Drift to leeward
Post by iconPost by BooBill | 2019-11-24 | 15:34:11

It's pretty clear to me that VR includes a drift to leeward. If you set a heading to pass just to windward of an obstruction, over time your predicted path will drift down to hit the obstruction. That's a neat little complication that replicates one of the real challenges of sailing. There's a bunch more I'd love to see. Maybe that should be another thread though.

So, my question is, does the router take this into account? How is it quantified?

commenticon 4 Comments
Post by iconPost by zezo | 2019-11-24 | 15:56:26
That's not drift. It's a random rounding error and difference between client and server weather data.

It's been discussed a lot of times here, but in short there can be considerable differences between client (which displays your boat) and server (which actually moves your boat), especially during the wind update time. Can easily be observer in the Chrome extension data. Most difference in unstable weather like a ridge/center of a high.

Post by iconPost by BooBill | 2019-11-24 | 17:25:33

So, going through a transition zone you pretty much have to take over and hand steer. I've always seen that as a competitive opportunity when you tack/gybe at the moment of the wind shift, rather than on the router's discrete time steps

Is what you are saying, that what you see reported on the screen, is not actually exactly what's happening in the server, necessarily?
Post by iconPost by zezo | 2019-11-24 | 17:40:49
Yes. In a transition zone you can see a zig-zag route as a result of the client moving the boat one way and the server correcting the position every 5 minutes. It's safer using fixed TWA, otherwise you may end up with a bad angle.

Around the coast you better use waypoints. I did not follow my advice today and hit La Palma.

Post by iconPost by BooBill | 2019-11-24 | 19:44:29
LOL. I very nearly hit La Palma, but fortunately, I woke up at 5am and thought to check my programation wasn't drifting into the island.
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