VRM (Variable Range Marker) / EBL (Electronic Bearing Line)
VRM/EBL is used to determine a targets range and bearing from your vessel, or from another target. 2 VRM/EBLs are available which are enabled from the context menu.
or

Centered VRM/EBL
You can use a ‘Centered’ (on your vessel) VRM/EBL to determine the range and bearing of targets in relation to your vessel.
Floating VRM/EBL
You can use a ‘Floating’ VRM/EBL to determine the range and bearing between 2 targets.