NT888G MK2 AUTOPILOT OPERATING MANUAL
1.5
Matching Heading Steered with Heading Set (Section 2.23).
When the Autopilot is engaged, the
AUTOTRIM
(Automatic Permanent Helm – APH)
function continuously monitors any long-term differences between the heading set
and the mean course actually steered. Any long-term difference is automatically
adjusted by the Autotrim (APH) function applying the appropriate amount of
permanent helm.
To speed up this automatic (APH) process: -
(i)
Wait for vessel to settle on steady heading.
(ii) Single Press the
AUTOTRIM SET
key.
(Pressing and holding down the AUTOTRIM key for 5 seconds will switch the
AUTOTRIM function OFF as confirmed by illumination of the corner keypad LED).
1.6 Avoiding
Unnecessary Rudder Correction (Section 2.25).
Frequent rudder movements when the vessel is yawing either side of the set heading
in a seaway indicates that the autopilot sensitivity is set too high for the sea
conditions being experienced. This can cause premature wear of the steering gear
and, whilst an automatically adjusted feature of the full Adaptive operating mode, will
require manual adjustment in the non Adaptive (PID) mode.
To manually decrease the frequency of rudder movement due to yawing: -
(i)
Use the “
CONTROLS
”
key to display the controls menu.
(ii)
Use the “
CONTROLS
” key again to select “YAW” and increase the Yaw
value (1 to 9) using the rotary (+/-) illum. key.
(The normal operational display will resume automatically after a
timeout period of 30 secs.).
NB. Don’t forget to reduce the YAW setting when yawing decreases as the
vessel moves from rougher to calmer sea conditions.
1.7
Altering to a New Heading (Section 2.36).
In full Adaptive operational mode, a course change executed by the Autopilot system
may be controlled by preprogrammed Rate or Radius of Turn data.
These limiting factors can also apply in the non Adaptive (PID) operating mode
provided the Autopilot CONTROLS and LIMITS menus have been programmed and -
for Radius controlled turns - that Speed (SOG) input data is available.
If the existence of safe limiting factors is uncertain, the RUDDER LIMIT function –
which otherwise limits the maximum permissible angle of rudder applied by the
Autopilot – can be employed to produce small rudder angles/slow turns.
