Finally, a wind instrument that will work with a Mac!

[BOAT]

But the Raymarine stuff breaks all the time, I know my ST50 wind unit has had 2 wind senders on it before the PO gave up, probably from frustration and empty pockets, lost of the Raymarine stuff is now made in Asia, just like every other brand

The RayMarine tiller drive and brain are made in Hungary. The p70 heads are made in China.

I don’t know about the RayMarine wind sensor because I did not get one – why would I? They don’t have one for a rotating mast! If you want a rotating mast sensor from RayMarine they will send you to one of their subsidiaries called TAC-TACK and that's a solar unit and all the problems of wireless associated with that.

I got the Pegasus unit, but really, I don’t expect any of these sensor units to last a real long time if you’re going to leave them up in the air 24/7 in the weather. None of them will last more than 5 or 6 years in constant use. They are “wear items” (and a real pain in the ass to replace if your slipped) and another reason why I did not want a solar panel and batteries up on the mast. Removing the sensor when not on the water helps (also a REAL pain in the ASS!). Otherwise, they are all going to wear out pretty fast with only one exception:

Like I said in a previous post – if you want a really good sensor up on your mast that is the most accurate and bulletproof long life that will last a LONG time you need to go with a ultrasonic sensor – they have no moving parts – they are far superior. If I could get one for a rotating mast that was my first choice – but no one makes one. I tried and tried to get someone to make a unit that would work with an ultrasonic sensor but no one really wanted to do it.

So just get any plastic cup spinner and wind vane and expect them to wear out – just figure on replacing them after every 5 years of continuous use. Anything with moving parts is not going to last.

[Baha]

I was thinking about this thread while out on the water this week and just wondering why I would every need a wind instrument. I am out in an area known for gusty, swirling winds, and don't even use a windex...just try to keep aware of what the wind is doing by watching and feeling for it. If I was racing it might be different, but I think it is a lot of fun to try to find the wind without electronics. I might break down a hand a pennant from the mast though....

[BOAT]

I was thinking about this thread while out on the water this week and just wondering why I would every need a wind instrument. I am out in an area known for gusty, swirling winds, and don't even use a windex...just try to keep aware of what the wind is doing by watching and feeling for it. If I was racing it might be different, but I think it is a lot of fun to try to find the wind without electronics. I might break down a hand a pennant from the mast though....

Your right baha, you don't need one - I used nothing at all on 'boat' for that past 5 years except a wet finger when the wind was light. Even with the sensor or tell tails I pay no attention to them - for one thing I am older now and it hurts my neck to look up - I'm just too stiff now. The wind is on the plotter but I don't bother - I did not even pay attention to it on the pilot until kurz asked me to look at it.

The only thing I use the sensor for is for the Auto Pilot - that's it. The AP does not have any fingers so it can't tell what direction the wind is going. That's why I have the sensor. The only reason. If I were in an area where I could not cruise for hours on a leg with all kinds of obstacles and wind changes I would not even have an auto pilot - I would just be at the helm all the time. But, that's not the situation I am in:

I am out in the ocean and the only time I get on the helm is going out of the harbor, coming back in, or tacking the boat. Most of the time I am roaming around on the deck playing with the rigging or down below looking at charts or the Garmin Ipad Blue Chart or laying down in the cockpit talking to the wife. I'm fair skin so I spend a lot of time hiding from the sun (behind a sail, under a bimini, below decks, ect). If I sat on the helm all day I would be a red as a lobster by the time we got in. As it is I wear huge floppy hats that also work well as wind indicators.

[MikeFloutier]

This is what I want a wind sensor for, the AP.

And that is exactly why I don't see what difference the rotating mast makes. Set the sensor up for straight ahead of the mast THEN when you want the AP to sail by the wind (ie keep the boat's heading at a fixed angle relative to the wind) you just switch on Wind mode. The wind moves 10 deg to port, the boat turns 10 deg to port. The mast does not rotate!

