Autopilot Systems for Ship


Autopilot Type NT921 MKII

Specifically designed for small professional vessel use (typically 11-20m LOA) the NT921 MKII Autopilot provides a powerful combination of steering system control and interface facilities based on an extremely intelligent Control Unit which is clearly marked and simple to operate.

Accordingly, the NT921 MKII offers Navitron steering expertise in a robust and compact package which includes the following special features: –

  • Dual Channel Heading Inputs : –
    NMEA 0183 Direct and Mag Sensor Coil
  • Built in Radio Navigator Interface for selectable (HI and LO) automatic track steering between waypoints.
  • Fully automatic stability compensation for variations in rudder speed.
  • Three Heading output Channels for Radar Stabilisation etc. (NMEA, Furuno & Step by Step).

A microprocessor based Autopilot for magnetically and GPS compass / track steered vessels from typically 10 – 20m (30 – 65ft).

Model NT921 MKII
Model NT921 MKII

Typical Applications : 

  1. Workboats  
  2. Fishing Vessels
  3. Survey Units
  4.  Patrol Craft

Standard Features : 

  1. Full P.I.D Intelligence,
  2. Servo driven Heading Repeater (Standby mode),
  3. Dual Course Setting and Steer on Lock on facility,
  4. Full Automatic Permanent Helm,
  5. Digital displays of Heading, Rudder Angle and Cross Track Error (CTE),
  6. Operator variable control panel illumination,
  7. 11-40Vdc Power Supply compatibility,
  8. Solid State Output stages. (11-40Vdc/5A max),
  9. Full range menu driven installation presets.

Optional Equipment : 

  1. Rudder Indicators,
  2. Power Steer Controls,
  3. Off Course Alarm,
  4. Watch Alarm,
  5. Universal Relay Box,
  6. Analogue Steering Interface,
  7. Dual Steering Interface,
  8. Bowthruster Interface.

    NT921 MKII Autopilot Outline & Mounting Dimensions

Straightforward operation is a key feature of the NT921 MKII thus operator controls are kept to a minimum and are clearly identified by control panel markings which are red backlit for night viewing via a variable intensity illumination control.

A conventionally marked Course Selector permits simple course selection which is automatically corrected to maintain the vessel on a specified track when connected to a GPS or Track Plotter programmed with a track based on predetermined waypoints.

In addition to Track data, the NT921 MKII will also accept NMEA heading data directly from GPS compass systems etc. When dual heading inputs are employed (NMEA + mag sensor coil) the priority source is installation programmable with automatic changeover in the event of primary source failure.

Suitable for console or bracket mounting, the NT921 MKII Control Unit is intended for wheelhouse location and is supplied complete with Heading Sensor Coil and Rudder Reference Unit for installation to solenoid hydraulic systems (11-40Vdc/5A max).

High voltage solenoids (110/220Vac/dc) can also be accommodated via the inclusion of an optional Universal Relay Box type NT920URB.

Alternatively analogue signal control of water jets or analogue steering machines requiring -10v/+10v inputs can be configured via the inclusion of a Navitron Analogue Steering Interface (NT990ASI).



Outline Specification 

Power Consumption12V24V
Illumination (max)5.8 W7.0W
Solenoid Switch Ratings
Voltage11-40 Vdc
Current5A (max)
Switchline PolarityInstallation Selectable
Switch TypeSolid State
Operator controls
Autopilot Mode Switch
RadioNav Mode Switch
IlluminationRed Backlight
Panel Displays
Rudder Angle2 Digit LCD + LCD Bar
Heading IndicatorServo Card In Standby Mode and 3 Digit LCD Display
XTE IndicatorLED
Autopilot ModeLED Indication of Standby, Auto & Remote
RadioNav ModeLED Indicator of XTE & Auto Heading Correct
XTE3 Digit LCD Display
Correction Angle2 Digit LCD Display
(Via automatic Heading display updates at 15 second intervals)
Panel Alarms
RemoteLED + Audible
Data Input Fail (XTE)LED + Audible
Max Correction (XTE)LED + Audible
MechanicalNT921 MKII Control Unit
Width259 mm
Height176 mm
Depth behind bezel115 mm
Weight3.9 Kg


  1. Hi sir
    I Amour Jean Francis KEMMEGNE from Central African
    The n921 auto pilot show the message No data
    What can i do to solve the problem i am électronician
    I need your help

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