the discussion in the forum that spawned this one, I doubt we'll get very far here unless it can be agreed that one point of sail is "close-hauled" defined as sailing the boat as close to "the wind" as possible [without pinching or entering the so-called no-go zone]. And then, whether or not it is possible to be on two different points of sail at the same time.

I repeat an earlier example. If sailing close-hauled [and you can use true or apparent wind here], and the true wind gusts, the apparent wind will shift aft, which means the boat can come up. We call these lifts. So, at the moment of the lift the boat would no longer be sailing close-hauled [it would be close reaching] because it could with a change of heading come up to the new apparent wind [direction] until the gust passed.

However, the true wind DIRECTION DID NOT CHANGE; so before the gust the boat was sailing close-hauled; at the time of the gust the boat was not close-hauled b/c it could change its heading UP [relative to the true wind direction] and still sail properly. One constant true wind direction-- yet, the boat experiences two points of sail [close-hauled and close reaching]. SO--how can the Point of Sail be DEFINED by the true wind direction???

You have to use logic here!!

 

[Rob2435]

I was taught that it's the sails settings, not the wind direction. True you set the sails according to the wind, but if you use the sails to define your point of sail you don't have to think true or apparent wind.

 

[charliegrau]

The basic question is: In the Point of Sail diagrams attached, does the wind arrow indicate apparent or true wind?

 

[woodster]

The basic question is: In the Point of Sail diagrams attached, does the wind arrow indicate apparent or true wind?

correct me if i am wrong here the arrow shows true wind the direction you would point the bow in order to hoist the sail.....and going out on a limb here the wind in all those positions on your chart that make the boat move i would think that wind would be the apparent wind

 

[Kings Gambit]

The basic question is: In the Point of Sail diagrams attached, does the wind arrow indicate apparent or true wind?

It's always the apparent wind if sail trim is involved; BUT with the boat in irons at the top of the diagram the apparent wind direction=true wind direction. Once the boat gets moving and comes to its close-hauled course which you must trim to, the apparent wind does not equal the true wind direction. When the boat is running off, the apparent and true wind directions are once again aligned [more or less], etc., for "normal" boats. But, for ORACLE-- I don't think that was the case--hence the diversity of views on this topic.

 

[Jackdaw]

The basic question is: In the Point of Sail diagrams attached, does the wind arrow indicate apparent or true wind?

This is a STATIC picture designed to help teach a DYNAMIC concept to beginning sailors. All boats and sailors are different. If it matches well with your reality, call it whatever you want.

 

[Kings Gambit]

Yeah, the diagram becomes indecipherable in cases where a boat's course is 90 deg to the true wind direction and moving so fast that trimming to the apparent wind makes the boat's "point of sail" one of close reaching [on the apparent wind]. In these very fast boats, there may be no such thing as a "beam reach" unless the true wind direction is the reference--a point that Jackdaw made in the previous forum.

 

[Stu Jackson]

I was taught that it's the sails settings, not the wind direction. True you set the sails according to the wind, but if you use the sails to define your point of sail you don't have to think true or apparent wind.

This is a very interesting concept. And yet a THIRD point of view: i.e., true, apparent and this one.

I was incredulous when I first read this. I still am quite amazed. Regardless of wind speed or direction, are you saying that if you set your jib in tight and the mainsail is midship with the boom on the centerline that this means you are sailing closehauled?

Please help me understand this, 'cuz logic doesn't seem apply. Who taught you this doozy?

 

[charliegrau]

I think this is a simple diagram used to teach sailing vocabulary. The wind direction indicator is apparent wind, because it can then always be true. If your apparent wind is directly abeam you are on a beam reach, whether the true wind is forward or aft of the beam. The super fast boats like the America's cup boats are always sailing with the apparent wind forward of the beam. I would still consider their "point of sail" to be close reaching or close hauled, as opposed to the course which could be downwind. I read a blog from a crewmember that said the apparent wind on any point of the race course only varied by about 4 degrees! So Point of Sail discussions for these boats is pretty much moot. They trim the sails for the apparent wind, but they steer a course based their destination or mark, true wind, set and drift....at least that is the same as with our displacement boats. It is pretty wild to see a boat with sails trimmed in tight execute a jibe.

 

[markwbird]

Apparent wind is all that matters

The only thing that matters when setting the sails or talking about point of sail is apparent wind. The boat does not care what the true windis The only wind the sails see is the apparent wind.

