SailNet Community - View Single Post - Garmin GPS 72H and VMG?
View Single Post
post #33 of Old 04-08-2012 Thread Starter
Junior Member
Join Date: May 2011
Posts: 15
Thanks: 0
Thanked 0 Times in 0 Posts
Rep Power: 0
Re: Garmin GPS 72H and VMG?

Originally Posted by Stu Jackson View Post
1 --- The 1,000 mile away waypoint which should be based on wind direction (assuming it is constant, which we all know it is not). The CONCEPT here is to get the best UPWIND VMG based on the wind direction, since the start line is not always exactly perpendicular to the true wind direction, and the first waypoint is not always exactly dead upwind. It alerts you to the favored tack. The 1,000 mile away waypoint should be on the same bearing as the true wind direction.
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.

Last edited by danielt63; 04-08-2012 at 12:45 PM.
danielt63 is offline  
Quote Share with Facebook
For the best viewing experience please update your browser to Google Chrome