Furuno CI-35 Operator's Manual page 10

CALIBRATING COURSE OFFSET (Automatic)
A. When ground-tracking is attainable:
1. Make sure the navaid (GPS) is working correctly and accurately.
2. On CI-35/35H, select ground tracking mode. (Press the TRACKING MODE key to see the
"GT" mode indication on the display.)
3. In Menu 4, set 'CRS CAL MODE' to "GT".
4. Run your boat at a speed about 10 kts, keeping the same direction. To minimize the effect of
gyro speed error, it is desirable to run along parallels (i.e., eastward or westward).
5. In Menu 4, place the cursor on "START" ('CRS CAL EXEC') and then press the EVENT
key. As soon as you press the EVENT, "0.0" should appear in reverse text at the upper-right
part of the display. After 2 mile-run, the display will show the course calibration angle
(result of calculation) in normal text.
Lead run
B. When ground-tracking is unattainable:
1. Make sure the navaid (GPS) is working correctly and accurately.
2. On CI-35/35H, select nav-aided mode. (Press the TRACKING MODE key to see the "NAV"
mode indication on the display.)
3. In Menu 4, set 'CRS CAL MODE' to "NAV".
4. Run your boat at a speed about 10 kts, keeping the same direction. To minimize the effect of
gyro speed error, it is desirable to run along parallels (i.e., eastward or westward).
5. In Menu 4, place the cursor on "START" ('CRS CAL EXEC') and then press the EVENT
key. As soon as you press the EVENT, "0.0" should appear in reverse text at the upper-right
part of the display.
6. When the boat has run for 5 minutes, turn your heading almost 180˚ and steer back to the
start point. After 10 minute-run, the display will show the course calibration angle (result of
calculation) in normal text.
Lead run
viii
Course made good
by CI-35/35H plus Gyro
Start Point
EVENT
pressed
Start Point
EVENT
pressed
calibrated to equalize
these tides
Course made good
by ext. navaid (GPS)
2 n.m. (approx)
5 minutes
(half way)
Course calib. angle
calibrated to fit these
two courses made good
off the track by 5 to
10 not to get on
own wake