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post #34 of Old 04-08-2012
Stu Jackson
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Re: Garmin GPS 72H and VMG?

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Originally Posted by danielt63 View Post
And what I'm saying is that the waypoint above should *not* be based on wind direction, precisely because (as you mention) it isn't consistent. Instead, put the waypoint far above the line created by the upwind mark and downwind marks. You don't necessarily want the best upwind VMG (after all, if the wind shifted 60 degrees during your upwind run, making best upwind VMG would be a huge mistake!) What you want is the best VMG up the line to the mark. My waypoint placement will give you that, no matter where the wind is coming from.

As for your second waypoint. Yes a waypoint at the mark to help judge laylines is nice, but few GPS units will give you VMG toward two different waypoints at the same time.

Thanks for that detailed explanation. Great point.

It seems that there are really three useful VMGs.

I agree about the visibility of those two or three VMGs. One one unit, you'd have to switch back and forth. My GPSMap 76 Cx has a handy and easy to use "Recent Waypoints" funtion. Or, you could use a backup GPS.

Always nice to learn something new.

Thanks again.

Stu Jackson, Catalina 34, 1986, M25 engine, Rocna 10 (22#)
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