Vrm; Fig. 3-16 Range Soft Keys; Fig. 3-17 Variable Range Marker - Raymarine L750 Operating Handbook

Chapter 3: Operating Instructions
Here is a list of the possible range settings
In feet:
In fathoms:
In meters:
Note – If the Sidelooker feature is turned on, there is an extra Soft Key
which allows you to set the range for the Sidelooker. See Section 4.

Fig. 3-16 Range Soft Keys

Fig. 3-17 Variable Range Marker

VRM

"VRM" means "Variable Range Marker." On this unit, the VRM feature
offers a way of finding the depth of an object on the display. To use the
feature, press the VRM button to create a horizontal line on the display.
5, 10, 15, 20, 30, 40, 50, 60, 80, 100, 150, 180, 200,
250, 300, 400, 600, 800, 1000, 1500, 2000, 2500
1, 2, 3, 4, 5, 8, 10, 15, 20, 25, 30, 40, 50, 60, 80, 100,
150, 200, 250, 300, 450
2, 4, 6, 8, 10, 15, 20, 25, 30, 40, 50, 60, 80, 100, 150,
200, 300, 400, 500, 600, 800
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VRM depth
VRM marker