B&G Deckman - Manual (Page 124)

Wind shear
8.1
Chapter 8 : Wind calibration
The additional features for wind calibration in Deckman are very
important—with these you can fix the problems of getting a true wind
direction which is consistent from tack to tack.
Deckman takes the original data from the instrument system
(Orig_TWS, Orig_TWA, Orig_TWD in Show Data on page 5.4),
applies offsets to the angles and speeds according to the values in the
tables, and generates new variables (TW_Speed, TW_Angle, and
TW_Dirn) which are used in all calculations in Deckman and can be
sent back to the instrument system. Calibrations need to be entered for
the original wind speeds and angles, not the required corrected value.
For instance, in Figure 8.1, the required wind angle for optimum upwind
VMG in 4 knots is 65°, but the original data was 60°. A +5° correction
has therefore been applied at this wind speed and angle.
Wind shear
A consistent offset to the true wind direction to adjust for the effects of
wind shear can be entered by choosing polars>adjust wind shear. A
negative value offsets to the West, a positive to the East.
Wind speed and Wind angle
In the polars menu, choosing adjust wind speed or adjust wind angle
allows you to set values for offsets in either of these two things. They
have the same format and work in the same way as the polar tables (see
Figure 8.1and Figure 8.2 below).
You are also able to have different copies of the wind speed and angle
correction tables saved. These also work like the polar tables: to view
the currently loaded table, select polars, followed by adjust wind speed
(or angle), then show>loaded. You then have the option to save file