 

[Joe]

This statement was posted in another forum to define Point of Sail.

"A point of sail is the relative angle between true wind direction and the vessel's course." Thus when a boat is sailing with true wind at 90 deg to it's centerline.. it is on a beam reach. This would be the point of sail whether the boat was limping along at 1kt or blasting along at 8kt.... no matter what the apparent wind indicator was showing... the boat is still beam reaching across the course.


I disagree with it, but wonder what other folks think. I have always considered points of sail to necessarily be expressed in relation to apparent wind.

I was taught that the wind direction depicted is TRUE. I've always accepted the definition of points of sail as the relationship between the boat's course and the true wind direction.

The diagram is used to teach beginning sailors the relationship between the wind direction and the boat position.

Using the Points of Sail diagram to understand where to position a vessel's sails , initially, is the most common application for beginning students.

At this point is where the controversy exists. Do we define the point of sail by our sail's position (apparent wind) or do we define it by our boat's position/course to the wind (true wind).

Since the Points of Sail diagram gives absolutely NO REFERENCE to BOAT SPEED and WIND SPEED(factors that affect apparent wind).... it stands to reason that they are talking about TRUE wind in this depiction.

I choose the true wind explanation. It makes more sense to me. It is far more practical and useful a tool when used in the true wind context. The apparent wind definition has little practical use except to say where the sails are... and you don't use them in sail trim commands... yet you do when you instruct the helmsman .... "head up to close hauled" or bear off on a run"

While getting your boat rigged, if you decide to sail across the lake to an anchorage due west and you see that the wind is coming from exactly due north.... What Point of Sail to you anticipate? Why, a beam reach of course..... That's why you decided to go to the anchorage and have lunch... it's an easy beam reach across the lake.

Once you're on your course due west, you note your boat speed increasing and pushing your wind vane forward a bit, so you trim in... same course, same point of sail. Then... you see a gust of wind on the water, you want to maintain the same course, and knowing that an increase in true wind speed will move the apparent wind aft, you ease out the sails to prevent the boat from heeling over or veering off course....still beam reaching.

The entire time... the wind stays out of the north, you are travelling west, you are still beam reaching.. yet your apparent wind indicator has been all over place.

That is the way points of sail was taught to me... It's a tactical or navigational tool when defined by true wind direction. It allows you do make decisions, it helps you determine you tacking angles. When defined by apparent wind direction it has little practical use.

Tacking angles, for instance. When closehauled you are talking about your BOAT'S angle to True wind direction, not the smallest number on my AW indicator, that device is affected by speed... What you really want to know is how close to the wind can my boat sail and make progress if speed is not the issue. You can determine your tacking angle by sailing close hauled on either tack... up to the point where the sails start luffing.... then...note your compass course. Now tack over to the other side and do the same thing. The difference between the two headings will be your tacking angle. It may vary somewhat depending on conditions... you should make a note of that. But the point is, once you know your boat's tacking angle you can plan when to turn for the layline, or to clear out of a crowded anchorage, whether you can turn to cross another boat's path if needed.

 

[25yearslater]

Good enough for me.

 

[Davidasailor26]

Something I don't get to say everyday, but I think I disagree with Joe on this one. Joe - you say that point of sail is a navigational tool, but I've only ever really thought about it as a sail trim tool. If I'm sailing on a close reach and the wind drops, I'll tell my crew that we're coming in to close hauled, and they'll know to bring everything in. If the winds increases, I'll say that we're goon more broad reach, and the sails go out.

Having said that, at the end of the day, the words are just words, and it really doesn't make any difference which way you define them if you're just thinking about what the point of sail a trip is going to be. If Joe is going to try to sail across a lake he thinks he'll be on a beam reach both ways. I'd look at the same lake and think "it'll be a close reach" or just "it'll be a reach", but we'd both make the correct navigational decisions based on the true wind angle, whatever we call it. I say I'd have an easier time telling my crew how to trim, but I'm sure Joe would manage that part too.

Polar diagrams that I've seen are usually drawn showing true wind angle, but they define specific numerical angles, not word defined points of sail, so the definition doesn't really make a difference to that.

 

[Rob2435]

First, I set the sails using true wind and trim(minor adjustments) to apparent. The only time apparent wind overtakes true is when the engine is on, with a few exceptions(NOTE: this is on my boat, not ORACLE).

