Wind speed/direction gauges...do you use them?
- Thread starter kito
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wind instruments
I don`t own any I use a couple of homemade tell tales for wind direction as far as wind speed, after 50 years I can pretty much tell velocity by looking at the water I do own an old hand held anemometer but I don`t use it much.
I don`t own any I use a couple of homemade tell tales for wind direction as far as wind speed, after 50 years I can pretty much tell velocity by looking at the water I do own an old hand held anemometer but I don`t use it much.
I had a full suite of wind instruments on my 356. It was nice but the true wind function doesn't work if the speed paddlewheel doesn't work. Since it would foul with growth often, and more often wasn't accurate, the true wind function was often not working or inaccurate. And, you can re-calibrate the boat speed (Through the water) and thereby change the true wind direction. I haven't done the math and maybe there's not so much difference between 5 and 6 knots; but it is a bit arbitrary. So it already doesn't mean that much over feeling the wind on your face.
I like Joe's method but I'm not particularly good at arithmetic.
I like Joe's method but I'm not particularly good at arithmetic.
If your old Wind S & D transducer at mast top is working, you can reconnect the wires where they arer cut. Do you have easy access to the cable end where they are cut? There are 4 insulated wires and a shield Drain. The Red and Shield Drain provide 12Vdc power to the masthead unit The Speed signal is read between the Shield Drain (Common) and Yellow. The Drain and Blue give the Cosine of the wind direction , and the Drain and Green give the Sine of the Wind Direction (the Wind Instrument knows what t do with these signals. You can either butt-splice wire to wire of the same color (or Drain), or, if inside in a dry location, you can run the cables into a "project box" (@ Radio Shack) ad connect them to a Euro Terminal Strip. When connected, if bars wire or terminals are accessable you can measure voltages to see if all is working. The voltage measurements would be :
Drain to Red: about 8 to 9Vdc
Drain to Yellow: Half of the above ( 4 to 4.5 Vdc) since it is a Square wave af variable frequency.
Drain to Blue and Drain to Green: about 2 to 6 Vdc. (But not the same for both)
If you want you can always get a new Raymarine i60 Wind Instrument/Display and use the old Mind Mast Top unit. It works fine. If you connect i60 Wind to an i59 Tridata Instrument with the supplied SeaTalk NG Cable, the i60 Wind receives boat speed thur SeaTalk cable and calculates True Wind, So, you can see either Apparent or True Wind. I just went thru replacing both the Wind and Tridata Instruments in the cockpit and used all of the old Transducers.
Drain to Red: about 8 to 9Vdc
Drain to Yellow: Half of the above ( 4 to 4.5 Vdc) since it is a Square wave af variable frequency.
Drain to Blue and Drain to Green: about 2 to 6 Vdc. (But not the same for both)
If you want you can always get a new Raymarine i60 Wind Instrument/Display and use the old Mind Mast Top unit. It works fine. If you connect i60 Wind to an i59 Tridata Instrument with the supplied SeaTalk NG Cable, the i60 Wind receives boat speed thur SeaTalk cable and calculates True Wind, So, you can see either Apparent or True Wind. I just went thru replacing both the Wind and Tridata Instruments in the cockpit and used all of the old Transducers.
As it has been pointed out several times [to Joe], the true wind direction and one's point of sail have next to nothing to do with each other. Point of sail (e.g., closed-hauled) is relative to the apparent wind; so you're not likely going to ascertain TRUE wind direction by averaging [uncorrected?] compass headings which are themselves defined by the apparent wind direction [when close-hauled, in this case].
It's not entirely precise to say that the true wind angle and point of sail have nothing to do with each other. The apparent wind angle (and therefore point of sail) is a function of true wind angle, true wind speed, and boat speed. Therefore, assuming the same boat speed and wind speed, sailing close hauled on each tack will mean that you're sailing the same true wind angle on both tacks. While it's impossible to determine what that true wind angle is just using one tack, looking at compass angles on both tacks and averaging does allow you to determine true wind direction. It will be less effective in gusty or shifting winds.
The point of sail is ALL about True wind direction. Your mistake is confusing the apparent wind gauge's face with the point of sail diagram. They look similar in that they both relate to the boat's centerline...but they are different data sets.
The point of sail describes aboat's position relative to the wind across the water. Were as the apparent wind indicator, with its mirrored sides, O at the top, 180 at the bottom... shows the direction and speed of the wind as it is sensed when passing over the moving boat, striking the sails.
This is why we use a point of sail to initially set our sails....but as the boat starts moving we use the apparent wind info to fine tune our trim for maximizing performance.
Except going straight upwind or dead downwind... the apparent wind indicator will always point forward of the true wind direction.
Again the confusion lies with the similarity between the common points of sail chart and the dial face of the apparent wind indicator.
