
OPERATOR MANUAL
AP28
AUTOPILOT
20222527 / A Sw.1.1
English
A
P
2
8

2 | AP28 Manual
Copyright
All rights reserved. No part of this document may be
reproduced or otherwise copied without prior written
permission of Navico Holding AS.
© 2007 by Navico Egersund AS
About this manual
Rev. A
28.11.07 First issue
This manual is intended as a reference guide for
operating and maintaining the Simrad AP28 autopilot.
An autopilot is a complex control system so please take
time to read this manual to get a thorough understanding
of the operation, the system components and their
relationship to a complete AP28 autopilot system.
In this manual, names of menu commands, dialog box
text and keys are written in boldface (e.g. Main menu,
Setup command, Left key).
Important text that requires special attention from the
reader is emphasized as follows:
Used to draw the reader’s attention to a comment or
some important information.
Used when it is necessary to warn personnel that a
risk of damage to the equipment or hazard exists if
care is not exercised.

AP28 Manual | 3
Content
1 System description ..................................... 7
1.1 General ..................................................7
1.2 System components.................................8
1.3 AP28 Control Unit.....................................8
1.4 Autopilot Computer ..................................9
1.5 Rudder Feedback unit...............................9
1.6 Heading Sensors.................................... 10
1.7 Optional equipment................................10
1.8 Software record.....................................10
2 Operation.................................................. 11
2.1 Overview ..............................................11
2.2 ON/OFF ................................................14
2.3 Backlighting ..........................................15
2.4 Standby mode.......................................16
2.5 Automatic steering.................................17
2.6 NoDrift mode.........................................36
2.7 Navigating with the AP28 ........................37
2.8 Wind vane steering (sailboats)................. 41
2.9 Wind steering and navigation (sailboats) ...45
2.10 Data pages..........................................48
2.11 Multiple station system .........................49
3 Main menu................................................ 51
3.1 Data pages setup................................... 52
3.2 Setup Menu........................................... 54

4 | AP28 Manual
3.3 Remote lock..........................................66
4 Setup at installation.................................. 69
4.1 First time turn on................................... 69
4.2 Installation Menu ...................................70
4.3 Service Information.............................. 102
5 Alarm system.......................................... 105
5.1 Alarm indication................................... 105
5.2 Acknowledging an alarm ....................... 106
5.3 Viewing active alarms........................... 106
5.4 Alarm codes ........................................ 106
6 Trouble shooting..................................... 109
6.1 SimNet status...................................... 109
6.2 System data........................................ 109
6.3 Resets................................................ 110
6.4 Alarms ............................................... 111
7 Maintenance ........................................... 115
7.1 General .............................................. 115
7.2 Control unit......................................... 115
7.3 Autopilot Computer .............................. 115
7.4 Rudder Feedback ................................. 115
7.5 Compass............................................. 116
7.6 Drive unit ........................................... 116
7.7 Exchange of software program............... 116
8 Optional equipment ................................ 117

AP28 Manual | 5
8.1 R3000X Remote Control (NFU)............... 117
8.2 S35 Steering Lever (NFU)...................... 118
8.3 JS10 Joystick (NFU).............................. 118
8.4 AP28 with MSD50 Stern Drive unit.......... 118
9 Glossary.................................................. 121
10 Index.................................................... 125

System description | 7
1 System description
1.1 General
Congratulations on the purchase of your new Simrad
AP28 autopilot system and thank you for selecting what
we feel is the most advanced autopilot system available
on the market today.
The Simrad AP28 autopilot represents yet another step
forward in autopilot technology providing leisure boats
between 30 and 50 feet with a host of features.
The autopilot system can be expanded and enhanced
with a selection of options and accessories.
The brain in the AP28 autopilot system is the single
"intelligent" autopilot computer that communicates on
the proprietary SimNet data and control network to
establish a reliable digital communication and power
distribution between the units in the autopilot system as
well as other Simrad products.

