Wind Instrument

[RaymondR]

Originally Posted by Paul L

Maybe it's a language issue, but you are really misstating what these standards reference. The CAN bus, which Nmea 2000 is layered on, has absolutely nothing to do with rs232 or 422 or 485. It is a completely different animal at the hardware level.

I have a couple of USB to RS422/485 converters I have used for years to connect my computer to serial comms systems. I did not ever notice that they did not work but now having been informed that they don't I'll have to throw them away. Bit of a pity, they were good trouble shooting tools.

[s/v Jedi]

For wind sensor data, I believe racers use a wind sensor in front of the bow for upwind sailing instead of at the top of the mast. They mount it to the pulpit.

The reason B&G autopilots are so good is that they actually are Robertson autopilots. I believe they are still made in the Robertson plant in Norway.

RobNet was from Robertson; they are the small red connectors. Simrad had SimNet, which looked like the RobNet connectors but were yellow. They were CANbus and compatible with NMEA2000.
I once had a Simrad pilot with two RobNet and two SimNet connectors on the back.

[Tehani]

Originally Posted by Group9

We never could get our old Raymarine wind speed gauge calibrated. But, we found if we took the recorded speed, and multiplied it times two, it was pretty close. I found I could live with that.

A magnet in the anemometer may have popped.

[Tehani]

Originally Posted by s/v Jedi

For wind sensor data, I believe racers use a wind sensor in front of the bow for upwind sailing instead of at the top of the mast. They mount it to the pulpit.

The reason B&G autopilots are so good is that they actually are Robertson autopilots. I believe they are still made in the Robertson plant in Norway.

RobNet was from Robertson; they are the small red connectors. Simrad had SimNet, which looked like the RobNet connectors but were yellow. They were CANbus and compatible with NMEA2000.
I once had a Simrad pilot with two RobNet and two SimNet connectors on the back.

Probably the AC40 and AP16 set. This was still Robertson, renamed Simrad.

[Joli]

Originally Posted by s/v Jedi

For wind sensor data, I believe racers use a wind sensor in front of the bow for upwind sailing instead of at the top of the mast. They mount it to the pulpit.

Maybe they have this in addition to a mast head MHU but I doubt that would be all they have.

[lateral]

I had my network crashing and isolated to the ultrasonic wind cable (PB200) at masthead. Of course I could isolate and terminate at mast step to get network up again. So so after some time sailing with no wind data decided in a fit of boredom to try and make the stuff work.
Between CanL and CanH did not read infinity (dissconnected), no corrosion/water entry.
Pulled cable and dissected top proprietry connector, finding porous rubber and inadequate separation of L&H. Cast a new plug off a mold re-insulated terminals.
Never failed again. (5yrs now)
Now the only "clue" that I could follow was < 10Mohm resistance between canL & canH. Which is insignificant in terms of the 120ohm termination, but I persisted anyway.
Perhaps it was something else and I happened to fix it in the process?
I'm happy with taking oppositions own goal!
Damn, I worked for it though.

[Paul L]

Originally Posted by RaymondR

I have a couple of USB to RS422/485 converters I have used for years to connect my computer to serial comms systems. I did not ever notice that they did not work but now having been informed that they don't I'll have to throw them away. Bit of a pity, they were good trouble shooting tools.

Who told you they didn't work? I told you the rs232/422 had nothing to do with nmea2k or CAN bus. Guess it is a language issue.

[s/v Jedi]

Originally Posted by Joli

Maybe they have this in addition to a mast head MHU but I doubt that would be all they have.

Like I wrote, they only use that sensor for upwind. This however, is the point of sail where correct wind data is most crucial.

[s/v Jedi]

Here, just in case a pictureto make things clear: wind sensor, mounted at and forward of the bow.

[Joli]

Originally Posted by s/v Jedi

Here, just in case a pictureto make things clear: wind sensor, mounted at and forward of the bow.

They're probably using that in conjunction with a MHU to measure gradient and shear. Again, I doubt that a sea level wind indicator is the primary wind indicator.

[wingssail]

Originally Posted by s/v Jedi

Here, just in case a pictureto make things clear: wind sensor, mounted at and forward of the bow.

Well, that's a picture of the British AC boat and I know that all the AC35 boats are so equipped but do you have knowledge of a trend by other boats to this?

I have not noticed it other than the AC boats and some catamarans.

[s/v Jedi]

Originally Posted by wingssail

Well, that's a picture of the British AC boat and I know that all the AC35 boats are so equipped but do you have knowledge of a trend by other boats to this?

I have not noticed it other than the AC boats and some catamarans.

You mean cruising monohulls?

[Joli]

Originally Posted by wingssail

Well, that's a picture of the British AC boat and I know that all the AC35 boats are so equipped but do you have knowledge of a trend by other boats to this?

I have not noticed it other than the AC boats and some catamarans.

The only reason I can think to measure wind speed at the surface is so you can compare it to the mast head. I would guess they are analyzing the gradient and changing the camber along the luff to match a gradient at a specific height? Does anyone here have experience on an AC campaign? It would be interesting to know if the main can be camber controlled at different heights.

[wingssail]

Originally Posted by s/v Jedi

You mean cruising monohulls?

Originally Posted by s/v Jedi

For wind sensor data, I believe racers use a wind sensor in front of the bow for upwind sailing instead of at the top of the mast. They mount it to the pulpit...

Jedi, I was asking if you are aware of a trend towards this, I am not.

[wingssail]

Originally Posted by Joli

The only reason I can think to measure wind speed at the surface is so you can compare it to the mast head. I would guess they are analyzing the gradient and changing the camber along the luff to match a gradient at a specific height? Does anyone here have experience on an AC campaign? It would be interesting to know if the main can be camber controlled at different heights.

No actual experience with an AC campaign but we've seen plenty of discussions about the mechanics of the wings. At least two (sometimes three) segments going up the sail, each of which can be trimmed independently, both angle to the wind and shape, effectively introducing twist differences, and the shape to accommodate different true/apparent wind speeds.