Furuno NAVNET 1833 - Manual (Page 60)

2. RADAR OPERATION
2-26
2.18.4 Echo trail mode
Echo trails may be shown in Relative or True motion. (True motion requires
speed and heading inputs.)
1. Press the [MENU] key.
2. Press the RADAR DISPLAY SETUP key.
3. Choose TRAIL MODE, then press the EDIT soft key.
TRAIL MODE
▲
¡ TRUE
¤ RELATIVE
▼
Trail mode window
4. Select TRUE or RELATIVE as appropriate, then press the ENTER soft key.
5. Press the [MENU] key to close the menu.