Wind Instrument Quandry

[D Stevenson]

Hi All, new to the forum so thanks for having me.

I’m soon to complete my catamaran build & have a curly question regarding mounting a wind instrument and seeking advice.

My Cat is 36ft and is biplane rigged mast separation is 13.5ft approx & the masts are free standing and rotate in sockets.

Without mast rotation compensation I’m looking for the best compromise on locating a wind instrument on its own pole.

Option 1 - central near bow maybe 8 -10ft above the water is a reasonable location but will be compromised when sailing down wind

Option 2 - midway between the masts central but this would need to be lower - not much higher than the bridgedeck

Option 3 - aft central set higher similar to bow but would be compromised sailing up wind…

Ive got the instrument and didn’t even think about the rotation of the masts until I was reading the instructions. Not racing just cruising so I figure stable slightly inaccurate data from time to time will be good enough. Less than ideal I know but having something is probably better than nothing.

I would like to feed wind data to autopilot so that will have a bearing on best location I’m sure as some points are better sailed to a bearing than wind. The boat will be fast as well - it’s very light and well powered in terms of sail area.

Thanks in advance

[noelex 77]

Welcome to the forum.

That sounds like an intriguing vessel. Including a photo would help answer your question.

I imagine that any cat with rotating masts it will bring the apparent wind forward much of the time so a bow mounting would be my preference. There are ways to compensate for a rotating mast and this would be better. If nothing else it will avoid a rather ugly pole at the bow.

[D Stevenson]

Thanks Noelex77,

Not sure how to attach an image yet, the Build is Schionning Radical Bay 1060, reversing the bows took me to exactly 11m from the initial 10.72m in the design. Very light 2600kg. max displacement made with the superlight version of duflex and durakore.

I’ve gone with Garmen Instruments and doesn’t look like mast rotation compensating Nexus stuff exists anymore - I think if I want rotation compensation I’d need to offload and go with some other solution.

Thanks

[Tin Tin]

Does this not work ?
"The Raymarine Wireless Mast Rotation Transmitter is a unique transmitter that compensates for the movement of a rotating mast to ensure that you get the most accurate wind readings at all times. Operating as a wireless device on a Micronet network the Mast Rotation Transmitter compares compass information from the boat with its own information and corrects the wind angle coming from a standard wind transmitter at the mast head".

[D Stevenson]

Hi Tin Tin

Thanks for that. I did read about the tick tack mast rotation transmitter from raymarine this morning but it seemed like it would only work with a wireless raymarine wind setup. I would have to ditch the new Garmin gwind and change gear but maybe that’s ultimately the way forward. I might try the Garmin jury rigged to start and see how god or bad it goes… haven’t got much to loose if I’m going to ditch it…

Never had wind on the previous vessel and used a simrad tiller pilot, the motivation for wind was sending some data to the autopilot… can sail to a course it the wind data isn’t stable or useful - just looking for a cruising solution so stability of the instrument and knowing what points of sail it works or doesn’t is all I need.

If it reads a bit low because it’s not as high or gets blanketed while going down wind I’ll use it accordingly.

Maybe a bit of trial and error before making a swap…

Cheers

[bergius]

LCJ Capteurs has a rotating mast version of their ultrasonic wind sensor:
https://lcjcapteurs.com/en/girouette...vent/cv7-rm-2/

We have the “regular mast” model, and it integrates without problems with our B&G gear. I assume wind sensor data is standardised well enough in N2K to work across vendors.

[D Stevenson]

Thanks Bergius

Will see what I can find out.

Cheers