I stand by my statement that averaging the boat's compass headings on both close hauled tacks will give you a true wind direction.... ex. Starboard tack 90, port tack 180... true wind 135..... the apparent wind indicator is not needed... why, because true wind is defined in compass points or degrees. If expressed relative to the boat's course. 45 deg true, it defines the point of sail.... but that number is determined by comparing compass course and true wind direction. If say 45 deg apparent, that number is determined by relating wind direction to the moving boat's centerline, or how it's hitting the sail's.
This is one reason some sailors over estimate their boat's pointing ability, they watch the apparent wind indicator and see it at 40, so they think "that's 80 deg tack to tack.. and they misjudge the lay line. Your apparent wind indicator is good for trimming sails, tell tales are way better... they show apparent wind as it directly affects the sails. But you need true wind dir and speed to determine your boat's tacking angles... You take notes when sailing under various conditions external to the boat... then place reference lines on the boat, or construct a tack angle chart with sets of relative bearings for various conditions.
The point of sail can be changed by altering a vessel's direction (heading) or a shift in true wind direction.
A point of sail cannot be changed by boat speed or true wind speed. Apparent wind direction can be changed with these variables.
The point of sail describes aboat's position relative to the wind across the water. Were as the apparent wind indicator, with its mirrored sides, O at the top, 180 at the bottom... shows the direction and speed of the wind as it is sensed when passing over the moving boat, striking the sails.
This is why we use a point of sail to initially set our sails....but as the boat starts moving we use the apparent wind info to fine tune our trim for maximizing performance.
Except going straight upwind or dead downwind... the apparent wind indicator will always point forward of the true wind direction.
Again the confusion lies with the similarity between the common points of sail chart and the dial face of the apparent wind indicator.
I stand by my statement that averaging the boat's compass headings on both close hauled tacks will give you a true wind direction.... ex. Starboard tack 90, port tack 180... true wind 135..... the apparent wind indicator is not needed... why, because true wind is defined in compass points or degrees. If expressed relative to the boat's course. 45 deg true, it defines the point of sail.... but that number is determined by comparing compass course and true wind direction. If say 45 deg apparent, that number is determined by relating wind direction to the moving boat's centerline, or how it's hitting the sail's.
This is one reason some sailors over estimate their boat's pointing ability, they watch the apparent wind indicator and see it at 40, so they think "that's 80 deg tack to tack.. and they misjudge the lay line. Your apparent wind indicator is good for trimming sails, tell tales are way better... they show apparent wind as it directly affects the sails. But you need true wind dir and speed to determine your boat's tacking angles... You take notes when sailing under various conditions external to the boat... then place reference lines on the boat, or construct a tack angle chart with sets of relative bearings for various conditions.
The point of sail can be changed by altering a vessel's direction (heading) or a shift in true wind direction.
A point of sail cannot be changed by boat speed or true wind speed. Apparent wind direction can be changed with these variables.
Basically, you've got it... although you should never confuse apparent wind angle with point of sail. A very slow moving boat will have similar true and apparent wind data. But faster sailboats... racing dinghies, multi hulls etc... will have vastly different values because of their higher speeds. Actually, in gusty, shifty conditions... noting the close hauled headings as you tack upwind, will give you super data on changes in the true wind direction and velocity. Tactical electronic compasses do this exact thing. They memorize previous headings to indicate wind shifts, and those are true wind shifts, not apparent.
The easiest way... is to add 360 to the equation. Add and divide by 2.... if the answer is over 360, you would subtract out the 360.
EX: stb = 280 prt 10 280+10+360= 650 / 2 = 325
stb = 350 prt 80 350+80+360= 790/2 = 395 or 35 (395-360)
Or you could figure the difference between the two just by looking at the compass card... and split the difference.
I am going to show my ignorance here so near with me as I am not well versed in this. I'll be expecting corrections to anything I say.
It seems to me any tell tails on the boat whether it be a hand held wind meter, the little tails on the shrouds or a windex are going to give you apparent wind unless you are anchored and not moving.
My limited experience tells me some more about where the indicator is. For instance, I have noticed more often than not my shroud indicators will point differently when they are on the windward side than on the leeward side. The windward side seems a little more accurate but it's subject to eddie's (may not be the right term) from the main, the leeward is affected by the wind coming off the jib and the slot. The masthead is usually more correct but can be impacted by heel angle. The wind 30' up may be different than the wind at the water because of turbulence by the waves.
As for finding true wind direction, it seems to me close hauled assuming same heel and speed in both tacks is about as accurate as any as long as you are not dealing with any water currents. Seems to me pointless to worry about that unless you are in a race or are otherwise in a hurry or have along way to go with a short time to get there.
For me? We usually have no where in particular to go, so we just sail for the fun of it but we don't often have a destination. (Other than returning to the marina when we are ready to go back). That said, what's not important to me may be greatly important to someone else. I get that.
