Question on Instrumentation

[bottomscraper]

The "true" wind display shows speed and direction but the direction is relative to the bow of the boat not a compass direction. If the instrument had both track and heading it could calculate a true wind compass direction. I suspect some of the newer integrated systems can do this but I don't think the ST60 wind instrument knows either. I still don't think the impeller speed would be relevant, I'm not saying it isn't useful for knowing something about current!

[Dean Abramson]

Oh, I didn't realize that a wind gauge (which has True) did not show compass bearing, only relative.

No big deal, if you can add/subtract. And that's if you even care about compass direction of the wind, which maybe is somewhat academic anyway.

I wouldn't mind knowing True wind speed, because when I'm sitting in a tavern and telling my barmates "It was blowing a steady 30 knots out there," I would know how much I'm exaggerating by.

If everything is operating correctly, do you just toggle between True and Apparent with a button on the face of the gauge, or do you have to go into a menu and set one or the other?

When you lose the knotmeter data, what happens? The gauge reads zero degrees/zero wind in the True mode, but shows the Apparent stuff okay?

[bottomscraper]

If everything is operating correctly, do you just toggle between True and Apparent with a button on the face of the gauge?

Yup

When you lose the knotmeter data, what happens? The gauge reads zero degrees/zero wind in the True mode, but shows the Apparent stuff okay?

Well if the impeller is completely stuck the unit thinks the boat is stationary so true & apparent will read the same. (so basically they both show apparent wind). If the impeller is just slow the apparent will still be correct but the true will be different but not correct.

If your anchor is holding it reads true and apparent correctly

[Neil Gordon]

The paddle wheel has never been a reliable source of speed, as it's nearly impossible to calibrate. It's never quite 100% clean and the wheel's drag is no doubt different at different speeds. I also suspect different flow over the bottom on port vs. stbd tacks gives me different readings. That said, it's an accurate measure of relative speed as I make sail adjustments or as the wind picks up or dies down, it has a water temperature feature and I make use of the timers on occasion.

[Dave and Kathy]

Thanks, all! As always a wide range of perspectives, but all good info.

We brought Grayce back from Maine ourselves in the summer of 2010. She's inside my shop and we started at the bow working our way back. The interior will complete in a couple of weeks, and then I'll start on the exterior. Re-bed all deck hardware and redo the non-skid with KiwiGrip. I'm happy with steady progress - Josephine (Typhoon) is in the water and satisfies the sailing fix. I'd love to share photos on the Projects page, but haven't figured that out yet.

Dave and Kathy

[gates_cliff]

I am always amazed at the information available here. I never had trig or anything like that in high school and was a Sociology/History major in college. So much of this discussion escaped me, just like much of what goes on in life. I remember hearing a coach say once, "there are 3 kinds of people, those on the court or field participating, those on the sideline wishing they were, and the rest just wondering what is going on!" I could very possibly fall in the last category.

Nonetheless, my boat doesn't have a knotmeter, wind vane or wind speed, or even a GPS, although I do own a hand held. But, it seems to me that it would be more valuable to have a windvane/speed and GPS than a knot meter.

Anyway, thanks as always for the amazing information here.