EVENTS:Sea Asia, 9-11th April 2019Sea Asia, 9-11th April 2019

MD76HM Heading Monitor Unit & Off Course Alarm

Heading Monitor which triggers an Alarm whenever the vessel deviates from a chosen course by more than a preset amount.

OVERVIEW – Heading Monitor

The MD76HM Heading Monitor from MARINE DATA is an off-course safety alarm designed for seagoing vessels. An audible and visible alarm is activated at the steering position whenever the vessel deviates from a chosen course by more than a preset amount (in degrees). A Heading Monitor is an important aid to safety at sea and is a requirement of IMO whenever an autopilot is installed.

Compact and rugged, the MD76HM Heading Monitor is ideal for locations where the available space is limited. It may be either bulkhead mounted or panel mounted and is finished in RAL9005 Jet Black to complement other marine navigation equipment.

The MD76HM Heading Monitor from MARINE DATA: flexible in application, easy to install and simple to maintain.


  • On/Off activation can be controlled by an autopilot system
  • Remote trigger circuit for a remote alarm sounder
  • Automatic changeover from main to backup power supply
  • Audible and visual alarm in the event of a main power failure
  • A built-in test function
  • Dimmer control rotary switch for panel indicators
  • Accepts NMEA 0183 heading data with heading types HDT, HDG and HDM


  • Ideally suited to workboats, tugs and fishing vessels
  • Provides the IMO Requirements of a Heading Monitor for an Autopilot



  • Weight: 8 kg
  • Dimensions: H 143 mm; W 240 mm; D 173 mm (on bracket)
  • Mounting: Panel mount or optional Bulkhead mount
  • Connections: 4x watertight cable glands; 2x 12-way internal screw terminals
  • Construction: Aluminium alloy enclosure
  • Finish: RAL9005 Jet Black, fine texture


  • Power Supply: 24 V dc main supply; 24 V dc backup supply
  • Data Input: RS422 NMEA 0183; 4800 Baud
  • Data Sentences: HDT, HDG and HDM; detected on start‑up in descending order of priority


  • Performance: ±1° accuracy
  • Follow-Up Rate: Limited by compass follow-up rate
  • Data Outputs: Audible and Visible alarm indications
  • Alarm Loudness: 90 dB at 30 cm
  • Adjustment: The Course Width Selector sets an Allowable Course Deviation of 4°, 6°, 8°, 16° or 20°


  • IP rating: IP54
  • Operating temp: -15°C to +55°C
  • RoHS: Compliant
  • Compass: Safe distance 50 cm


  • Conforms with: IEC 60945


  • Supplied: Panel Mounting Kit
  • Heading: The heading to be monitored is relative to the current heading data in use


  • Optional Bulkhead Mounting Kit (trunnion) MD76TB SKU F076100

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