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SeaTalk Service Manual
12
3.3 Operating Hints
Response Level Adjustment
The ST6000 has three response levels which
enable tighter course keeping to be achieved in
certain cases:-
Level 1 - Automatic Sea State Control
Level 2 - Automatic Sea State Inhibit
Level 3 - Automatic Sea State Inhibit and
counter rudder.
When the autopilot is switched on, the response
level is set to 1. This provides the best
compromise between power consumption and
course keeping accuracy and is suitable for
nearly all situations.
Increasing Response level provides tighter
course keeping at the expense of increased
power consumption and general wear and tear.
It is advisable to use the minimum response
level necessary to achieve the desired course
keeping accuracy. On larger power vessels
level 3 can improve slow speed steering where
the natural yaw damping of the vessel is
reduced.
Note: Level 3 is not recommended for use at
planing speeds or in rough seas.
Track
To make full use of Track control the following
simple points should be observed:-
• Always steer the vessel to within 0.1nm of
track and bring the heading to within 5° of the
bearing to the next waypoint before selecting
Track.
• Always check that there are no navigational
hazards either side of the intended track.
• Always maintain an accurate log with
regular plots to verify the computed position
read from the Radio Navigation Receiver.
• Maintain a proper lookout at all times.
•
Waypoint Advance
If the navigation receiver is transmitting the
waypoint number to the ST6000 the waypoint
alarm will sound whenever a new target
waypoint is selected (see Page 9). When the
alarm is sounding the ST6000 will maintain the
current heading and automatic track control is
suspended. Check the displayed new bearing to
waypoint and when it is safe to turn onto it,
resume automatic track control by simply
pushing Track.
This accepts the new target waypoint and will
steer the vessel onto the new bearing to
waypoint.
The tidal offset may be very different on the new
bearing, and it is good practise to check the
cross track error after a couple of minutes. If the
cross track error continues to increase make a
course adjustment of say 10 degrees in the
direction of the arrow. This will help the Track
control correct more quickly for the new tidal
vector.
Automatic Trim
If Automatic Trim has been selected during
calibration the ST6000 will correct for trim
changes. This correction can take up to one
minute to apply the rudder offset necessary to
restore the set automatic heading. Large course
changes which change the apparent wind
direction, can produce large trim changes. In
these cases the autopilot will not immediately
assume the new automatic heading, and only
settle onto course when the Automatic Trim has
been fully established.
To minimise the inherent time delay the
following procedure may be adopted for large
course changes.
• Note required new heading.
• Select Standby and steer manually.
• Bring vessel onto new heading.
• Select Auto and let vessel settle onto
course.
• Bring to final course with 1° increments.
It is sound seamanship to make major course
changes only whilst steering manually. In this
way any obstructions or other vessels may be
cleared properly and due account taken of the
changed wind and sea conditions on the new
heading prior to engaging the autopilot.
Rudder Gain
The rudder gain level selected during initial sea
trials will normally provide excellent steering
performance over a wide range of conditions.
However, it may be noticed that the autopilot
tends to be a little less stable on northerly
headings in the higher latitudes of the northern
hemisphere (and conversely southerly headings
in the southern hemisphere). This is caused by
the increasing angle of dip of the earth's
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