Furuno 520 Operator's Manual page 26

3. STEERING MODES
ORBIT
When ORBIT is enabled, your boat will orbit around the boat's current position.
If ORBIT is enabled while in the NAV mode, the boat orbits around the (last)
waypoint. This function requires a plotter or GPS be connected.
To set parameters for ORBIT, operate the autopilot as shown below.
1. Press the [TURN/MENU] key once to show the TURN menu.
2. Rotate the course control knob to select "RADIUS OF ORBIT", and then
press it to circumscribe the value with a double rectangle.
3. Rotate the course control knob to set the radius of orbit (Setting range: 0.05
to 9.99 nm), and then press it.
Note: The radius of orbit may be changed while the orbit mode activates.
4. Reduce boat's speed less than 10 kt.
3-10
Radius of orbit
(set on menu)
The boat's position at the ORBIT is selected.
Example of orbit maneuver (ex. clockwise)
WARNING
Do not use the ORBIT mode in rough sea.
Because the boat turns a 360-degree circle
around the waypoint a large wave or strong
wind can cause the boat to capsize.