The mast rotates when you tack or gybe but the whole thing about sailing to a fixed wind angle is that, not only do you not tack or gybe, you don't do anything that will cause the mast to rotate.

My suggestion is that this whole rotating mast issue is a bit of a red herring for the average cruiser.

My remaining problem is finding a wind sensor that can talk the long deprecated NMEA 0183 sentence "VWR" to my RM st2000 AP.

I looked at Arduino and Raspberry pi to handle the input, output and translation but in the end decided it wasn't worth the combined small expense but huge learning curve.

I'm waiting to hear from RM, how they explain not updating this NMEA sentence (that's been obsolete for nearly 10 years) on a current product.

[Phil M]

This is what I want a wind sensor for, the AP.

And that is exactly why I don't see what difference the rotating mast makes. Set the sensor up for straight ahead of the mast THEN when you want the AP to sail by the wind (ie keep the boat's heading at a fixed angle relative to the wind) you just switch on Wind mode. The wind moves 10 deg to port, the boat turns 10 deg to port. The mast does not rotate!
...

Perhaps when sailing close-hauled, and the 10 degree wind movement stalls the sails, but any other point of sail would you not rather keep the same heading and adjust the sails accordingly? A wind sensor for the AP would be only minimumly useful, I would think.

[BOAT]

This is what I want a wind sensor for, the AP.

And that is exactly why I don't see what difference the rotating mast makes. Set the sensor up for straight ahead of the mast THEN when you want the AP to sail by the wind (ie keep the boat's heading at a fixed angle relative to the wind) you just switch on Wind mode. The wind moves 10 deg to port, the boat turns 10 deg to port. The mast does not rotate!
...

Perhaps when sailing close-hauled, and the 10 degree wind movement stalls the sails, but any other point of sail would you not rather keep the same heading and adjust the sails accordingly? A wind sensor for the AP would be only minimumly useful, I would think.

Right, the wind sensor is really only for long distance cruisers - It does not become practical until you have legs at least 10 to 20 miles long. What you do is tell the pilot to sail to a waypoint, NOT a heading. Then the Pilot will average out the best heading as the wind changes to make sure you end up at that way point in the fastest possible time. When the AP controls the helm it will change the course as the wind changes to try to optimize the sail trim. The wind is always varying a little back and forth and the pilot can follow that and get you to your destination.

Ever look at your GPS speed and watch it vary from 6 knots down to 5 and them back to 6 and you play with the sails trying to hold at 6 knots but nothing you do does it? Well that's because the problem is not the wind dying it's because of the wind shifting - it does that all day long. The natural shape of wind is a wave form. If you can follow the oscillation you can maximize your overall speed to destination.

[MikeFloutier]

Yes, that's what I want!

I'm looking at a trip from Falmouth to the Isles of Scilly which is between 60 - 70nm depending on the wind; most of it being coastal or off-shore.

That extra knot could mean 2 to 3 hours off the trip time. With that length of trip, even two-handed, it would reduce a lot of tiring workload. Helming and trimming is only a novelty for so long on a long trip (says he whose longest trip so far was around 5 hours - didn't quite make it round the world:))

Just got to find a cheap wind direction sensor that will talk "old-NMEA 0183" or some other workaround.

Anyway, do you take my point about the rotating mast, i.e. it doesn't rotate until YOU rotate it by tacking after 5 hours on a fixed angle of 50deg to the wind. Then, with the mast in it's new position, you steer at whatever-you-want to the new wind and punch that button on the AP that says "follow that wind"; and it does.

It would only trip up if your mast moved, but why should it? If you've got your shrouds at a decent working tension you may even have to help it round when you tack.

[BOAT]

Mike, there is a problem with that because (a lot of people don't know about) but when you get a wind vane set up for the first time it needs to go through some calibration and if it's electronic connected to a plotter or pilot it needs some initialization too - if you do what your planning to do you will need to go through the entire re-calibration and re-initialization process every time you tack the boat!

