Compass calibration on ST50 wind

[PaulMcC]

Hi All,

I was out at the weekend and noticed a fairly large deviation between the apparent wind direction at the masthead from the windvane and the apparent wind reported by my ST50 display. The speed calibration is fine.

I had a look in the manual which says after powering it up, turn through two complete circles to linearise the compass and then adjusts the offset so that the display knows where the front of the boat is (paraphrasing slightly!)

I did two relatively fast circles off Bembridge on Sunday lunchtime in fairly gusty winds and then adjusted the offset (through about 100 degrees) and all seemed well, however after a tack is was way off again so the linearisation have obviously not worked at all.

Any recommendations on how to do this step? Should I be aiming for slower circles? Do I need to do this on a day with steady wind? Is more circles better? Do I need to do anything in particular with the instrument before I start circling or will it just realise that's what I'm doing and start paying attention on it's own? Is there any was to tell immediately whether or not it has worked well?

Cheers

 

[RichardS]

On my ST60 I do the circles slowly - say 30 secs to make each turn - but the ST60 then flashes and beeps to tell you it has registered so you can keep going for another circle if it doesn't register. Perhaps the ST50 doesn't give the feedback?

From memory, I think you need fairly stable wind and sea conditions but it might be that I only notice it's out when the breeze is stable and then decide to reset it.

Richard

 

[PaulMcC]

No the ST50 gives no feedback that I can see. Guess I'll just have to try a few more circles next time I'm out when the weather is a little bit more stable.

 

[Ricd]

Had similar problem with ST60 couple of years ago. Did the turning calibration thing a few time and it read correctly for a short time each time before suddenly miss reading wind direction, usually just post a tack. End result was england never checked the control head and condemned it. New PCB and all has been well ever since.