Nav change limit, Rudder play compensation – Simrad AP25 User Manual
Page 126

Simrad AP25 Autopilot
124
20221495F
NAV change limit
In NAV mode, when the 
required course change at the 
approaching waypoint is 
bigger than the set limit, you 
are prompted to verify that the 
upcoming course change is 
acceptable. The limit can be 
set to 10°, 20° or 30°. 
Default: 10° 
Rudder play compensation.
(Only applicable when configured for Virtual feedback)
Notes!
1. To obtain the best possible steering performance the said
procedures must be performed in the following order: 
- Perform an autotune at 6-8 knots in calm sea. 
- If necessary fine tune the Counter Rudder parameter (see 
page 126) at cruising speed (LO value) and at slow speed 
(HI value) 
- Use the response control to obtain the best possible course 
keeping (page 56). 
2. If the autopilot performance is found satisfactory when the
above has been completed, skip the following rudder play 
compensation procedure. The rudder play compensation 
procedure is only necessary if the steering gear is sloppy. 
Using this procedure when not required may interfere with 
the steering algorithms and result in poorer steering instead 
of providing improvements. 
A play in the steering gear will always reduce the steering 
performance of the autopilot. The best result is obtained when 
sloppy linkages are repaired and this is the recommended course 
of action. 
Note !
With a rudder feedback unit installed the effect of the rudder 
play is significantly lessened. 
When rudder play still exists and there is no feedback unit 
installed, the autopilot will need some assistance from the 
installer to compensate for this. The effect of the rudder play is 