Oh, knowing wind direction and trimming the sails is important, don't get me wrong. You don't have any control over the wind speed or direction. You'll have to adjust for puffs and gusts and should be watching for those on the water. Short of radar and weather reports and watching where you should think about reefing or finding a safe place if it's going to get bad, you adjust and trim as a reaction to what's here and now.
Non sailers don't get how you can sail into the wind and to a point you can't (directly). Their concept is limited. As sailors, we harness the wind to allow us around 280-300 degrees of angle and we use tacking to fill in the rest.
It seems to me any tell tails on the boat whether it be a hand held wind meter, the little tails on the shrouds or a windex are going to give you apparent wind unless you are anchored and not moving.
My limited experience tells me some more about where the indicator is. For instance, I have noticed more often than not my shroud indicators will point differently when they are on the windward side than on the leeward side. The windward side seems a little more accurate but it's subject to eddie's (may not be the right term) from the main, the leeward is affected by the wind coming off the jib and the slot. The masthead is usually more correct but can be impacted by heel angle. The wind 30' up may be different than the wind at the water because of turbulence by the waves.
As for finding true wind direction, it seems to me close hauled assuming same heel and speed in both tacks is about as accurate as any as long as you are not dealing with any water currents. Seems to me pointless to worry about that unless you are in a race or are otherwise in a hurry or have along way to go with a short time to get there.
For me? We usually have no where in particular to go, so we just sail for the fun of it but we don't often have a destination. (Other than returning to the marina when we are ready to go back). That said, what's not important to me may be greatly important to someone else. I get that.
Oh, knowing wind direction and trimming the sails is important, don't get me wrong. You don't have any control over the wind speed or direction. You'll have to adjust for puffs and gusts and should be watching for those on the water. Short of radar and weather reports and watching where you should think about reefing or finding a safe place if it's going to get bad, you adjust and trim as a reaction to what's here and now.
Non sailers don't get how you can sail into the wind and to a point you can't (directly). Their concept is limited. As sailors, we harness the wind to allow us around 280-300 degrees of angle and we use tacking to fill in the rest.
After I reviewed what I said about the shroud indicators, I realized that my boat has spreaders and lowers are swept back. This may read differently than shrouds that are even with or forward of the mast. I would have corrected that in my post but editing is a pain on the app.
Please explain why it would make a difference? The tape is only connected to a small single point on the shroud. Shouldn't make a difference if the shroud is angled imo. It's still guided by wind direction.
I guess turbulence and for lack of a better term, back pressure on the windward side and like I mentioned, on the leeward side, the effect from the jib slot.
Point of sail of course impacts it too. Like I said, my ignorance may be showing, it's just my observation and my thoughts on why. Not trying to be contentious by any means, hence my admission and requests for correction.
As for the shrouds being behind the mast laterally, it's going to be subject to the turbulence from the main more than if it were before the luff in my opinion.
Point of sail of course impacts it too. Like I said, my ignorance may be showing, it's just my observation and my thoughts on why. Not trying to be contentious by any means, hence my admission and requests for correction.
As for the shrouds being behind the mast laterally, it's going to be subject to the turbulence from the main more than if it were before the luff in my opinion.
You're absolutely right doc that the apparent wind reported by shroud mounted telltales and wind vanes will be inaccurate due to the effects of the sails. Essentially, the sails bend the wind into a lift in front of their leading edge, and into a header off the trailing edge. For this reason a masthead windvane is the most accurate, and it should be balanced such that heeling won't affect it much. As you say though, the wind can be different at sea level vs mast head (called shear) which you can perceive bay watching telltales at different heights on the leading edge of the jib and checking how the luff breaks.
Yeah it's one of my all time favorites even if it's not an actual portrayal.Doc,.....I'm your Huckleberry (been watching Thumbstone again)Makes sense I reck'n.
On the shroud tells, you use the windward tell. The leeward tell is distorted by air flowing through the slot between the headsail and mainsail. The fact that a shroud tell might help you see the lift effect of the headsail on the mainsail(pushing apparent wind aft) is not bad information. After all, it is apparent wind that you trim your sails to.
Geez Louise! I'm not confusing POS diagrams with the boat's wind gauge. FYI: I'm an ASA Instructor. Someone needs to annotate those diagrams to explain that the WIND direction (arrow at the top) is the APPARENT wind direction unless the boat is either fixed (as it is in the diagram-but which never happens on the water), pointing head to wind, or headed dead down wind. Maybe I'll fix those diagrams some day myself. Hey--dudes, if you want to know the "True" wind direction using the compass, then put the boat head-to-wind for a second or two and get the (reciprocal) compass heading or bear off to DDW and read it there. Even then you will not have the TRUE wind direction for navigation unless you correct the compass heading to true heading (variation & deviation corrections), etc. On any other heading with boat underway the Point of Sail is relative to the APPARENT wind.
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