Collision Assessment By The Offset Ebl; Measuring Range And Bearing Between Two Targets - Furuno FR-1710 Operator's Manual

Range and bearing
to cursor
0.55 NM
15.0 R
No. 2 EBL
(dashed)
EBL
Bearing to
45.5 R
No. 1 EBL 314.0 R
Bearing to
No. 2 EBL
Active marker is
circumscribed.
Figure 1-16 How to measure
bearing by EBL
1.20 Collision Assessment by
the Offset EBL
The origin of the EBL can be placed any-
where with the trackball to enable measure-
ment of range and bearing between any
targets. This function is also useful for as-
sessment of the potential risk of collision.
To assess possibility of collision:
1. Press the [EBL ON] key to display or ac-
tivate EBL No.1.
2. Place the cursor (+) on a target of inter-
est (A in the illustrated example) by oper-
ating the trackball.
3. Press the [EBL OFFSET] key, and the
origin of the active EBL shifts to the cur-
sor position. Press the [EBL OFFSET] key
again to anchor the EBL origin.
4. After waiting for a few minutes (at least 3
minutes), operate the EBL rotary control
until the EBL bisects the target at the new
position (A'). The EBL readout shows the
target ship's course, which may be true
or relative depending on the settings on
the OTHER menu.
Cursor Target
5. To return the EBL origin to the own ship
No. 1 EBL
(dotted)
Cursor
No.1
EBL
Figure 1-17 How to assess risk of collision
1.21 Measuring Range and
1. Press the [EBL ON] key to activate the
2. Turn the EBL rotary control until the EBL
If relative motion is selected, it is also
possible to read CPA (Closest Point of
Approach) by using a VRM as shown in
Figure 1-17(a). If the EBL passes through
the sweep origin (own ship) as illustrated
Figure 1-17(b), the target ship is on a
collision course.
position, press the [EBL OFFSET] key
again.
A
1
A
EBL
140.0 R
(a) Evaluating target ship's course and
CPA in relative motion mode
Cursor
A
1
A
EBL
118.2 R
(b) Target ship on collision course
Bearing Between Two
Targets
No. 1 EBL. Press the [EBL OFFSET] key,
and place the origin of the No.1 EBL on a
target of interest (target 1 in Figure 1-18)
by operating the trackball.
passes through another target of interest
(target 2 in Figure 1-18).
No.1
VRM
VRM
3.85NM
No.1
EBL
VRM
0.00nm
1-15