8 | System description
1.2 System components
12/24V Motor supply
Drive unit
Multijoiner
Compass
5,5 m
5 m
RF25 Rudder Feedback
12V SimNet supply
(SimNet cable without terminator)
Autopilot
Computer
Non SimNet
SimNet
Termination
plug
AP28
Control Unit
PWR
NAV WIN DTURN
STBY
DRIFT
NO-
AUTO
MENU
Figure 1-1 AP28 Basic system layo ut
1.3 AP28 Control Unit
PWR
NAV WIN DTURN
STBY
DRIFT
NO-
AUTO
MENU
A compact autopilot control for panel,
bulkhead or bracket mounting. A multifunction
LCD display with two-color backlighting
presents readout of autopilot and navigation
data, tactile keys, dedicated mode keys and
rotary course knob provide simple and precise
operation. It has two SimNet connectors for
system interconnection and control, expansion
and data sharing with other Simrad products.
A NMEA2000 Adapter Cable is available for
interface through a SimNet port.

System description | 9
Multiple control units can be added to the system by
daisy-chaining or drop cable to the SimNet network.
1.4 Autopilot Computer
The autopilot computer is the main unit in the AP28
autopilot system. It contains the steering computer and
drive electronics for the drive unit motor and clutch and
provides interface to other system components. Two
models, AC12 and AC42 are available.
1.5 Rudder Feedback unit
RF25 Rudder Feedback Unit
The RF25 is designed for connection to the SimNet
network. It comes with transmission link and 5 m (16
feet) of SimNet cable with connector.
The RF25 provides rudder angle output to a separate
rudder angle indicator also when the autopilot is
switched off.
RF300 Rudder Feedback Unit (optional)
The RF300 is designed for connection to the autopilot
computer. It comes with transmission link and 10 m (33
feet) of cable. RF300 has a different signal format and
does not offer the same accuracy as RF25.
With an RF300 as rudder feedback there is no output to
separate rudder angle indicators when the autopilot is
off.

10 | System description
1.6 Heading Sensors
RC42 Rate Compass
RC42 is a fluxgate compass with an in tegra ted r ate o f
turn sensor. It provides a significa nt impr ovemen t to th e
dynamic performance of both the autopilot and a
stabilized radar display. A 5 m (16 feet) SimN et cable
with connector is attached.
FC40 Fluxgate Compass (optional)
This is a compact magnetic heading sensor using a
floating ringcore in a fluxgate coil. A 5 m (16 feet)
SimNet cable with connector is attached. The dynamic
performance is second to the RC42.
1.7 Optional equipment
See page 115.
1.8 Software record
When the system is switched on, a status display shows
the software version for the control unit. See page
14.
Software version
Description
SW 1.1.00. First issue

Operation | 11
2 Operation
An autopilot is a very useful navigational aid, but
DOES NOT under any circumstances replace a
human navigator
Do not use automatic steering when:
• In heavy traffic areas or in narrow waters
• In poor visibility or extreme sea conditions
• When in areas where use of autopilot is prohibited by
law
When using an autopilot:
• Do not leave the helm unattended
• Do not place any magnetic material or equipment near
heading sensor used in the autopilot system
• Verify at regular intervals course and position of
vessel
• Always switch to Standby mode and reduce speed in
due time to avoid hazardous situations
2.1 Overview
Figure 2-1 AP28 Front Panel

12 | Operation
Key Description
PWR
Power ON-OFF / Light key
STBY
Standby key
Engage Standby mode
AUTO
Auto key
Engage Auto mode
NO-
DRIFT
NoDrift key
Engage NoDrift mode
NAV
Nav key
Engage NAV mode
WIND
Wind key
Engage Wind mode
TURN
Turn key
Enter turn sub-menu
Tack or gybe in Wind mode
MENU
Menu/Enter key
Enter Main Menu
Enter value, Confirm, O K
Action according to the softkey symbol
Left key
Back, Left, Cancel, Exit
Long press: Return to Main page (operation level 1)
Action according to the softkey symbol
Right key
Next, Right
Action according to the softkey symbol
Up key
Up in menu or list box, Increase
Action according to the softkey symbol
Down key
Down in menu or list box, Decrease
Action according to the softkey symbol

