B&G H2000 Pilot *DISCONTINUED* - Manual (Page 69)

HB-0845-06 69
The h2000 calculates the optimum VMG from the polar
table for the wind speed and then compares this to the VMG
actually being achieved, displaying the result as the tacking
performance percentage. The same problems of time lag
exist here as they do with VMG, this is discussed in the
section on VMG.
0˚
10˚
20˚
30
˚
40
˚
50
˚
60
˚
70
˚
80
˚
90
˚
100
˚
110
˚
120
˚
130
˚
140
˚
150
˚
160
˚
170˚ 180˚
170˚
160
˚
150
˚
140
˚
130
˚
120
˚
110
˚
100
˚
90
˚
80
˚
70
˚
60
˚
50
˚
40
˚
30
˚
20˚
10˚
10
8
6
4
2
3
5
7
9 Kts
Boat Speed
Target Boat
Speed Downwind
Target Boat
Speed Upwind
Optimum True Wind
Angle Upwind
Optimum True Wind
Angle Downwind
Maximum VMG
Upwind
Maximum VMG
Downwind
True Wind Angle
Port Tack
True Wind Angle
Starboard Tack
Figure 4 - Polar Performance Curve
The advantage of tacking performance over VMG is that it
takes into account changes in windspeed. You should also
be aware of the potential inaccuracies caused by your polar
table being incorrect.