The reason they have the calibration is because there is no way for the manufacture to know if your mounting the van on the middle of the mast, out in front of the mast, on the back of the mast, or to one of the either sides of the mast - some people have so much stuff on their mast they have the vane mounted upside down! Anyways, the BASE of the vane that attaches to the mast tells the system where the front of the boat is at the time, NOT the vane! You need to be able to mount the BASE in any configuration, and then set that configuration as "straight ahead-forward" so the system has a starting point.

If you move the BASE of the vane, now it does not know where "straight ahead-forward" is anymore and you need to re-calibrate it, and re-initialize your system! That's going to be a huge PITA. And the worse part is how are you going to re-calibrate "straight ahead-forward" with the unit flopping around in the wind 40 feet in the air?? I calibrate my vane in the driveway with the mast down and the vane blue taped in the "straight ahead-forward" position. Even with the mast down I need a ladder to reach the vane to tape it from moving so I can set the calibration. Thank God I only need to do that once a season at the most.

[Tomfoolery]

Now I don't feel so bad that I took the wind instrument that came with my well-used boat off and put it in a box in the basement. Then added a Windex (and have since broken off the 'tack' limit indicator arms and don't care) and added a window in my bimini so I can see the vane while sitting on the helm seat.

But then, I don't mind sitting at the helm and steering for very long periods, and don't have an autohelm anyway so even with a wind instrument, I'd still have to steer. Or balance the helm with the sails and don't steer. Whatever.

As to measuring mast rotation angle, I would think you'd get better reliability using a digital rotary encoder (absolute) than a pot. But that'll cost. Of course.

[BOAT]

Now I don't feel so bad that I took the wind instrument that came with my well-used boat off and put it in a box in the basement. Then added a Windex (and have since broken off the 'tack' limit indicator arms and don't care) and added a window in my bimini so I can see the vane while sitting on the helm seat.

But then, I don't mind sitting at the helm and steering for very long periods, and don't have an autohelm anyway so even with a wind instrument, I'd still have to steer. Or balance the helm with the sails and don't steer. Whatever.

As to measuring mast rotation angle, I would think you'd get better reliability using a digital rotary encoder (absolute) than a pot. But that'll cost. Of course.

Yeah, Tom, I'm not sure what kind of compensator unit Chris uses - he has been selling those from his Oregon business for several years now as I have followed along his and also other units including the big belt driven ones the catamarans use (which had the highest accuracy scores of all the ones I researched). I think they all use magnets, but I really don't know - if Chris is reading he can jump in and tell us how the compensator in the base of the mast works. I can only assume his sensor is analog, like you say, because the optional meter he sells with the unit is also analog just like the catamaran units. The analog units have unlimited variability of display but at the cost of no discreet point reference in between min to max. Thus, the starting point calibration - having a point that always takes you back to zero keeps the unit accurate. Of course, a discreet digital sensor would not need such calibration - it would just tell you which digital point it's at in a choice of perhaps 360 discreet points (or in the case of the RayMarine AP 2160 points in nmea2000 or 1080 points in nmea0183).

Analog is all a moot point because of nmea0183 - or 2000 - makes no difference because all analog signals are converted to a digital discreet position by the encoder before it sends the sentence to the backbone anyways!! So you end up with e digitized position anyways, still, a stepper would be great, but probably not worth the cost on a system that only updates once every 1/2 second anyways! And that's the good ones! 90% of wind vane encoders only update the sentences once a second!! By then all those infinite points of reference end up in the trash anyways.