Operation | 13
Port key
Adjust the commanded course or wind angle 1 or 10 degrees
Enable port power steering
Action according to the softkey symbol
Starboard key
Adjust the commanded course or wind angle 1 or 10 degrees
Enable starboard power steering
Action according to the softkey symbol
Softkeys
When the basic operation of the keys is
changed, softkey symbols will be displayed
right above the keys to indicate the
alternate function.
The following softkey symbols are used:
Symbol Action Symbol Action Symbol Action
Ok
Up
Increase
Day
backlighting
Cancel
Down
Decrease
Shallow to
stbd
Enter
Increase
Shallow to
port
Back
Decrease
Installation
Next
Night
backlighting
Present
information
Symbols
Inactive unit, disabled data page
Alarm reminder
Locked

14 | Operation
Operational modes
The AP28 system is capable of the following primary
steering modes: STBY (power steering), AUTO, NoDrift,
NAV, WIND and WIND
NAV
. Each mode except WIND
NAV
have a dedicated key.
The WIND
NAV
mode can only be entered when in WIND
mode.
Each mode provides you with a multifunction mode
display.
User adjustable settings are found in the AP28 Main Menu
(page
51).
Alarms
Alarms are presented in plain text to alert you of system
and external data failure conditions. Alarms are both
audible and visual. The alarm listing is on page
111.
Transfer of command
In a multistation system the command can easily be
transferred from one unit to another by pressing the
active mode key.
AP28 units not in control will display the
icon.
Advanced operation
Refer to the Setup item in the Main Menu page 54 for
information.
2.2 ON/OFF
At first time turn on see page
69.
A single press on the PWR key turns the autopilot
system on and presents the start-up pages.

Operation | 15
• Product name
• Software version and release
date
Software version and release date are examples only.
After approximately 5 seconds, the system is operative
and the unit that was turned on will show the Standby
mode display. Other units in a multistation system will
display
. Control is transferred to any single unit by
pressing its STBY key.
A long press on the PWR key activates the power down
dialog box and the autopilot goes to STBY mode before it
is turned off after 3 seconds.
In an emergency it is possible, on a multistation system,
to turn OFF the system at any control unit by pressing
the PWR key.
Please note that even if the autopilot is turned off, a
small amount of current is drawn from the batteries
unless you throw the circuit breaker.
2.3 Backlighting
The display backlighting may be adjusted at any time.
PWR
1 Press the PWR key
- The Light level overlay window
will be displayed on top of the
current view
2 Press one of the keys as described below to change
the display backlighting:
PWR
a The PWR key to increase the light level by one
step

16 | Operation
b The Up/Down softkeys to increase/decrease
the light level by one step
c The Day/Night softkey to toggle between day
and night profiles
If no adjustment is performed within 3 seconds, the Light
level overlay window will close.
For contrast and day/night settings, refer to page
60.
2.4 Standby mode
STBY mode is the mode that is used when steering the
boat at the helm.
Display informatio n :
• Standby mode
• Current heading 345°M
• Compass source: RC42
• Rudder angle 01° to stbd.
See page
80 about VRF.
Power steering (NFU)
In Standby mode, press any of the PORT or STBD keys.
The Non Follow-up (NFU) display is presented and the
rudder will move as long as the key is pressed.
Activates PORT
rudder command
Activates STBD
rudder command
When a NFU steering lever or remote control is operated,
other control units show (inactive). Refer to section 8
for operation of NFU steering levers or remote controls.

Operation | 17
Alternating rudder angle bargraph
If your autopilot is driving a Simrad
MSD50 Stern Drive, the rudder
angle display will after turn-on
alternate between 10 degrees port
and starboard to indicate that the
(rudder) zero point need be set.
Refer to page
118 to set the zero point.
No rudder angle bargraph
When the autopilot is operating on
Virtual Rudder Feedback (VRF), the
rudder angle bargraph is empty.
2.5 Automatic steering
AUTO (Compass) mode
When the AUTO key is pressed, the AP28 automatically
selects the current boat heading as the set course and
maintains the rudder angle. This gives a bumpless
transfer at the mode change.
• Automatic steering mode
• Set course: 340 degrees
• Compass reading: 339°M
• Heading source: RC42
• Rudder angle: 01° to
starboard
• Speed: 12.8 kn (from log)
• Steering parameter set: LO-A
(Low automatic)

