Furuno FR-2125V - Manual (Page 96)

5-14
5.10 Vector Modes
Target vectors can be displayed relative to own ship’s heading (Relative) or north (True).
5.10.1 Ground stabilization and sea stabilization
Target vectors can be ground stabilized or sea stabilized. Sea stabilization is a mode
where own ship and all targets are referenced to the sea using gyro heading and single
axis log water speed inputs in the True Motion mode. Ground stabilization is a mode
where own ship and all targets are referenced to the ground using the ground track or set
and drift inputs. If the accuracy seems unsatisfactory, enter the set and drift correction
(paragraph 5.12).
5.10.2 True vector
Vector mode, True or Relative, is selected with the [VECTOR] key. True vectors are the
predicted true motion of a target as a result of own ship’s direction and speed input. With
true vectors the radar display will look like the one in (a) in the figure below.
In the true motion mode, all fixed targets, such as land, navigational marks and ships at
anchor, remain stationary on the radar screen with vector length zero. But in the presence
of wind and/or current, vectors appear on fixed targets representing the reciprocal of set
and drift affecting own ship unless set and drift values are properly entered.
B
(flashing)
A
Buoy
Own ship
Target on
collision course
(a) True vectors in head-up mode (b) Relative vectors in head-up mode
B
(flashing)
A
Buoy
Own ship
Target on
collision course
Figure 5-9 True and relative vectors in the head-up mode
5.10.3 Relative vector
True vectors are the predicted movement of a target relative to own ship. With relative
vectors the radar display will look like (b) in the figure above.
Relative vectors on targets which are not moving over the ground, such as land, naviga-
tional marks and ships at anchor, will represent the reciprocal of own ship’s ground track.
A target of which vector extension passes through own ship is on the collision course.
(Dashed lines in the figure are for explanation only.)