Re: [Amel Yacht Owners] Re: wind steer and VMS

Danny and Yvonne SIMMS

When you use  vmg the boats progress is optimised based on progress directly into the wind and the course would change with changes in wind direction. However you can have vmg to a waypoint which is quite different.
Another alternative is not to set vmg but set it to maintain a constant angle to the wind.
In this setting you can trim your sails to the optimum for that wind angle and sit back and the boats course will alter as the wind shifts. One trip from nz to Fiji Yvonne and I set 4 sails on a broad reach and didn't trim once in the six days it took to get there. As the wind shifted the boat went 20 degrees off to one side of rumb line and then came back on the next wind swing. We sailed a winding course but never too far off track. It could take 24 hours to come back but it always did.
A dream run.

SM 299 Ocean Pearl

Sent from my Vodafone Smart

On 16 Aug 2017 16:20, "svperegrinus@... [amelyachtowners]" <amelyachtowners@...> wrote:

Bill Kinney, I'm with Craig on this: I understand how VMG optimization works on Wind Navigation.  

I fail to see, however, how it might work on mere "W".  What would it optimize to, if it does not now where I intend to go to?  

Having said that, yesterday afternoon (1st day ever after checking the "VMG Optimization" checkbox), my wife the Admiral was W sailing... plain W-autopilot sailing you see, and the thing did what you described: it actually changed my wife's designated angle, one degree at at time.  But we are not clear on what exactly the autopilot thinks it was doing.  Surely there is a reason.


At anchor, Thermopylae

---In amelyachtowners@..., <greatketch@...> wrote :

No, "W" wind only mode works fine for the VMG optimization.  

I rarely use the "Wind Navigation" mode, and I am not sure exactly how VMG optimization would work there.

Bill Kinney
SM160, Harmonie
Gloucester, Mass

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