18 | Operation
The AP28 will keep the boat on the set course until a new
mode is selected or a new course is set with the course
knob or the PORT or STBD keys. One revolution of the
course knob equals a 45° course change.
Decrease Increase
Course adjust 1°
(or 10°)/push
Course change
CCW: Decrease CW: Increase
On power boats you may in the Setup menu preset the
keys to change course by 10° per press (see page
165)
Once the course is changed to a new set course, the boat
will automatically turn to the new heading and maintain
the new course.
Heading capture
When in AUTO or NoDrift mode (page 36) heading
capture allows you to automatically cancel the turn you
are in by an instant press on the AUTO key or the
NoDrift key. The autopilot will cancel the turn to
continue on the heading read from the compass the very
moment you pressed the AUTO key or the NoDrift key.
This is a useful feature if you are not sure of the exact
turn you have to make to hit e.g. an inlet or a dock.
• Automatic steering mode
• New “captured” heading: 305°
• Compass reading: 311° M
(magnetic) or T (true)
STBY
Regain manual steering by pressing the STBY key.

Operation | 19
Dodging
The AP28 has no specific dodge key. Simply press STBY
and power steer or use the helm to pass any obstacle.
When you return to AUTO mode within 60 seconds the
following display is shown, offering two alternatives:
Go back to AUTO mode
on previous set course
AUTO
Go to AUTO mode with
current heading as set
course
If your dodging maneuver takes more than 60 seconds,
the autopilot will automatically continue on the current
heading.
Control of steering performance
When operating in an automatic mode the AP28 utilizes
two different sets of steering parameters (HI/LO). The
parameters control the response of the boat at different
speeds or wind directions. The two parameter sets can be
automatically or manually selected, and each set can be
manually adjusted (response adjust).
The speed at which the autopilot automatically changes
from LO to HI parameters (or opposite) is determined by
the "Transition Speed" set in the Installation/
Commissioning/Seatrial menu, page
89. See diagram on
next page.
At no speed input the autopilot defaults to LO steering
parameters when engaging an automatic mode from
STBY. This is a safety feature to prevent oversteering.

20 | Operation
26
24
22
20
18
16
14
12
10
8
6
4
2
0
L
O
r
e
s
p
o
n
s
e
p
a
r
a
m
e
t
e
r
s
H
I
r
e
s
p
o
n
s
e
p
a
r
a
m
e
t
e
r
s
Transition Speed set to 9 Knots
Transition to LO parameters
with increasing s peed: 10 Knots
Transition to HI param eters
with decreasing s peed: 8 Knots
Speed
Display legend
HI-A High response parameters set automatically
LO-A Low response parameters set automatically
HI-M High response parameters set manually
LO-M Low response parameter set manually
Power boats
On power boats the automatic selection of HI or LO is
determined solely by the speed of the boat as shown in
the diagram above.
Sailboats
When sailing in WIND mode, the parameter set is
determined by the speed of the boat and the direction of
the wind as per below.
So if you loose too much speed e.g. when tacking, the
parameters will change to HI to gain sufficient rudder
response. This should be observed when setting the
transition speed on sailboats. See also
Wind response
on page
22.

Operation | 21
Response adjust
The Autotune function in the AP28 is so refined that the
majority of boats will need no further adjustments of the
steering parameters. On some boats, however, or at
particular sea conditions a fine tuning of the steering
parameters may improve the performance of the
autopilot.
The Response control allows you to make this fine tuning
for each of the two (HI/LO) parameter sets. The response
can be set to nine levels. Level 4 is default with
parameter values as set by the Autotune function. If no
Autotune is made (not recommended) the level 4 values
are the factory default values.
A low response level reduces the rudder activity and
provides a more “loose” steering.
A high response level increases the rudder activity and
provides a more “tight” steering.
A too high response level will make the boat start S-ing.
When you access the RESPONSE page the highlighted
Adjust parameter is the one that is active.
MENU
Adjustment of HI and LO values can be performed even
with the boat out of the water.

