Furuno GD-1700C - Manual (Page 116)

3. RADAR OPERATION
3-22
3.17 Using the Offset EBL
The offset EBL can be used to predict a potential collision course. It can also be
used to measure the range and bearing between two targets.
3.17.1 Predicting collision course
The procedure below may be used to check if a radar target is on a potential
collision course with your vessel.
1. Press the [EBL/VRM] key to show the EBL/VRM soft keys.
2. Press the EBL1 ON soft key to turn on the EBL1.
3. Press the OFFSET soft key. The origin of EBL1 moves to the cursor position
and an “X” appears at the cursor position.
4. Use the cursor pad to place the cursor on the radar target which looks like it
might be on a collision course with own ship.
5. Push the [ENTER] knob to fix the origin position.
6. After waiting for a few minutes (at least three minutes), rotate the [ENTER]
knob so the EBL bisects the target at the new position. If the target tracks
along the EBL towards the center of the display (your ship’s position), the
target may be on a collision course with your vessel.
7. To cancel the offset EBL, press the OFFSET soft key.
.250/ 319.9
°
M .125nm
SP
H-UP
Initial target
position
Target tracked
here
+
359.9 ° R
.0.240nm
EBL
VRM
EBL1
ON
VRM1
ON
OFFSET
EBL2
ON
VRM2
ON
EBL1
45.0
°
R
VRM1
-.---nm
Predicting collision course with the offset EBL