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post #1 of Old 09-13-2016 Thread Starter
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ST60 Wind Transducer does not show correct true wind

I've registered for the Raymarine support forum, but their site admins are taking their dear old time approving my membership. In the meantime, I am hoping that one of you might have a hint or two to help me address my problem:

My configuration:

I have ST60 Wind, Speed, and Depth transducers, ST4000+ wheel pilot, and a Garmin 2010 chartplotter. These instruments came with my new (to me) boat. I did not install them.

My speed transducer's paddlewheel is sitting in the bilge. I have the blank in the through-hull, and have the speed control head set to display SOG.

My background:
I have had Raymarine ST60 instruments on a past boat, and have quite a bit of interfacing experience with SeaTalk and NMEA 0183 protocols.

What works:
My wind transducer shows apparent wind fine. It may need a little tweaking of the calibration, but it's not terrible, and I have more important things to fix first.

What's broken:
The wind transducer is not showing the correct true wind. It shows exactly the same speed for true wind that it does for apparent wind, regardless of speed or direction of the boat. True direction is also almost the same too (within a few degrees). I can be motoring 5 kts straight into a 5 kt wind, and both true and apparent wind will show up as 10 kts. I can be sailing on a broad reach, and true/apparent wind speed are the same, and direction almost exactly the same. The direction agrees with visual observation of my masthead Windex.

The first hypothesis might be that the instrument is not getting any speed data, or is getting a value of zero (since true=apparent when speed=0). But the speed control head shows SOG just fine. Although I have not opened up the NavPod to view the wiring, I assume that the chartplotter's output wires are connected to the NMEA input terminal on the Autopilot, and the Autopilot is passing that data through to the SeaTalk netowork. That's the only way I can see that the speed control head would be able to display SOG.

So this leaves the question: Why isn't the wind transducer making the appropriate vector calculations to display the correct true speed and direction?

I've looked through the manual and cannot find any settings to change speed input (for instance, from SOW to SOG). So I'm stumped.

Rick S., Swarthmore, PA
USCG Certified Captain, OUPV and 50 Ton Master
ASA Certified 101/103/104/105/106

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2001 Catalina 34MkII Tall Rig Wing Keel Breakin' Away, Universal Diesel M35B, Mantus 35 lb. anchor, sailing out of Rock Hall Landing Marina

Last edited by TakeFive; 09-13-2016 at 01:54 PM.
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