Stu,

It's a matter of perspective. If the wind is over the beam and I pull my sails in, boom over centerline, jib on shrouds I would consider that my sails were close hauled with the wind over the beam, not that I was sailing on a beam reach(and don't flame me about why I would do this, it's just an example). I have always thought about it from the boat's perspective, as I can't change the direction of the wind, but I can change my boat's angle to the wind and/or my sail settings. Use whatever you like to enjoy your day of sailing...at least you're not at work!

 

[RichH]

The point of sail is always in reference to the TRUE wind.

Apparent wind is a 'relativistic' entity, dependent on the 'variables' of both wind speed and boat speed.
'Point of sail' is NOT dependent on relativistic 'variables'

The extreme example would be ultra-fast sailing deep downwind in a foiling catamaran or iceboat or super-fast planing sportboat... with the sails in the position of 'close hauled' while the boat is ........ broad reaching to the true wind', while essentially 'pointing or close reaching' into the apparent wind.

 

[Joe]

Something I don't get to say everyday, but I think I disagree with Joe on this one. Joe - you say that point of sail is a navigational tool, but I've only ever really thought about it as a sail trim tool. If I'm sailing on a close reach and the wind drops, I'll tell my crew that we're coming in to close hauled, and they'll know to bring everything in. If the winds increases, I'll say that we're goon more broad reach, and the sails go out.

.

You're not disagreeing with me.... you just learned it differently than I did. If it gets you around the course or off the lee shore...that's cool.

What is important to me is that you understand there is another way of looking at this... and that there are advantages to thinking of the point of sail as the boat's course related to true wind direction.... rather than just which direction your sails are pointed.

You use this info without knowing you do... when you decide to turn, for instance. You're not looking at the apparent wind indicator... I hope not, anyway. You're considering if you turn whether you'll be able to clear the end of the jetty perhaps... that decision is based on true wind direction. Because you know no matter what your AW indicator says... your boat can only sail about 45 degrees to the actual wind direction..... which defines the "close hauled" point of sail.

So... you need to understand that a point of sail is not JUST where the sails are oriented... it also means how the boat is related to the wind.. which can prove to be of far greater importance when making critical decisions.

 

[weinie]

The point of sail is always in reference to the TRUE wind.

Apparent wind is a 'relativistic' entity, dependent on the 'variables' of both wind speed and boat speed.
'Point of sail' is NOT dependent on relativistic 'variables'

The extreme example would be ultra-fast sailing deep downwind in a foiling catamaran or iceboat or super-fast planing sportboat... with the sails in the position of 'close hauled' while the boat is ........ broad reaching to the true wind', while essentially 'pointing or close reaching' into the apparent wind.

don't know if I like the word "relativistic". Relative in physics usually connotes two distinct "observers".

 

[charliegrau]

Very interesting discussion. If a boat can sail at 45deg angle to the wind, le'st say the true wind is coming from due north 000 deg...so if the boat is not moving but pointed at 315deg all is good. Close hauled in relation to the true wind. But...then the boat starts moving. What happens? Apparent wind moves forward, the sails begin to luff, so the boat has to fall off to maintain it's motion...it does not change the trim of the sails. But...it can no longer hold a heading of 315deg, and it can no longer sail at 45deg to true wind. So if the boat had to fall of 15deg and is now on a heading of 300 deg at a 60 deg angle to true wind. In planning the passage you would have account for that. If you counted on sailing within 45 deg of true wind, you would not be able to make your desired course.

 

[Jackdaw]

Very interesting discussion. If a boat can sail at 45deg angle to the wind, le'st say the true wind is coming from due north 000 deg...so if the boat is not moving but pointed at 315deg all is good. Close hauled in relation to the true wind. But...then the boat starts moving. What happens? Apparent wind moves forward, the sails begin to luff, so the boat has to fall off to maintain it's motion...it does not change the trim of the sails. But...it can no longer hold a heading of 315deg, and it can no longer sail at 45deg to true wind. So if the boat had to fall of 15deg and is now on a heading of 300 deg at a 60 deg angle to true wind. In planning the passage you would have account for that. If you counted on sailing within 45 deg of true wind, you would not be able to make your desired course.

You are totally forgetting that as the apparent wind speed builds, the true wind angle that the boat can sail in decreases. This is because the apparent wind moves AFT as it builds. While in light airs my boats sails optimally into the wind at 44 degrees true, in 15 knots it's optimal true wind angle is 36 degrees, and it can sail in 30.