B&G H2000 Pilot *DISCONTINUED* - Manual (Page 80)

h2000 User Manual
80 HB-0845-06
VMG can measure the performance upwind and downwind
much more effectively than boat speed, since it takes into
account how close the boat is sailing to the wind. However,
it is not possible for the helmsman to sail to it directly
because of the momentum of the boat. As the boat sails
closer to the wind, the VMG will initially rise because the
boat will hold its speed due to the energy contained in its
momentum. VMG increases, and the helmsman, seeing this,
would be encouraged to sail even closer to the wind thus
increasing the VMG still further. Ultimately the boat will be
head to wind and stop dead. VMG will then drop.
Because of this, the technique has been developed of
analysing the boat’s performance to find out at which speed
the greatest VMG occurs.
Once this is known the helmsman steers to this target boat
speed knowing that this is optimising their upwind or
downwind performance.
Whilst VMG is an important part of sailing technique, it
should be checked by someone other than the helmsman.
This person should develop a feel for the boat speeds when
the greatest VMG is attained and then communicate these to
the helmsman.
2.9.55 Wind Angle to the Mast
Menu heading: PERFORM
Function text: W/A MAST
Update rate: 1Hz
Units: Degrees
Note
1. Requires mast rotation sensor
When the mast rotation sensor is fitted, this measures the
apparent wind angle to the mast's centreline, thus giving the
actual attack angle of the entry of the sail to the wind.