Furuno FCR-2107 Series Operator's Manual page 50

2. Radar Operation
When own ship reaches a point corresponding to 75% of the radius of the display, own ship position is automatically
reset to a point of 75% radius opposite to the extension of the heading line passing through the display center. You
can also reset the own ship symbol manually by pushing the CU/TM RESET key, or use the trackball to select the
TM Res box at the bottom right corner of the display then push the left button.
Heading
line
(a) True motion
is selected
2-8
North
marker
(b) Own ship has reached a
point 75% of display radius
(c) Own ship is automatically
reset to 75% of radius