All you really need is nmea 0183 because the sentence is the same in 2000, there are just less points in 0183 but how many points do you really need between 360 points if parts of the system can't even use the points in between?? I got nmea2000 between the plotter and the AP and that's 2160 points on the compass - no wonder it can hold a heading to withing one degree! But really, it can do the same thing with 1080 points or even 720 points. The only time 2160 points on a compass is going to make any difference is if your an airplane on a transatlantic flight going from California to Istanbul or some far off place and you want the end point to be super accurate - only airplanes use that kind of digital accuracy - the RayMarine unit is reading a 3 axis sensor designed for an airplane - WAY overkill for a boat.

[MikeFloutier]

I recently wrote to Raymarine as their current st2000 autopilot seemed to be using ONLY an obsolete NMEA 0183 sentence and hence unable to receive wind data over NMEA.

This was their response:

The software in the ST2000 was based on a profile generated in the mid 90's - in fac, if you advise me the serial number of the unit I can be more specific, but basically the design was unchanged since the launch and only minor software updates through the late '90s Early '00s. I am afraid that there have been no changes to amend the spec since then. The other option is to use something like an MFD to connect to the NMEA from the wind unit and this will convert it to SeaTalk, which will then interface fine"

[BOAT]

I recently wrote to Raymarine as their current st2000 autopilot seemed to be using ONLY an obsolete NMEA 0183 sentence and hence unable to receive wind data over NMEA.

This was their response:

The software in the ST2000 was based on a profile generated in the mid 90's - in fac, if you advise me the serial number of the unit I can be more specific, but basically the design was unchanged since the launch and only minor software updates through the late '90s Early '00s. I am afraid that there have been no changes to amend the spec since then. The other option is to use something like an MFD to connect to the NMEA from the wind unit and this will convert it to SeaTalk, which will then interface fine"

Mike, I do not use a ST series AP, I use the Evolution series pilot. It uses either code, nmea0183 or 2000 - either one.

As for the ST2000 you can't expect a device built in the 90's to use nmea2000. nmea2000 (or what it really is: DeviceNet created by Allen Bradly) was not even invented yet when your device was made! How can it use Device Net when Device Net did not even exist at the time it was made???

nmea 2000 is called nmea 2000 because it was for devices made after the year 2000!

What's wrong with using nmea0183?

[MikeFloutier]

Sorry BOAT, I wasn't clear, I am using NMEA 0183. Modern wind instruments issue NMEA sentence "MWV" whereas the RM ST2000 still only listens for the old NMEA wind sentence "VWR" which was "deprecated" ie made obsolete in 2008. Marine equipment designers were advised to stop using it. See page 20 of https://www.nmea.org/Assets/20130801%20 ... 20list.pdf .

Hence my letter to them and their response in my previous post

[BOAT]

Okay, I see your issue now - yes it is true that the Pegasus unit that I use does transmit MWV. I did not know that your pilot would not read MWV.

Hmmm . . . . I need to think about that one - because an encoder would cost almost the same as a new AP power unit. (I will need to think on that one a bit).

[MikeFloutier]

As far as I can see there are 3 options:

1. Raymarine update the chip in the st2000 autopilot to recognize the current standard wind sentence "MWV" (obviously won't happen)

2. Build an Arduino or Raspberry pi device to accept NMEA 0183 sentence "MWV", translate it into Old NMEA 0183 i.e. "VWR" and form a suitable serial analog output. (I looked into this and found it to be a steep learning curve and fairly costly; especially for a one-off project)

3. Finally buy a ready made NMEA 0183 > SeaTalk converter. I have written to Actisense, who make this sort of thing to ask if they have a suitable box.

My feeling is that 3. is the way to go but I'm keeping an open mind.


Getting back to the real reason for this thread - i.e. Handling wind sensor data on a rotating mast - I would suggest having a longer think about it and perhaps accepting that it is, to some extent, a red herring.

1. As BOAT says, the only real use for wind data to an autopilot, to us on Macs, is on long legs, during which the mast doesn't rotate.

2. The AP doesn't need absolute wind direction, just the shifts, hence calibration is a non-issue, since a 10 deg shift from 090 is the same as a 10deg shift from 270.