On Fri, 10 Oct 2008 21:21:13 +0200, Ulrich G. Kliegis
wrote:

Folks,
Has anyone else observed this:
The Navico Corus instruments can compute VMG when a log sensor and the
masthead unit (wind direction and speed) are available.

Now, the wind direction sensor needed a corrective offset on my boat,
although mounted very straight. The manual says that this is normal,
and under all other conditions, the readings look alright. Other than
the computed VMG. On one bow, I get phantastic values, coming close to
90% of vtw when beating close-hauled, on the other bow, this breaks
down to a meager 20% or so.

Did the guys (i know that the old Navico company was dissolved some
years ago) forget to include the offset in the VMG computation?

Thanks for any enlighting information.

Pardon my ignorance, but as I understand it, VMG is an averaging
function (Velocity Made Good) from point A to point B and Vtw is
measurement of true horizontal wind speed.

If Vtw is used as a function of VMG, (1) why would you need to offset
any value - it should be the same on either tack (port/starboard) if
the sensor is positioned properly.

Yes/No?