IS15 General Manual
16
20220760G
Notes !
1.
The Wind Direction is calculated from available heading
data. The wind direction given is the effective wind direction
over the water. The display will be most accurate after a
period on one heading, however, it will respond rapidly to
course changes.
2.
If there is no heading data, but Course Over Ground (COG)
data is available then the Wind Direction is calculated from
the Course Over Ground. In this case there is compensation
for the tide, and the wind direction given is the effective wind
direction over the ground. However the display will not be
accurate after a course change, and will require a period on
one heading before it is correct. (Any errors in the
Navigation Receiver’s fix will degrade the accuracy of the
wind direction.)
3.
The Wind Direction is referenced to either Magnetic or True
North as selected for the heading. The data can be converted
from one to the other if the local magnetic variation is
available (page 19).
4.
Note that the ‘TRUE’ and ‘APPARENT’ readings that are
shown in this group of screens relate to the Wind Speed and
Angle, and not the Wind Direction.
2.7
Screen Group 3: VMG
There are three screens in this group.
Screen 1
VELOCITY MADE GOOD (VMG) TO WIND
BOAT SPEED
APPARENT WIND ANGLE
•
The upper screen section displays ‘VMG’, the VMG to wind
value and the unit (e.g. ‘kts’). The VMG display shows the
Velocity Made Good into the wind, this is shown as a
positive speed if the vessel is travelling upwind, and as a
negative speed if the vessel is travelling downwind.
•
The middle section displays ‘BOAT’, the Boat Speed reading
and the unit (e.g. ‘kts’).
•
The lower screen section displays ‘WIND APP’, a wind
direction icon and the apparent wind angle reading.
Screen 1 has a sub screen for setting the boat (water) speed
damping.
Refer to page 11.
