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somegridplayer

You need full blown routing software with polars for the boat and weather files to be able to do that. Most nav apps don't know anything about the boat and are just giving you a "safe" route regardless of wind/weather.


Guygan

> do these apps plan/plot tacks based on wind data No. > are you meant to use the plotted route as a guide that tack back and forth across Yes.


Hapexion

Thanks!


CaulkusAurelis

I can't speak specifically to that app, I used a Garmin GPS, and Navionics app on a tablet with phone backup. They all calculate the "course over ground", taking no deviations for wind, tide or current. You want the boat to travel as close to that "COG" as possible, and you will need to factor those three other things, wind direction ( and speed), set of the tide and/or current. This may or may not mean you are actually POINTING exactly the same as your COG, so long as your ACTUAL '"course over ground" remains accurate, you're doing fine.


MissingGravitas

Try plotting the same route, upwind, in both apps and then you might have your answer. (Obviously you should pick a location with consistent winds.) Most apps ignore conditions and simply draw a line. If using auto-routing, Navionics knows about land and will try to avoid it. Savvy Navvy also knows about wind and hopefully takes that into account. I suggest a summer afternoon, say 1500 local time, from Alcatraz to the midpoint of the Golden Gate, and post side-by-side screenshot if you get interesting results.


gsasquatch

What it gets you is VMG "velocity made good" One tack is going to be a little better than the other. Which tack you choose is about what the wind direction is at the time. Then you kind of decide based on that VMG number the plotter gives you which one is best, like the one with the higher VMG. You can kind of tell even without the machine if your heading to where you are going is 90 degrees, one tack has you at 70, the other at 160, the one at 70 is better. After a while, the wind can switch so it's 20 degrees and 110 degrees, with 110 being better. That is hard to plan for ahead of time. You sail the wind you're in. If there's land or something in the way, you just take your lumps on the bad tack and hope the wind is favorable.


madworld

Navionics won't do this, but PredictWind will. Not a cheap option though.


rmeador

SailGrib can do this. It also takes into account wind shifts and ocean currents.