[LW] [LW11] ST60 True Wind Speed and Angle

[Planke]

Hello,

while sailing downwind our ST60 displays a TWS which is lower than AWS and the TWA is more ahead compared to the AWA.
Since I can't imagine a situation where this could be true there must be something wrong with our installation.

Log data is provided by a ST60 Tridata via Seatalk and the STW indicated on the display is reasonable. Since TWS and VMG are disiplayed on the ST60 Wind the speed data is received.
Could you imagine what is going wrong? What should I check first?

Kind regards
Ralf

[Louise - Raymarine - Moderator]

Dear Planke,

Thank you for your post.

Can you inform me of the wind angle, true wind speed, apparent wind speed and speed through the water when this occurs?

Is the wind instrument displaying accurate wind information?

Many Thanks
Louise

[Planke]

Dear Louise,

it occurs on typical wind angle when sailing downwind.
E.g. the apparent wind reads 160 degree portside, then the true wind angle will be more ahead then the apparent wind angle. I have observed this for light winds to strong breezes (force 2 till maybe 6), for STW from 3 to 7 knots. I am sorry, I haven't recorded the values.

STW seems to be correct and is in reasonable accordance to the SOG reported from GPS. I checked the wind angles by rotating the wind vane on top of the mast to well-defined angles while my mate read the angles on the display.

Kind regards,

Ralf

[Louise - Raymarine - Moderator]

Dear Planke,

Do you have the long or short arm wind vane?

It could be down to an updraft of wind from the sails influencing the wind vane on this particular angle of sail. The alternative option is to send the ST60 in to us for testing and this can be done online here. There is also a FAQ on the forum on testing your wind transducer with a multimeter, this can be found here.

Many Thanks
Louise

[Planke]

Sorry for the late reply. I was on my boat the last weeks.

What I did: I run the Selftest as described in the Service Manual.
While running the calibration of the direction indicator in 30° steps, I noticed that some where heavily misaligned. Afterwards I started the user calibration and realigned the zero degree position.

Now the change in the wind angles are reasonable, when switching from apparent to true or backwards.

Kind regards
Ralf

[Louise - Raymarine - Moderator]

Good to hear things are working.

Thanks Louise