B&G Deckman - Manual (Page 126)

Wind speed and Wind angle
8.3
Figure 8.2
For each wind speed there are three points, rather than five, each of
which has two values: the a column specifies the original true wind
angles and the v giving the correction to be applied. Positive or negative
values can be entered; for wind angles, a negative value offsets to the
West, a positive to the East.