22 | Operation
Range Change per step Default
1-9 1 4
Wind response (sailboats)
Verify that the difference between Course To Steer (CTS)
and the actual heading is at an acceptable minimum.
If the difference between the set wind angle and the
actual wind angle is too big, increase the ‘Wind response’
to reduce the difference.
If the actual wind angle is S-ing around the set wind
angle, or the rudder activity is too high, the ‘Wind
response’ should be reduced.
MENU
Range Change per step Default
1-9 1 4

Operation | 23
Selection of HI/LO parameters
MENU
The “Manual select” item has three alternatives:
Auto – HI – LO.
• Auto is automatically set by speed input
• HI or LO must be set manually when there is no
speed input
The sub-headline in the display shows the
active parameter set and how it is selected.
Pattern steering (power boats)
The autopilot offers a number of different pattern
steering features when in AUTO mode. There is a one
minute time-out between selecting a turn pattern and
starting the turn. During the time-out period the autopilot
will maintain the set course.
When steering in a turn pattern you may at any time
adjust the variables by pressing the
key.
To exit a turn pattern simply press the AUTO key.

24 | Operation
U-Turn
U-Turn changes the current set course to be 180 degrees
in the opposite direction.
This feature is very useful in a man overboard situation
and whenever you want to steer back on a reciprocal
heading.
TURN
Press either the or key to select the direction to
make the U-Turn and start the turn.
Boat makes starboard U-turn
C-turn
The autopilot provides a continuous turn feature when in
AUTO mode. This may be used for circling fish or a
particular object on the seabed.
C-turn makes the boat turn in a circle with a constant
rate of turn. The user decides whether the C-turn should
be made to port or to starboard.
To enter C-turn mode:

Operation | 25
TURN
Press the
or key to select the direction in which to
make the C-turn and start.
The turn rate (ROT) can be adjusted before the turn is
initiated and during the turn. Increasing the turn rate
yields to a smaller circle and vice versa.
MENU
Turn
parameter
Range
Change per
step
Default Units
Rate of turn 10 - 600 5 90 °/min

26 | Operation
Spiral-turn
The spiral-turn feature may also be used for circling fish
or when searching a particular object on the seabed.
Spiral-turn makes the boat turn in a spiral with a
decreasing or increasing radius.
To enter Spiral-turn mode:
TURN
The “initial” radius can be set before the turn is started.
Press either the
or key to select the direction in
which to make the spiral-turn and start.
During the turn the “change in radius” can be adjusted
and the number of feet or meter is how much the radius
is changed for each circle turned.
If the “change radius” is set to zero, the boat will turn in
a circle.

Operation | 27
MENU
Negative values indicate decreasing radius while positive
values indicate incr e a s ing radius.
Increasing radius Decreasing radius
Turn parameter Range
Change
per step
Default
Initial radius
33 ft - 3281 ft
10 m - 1000 m
10
10
164 ft
50 m
Change of radius
per turn
-164 ft - +164 ft
-50 m - +50 m
5
2
66 ft
20 m
The unit for radius is the same as the unit set for depth
(feet or meter).

28 | Operation
Zigzag-turns
To enter zigzag-turn mode:
TURN
The course change can be set before the turn is initiated
(2-70°).
Press either the
or key to select the direction in
which to make the first course change and start.
While sailing in a zigzag pattern you can alter the course
change, leg distance, and the main course. An arrow
shows the direction of the next course change.
MENU

Operation | 29
Main course
Course change 40°
Initial course change 20°
Leg distance
Turn parameter Range
Change
per step
Default
Course change 4° - 140° 4 28°
Leg distance
82 ft - 9843 ft
25 m - 3000 m
50
25
1641 ft
500 m
The unit for leg distance is the same as the unit set for
depth (feet or meter).
Square-turn
The square-turn feature in AUTO mode can also be made
as rectangle or any pattern where the next turn is 90°.
To enter Square-turn mode:
TURN
Press either the
or key to
select the direction in which to make
the first course change and start.
Leg distance

30 | Operation
You can at any time change the main course.
You can also at any time change the distance of the leg
until the boat makes a new 90° turn.
MENU
Turn parameter Range
Change
per step
Default
Leg distance
82 ft - 9843 ft
25 m – 3000 m
50
25
1641 ft
500 m
The unit for leg distance is the same as the unit set for
depth (feet or meter).