FURUNO's Bridge Navigational Watch Alarm System monitors watch officer's awareness for early detection of emergency

BNWAS Overview

The purpose of BNWAS (Bridge Navigational Watch Alarm System) is to monitor bridge activity and detect operator disability which could lead to marine accidents.

BNWAS monitors the watch officer’s presence through watch safety system functions.

A watch officer is required to press the button on a Timer Reset Panel or to operate navigation equipment (e.g. ECDIS, Radar, etc.) at certain intervals.

When the officer fails to press the button within pre-set intervals, visual and audible alarms will be generated in the wheelhouse.

If the officer doesn’t respond to the alarm, the system transfers the alarm to the Cabin Panels installed in other sections of the vessel in order to inform backup officers of the watch officer’s incapacity.



  • Meets the IMO resolution MSC.128(75) for BridgeNavigational Watch Alarm System (BNWAS) and MSC.302 (87) for Bridge Alert Management.
  • Monitors the watch officer's presence for maritimecasualty avoidance
  • Transfers the watch alarm to the back-up officer, in the event that the watch officer fails to respond to watch pre-warning or watch alarm
  • Quick access push keys for Navigation Officer's Calland Emergency Call
  • Notifies Back-Up Navigators when TCS (Track ControlSystem, option) has failed
  • Outputs ALR sentence for VDR
  • Optional Motion Detector and Flash Beacon available
  • Set-up menu is protected by password
    • Mode selection (Manual OFF, Manual ON, AUTO)
    • Timer interval (3 to 12 min.)
    • System test
  • Easy to read alphanumeric and graphic presentations
  • Multilanguage available English, Japanese, Russian, Chinese and Korean

For use of languages other than English, please consult with the flag administration and/or class society concerned, before operating BNWAS in those languages.

Timer reset function and Visual indication

The timer reset may be facilitated by one of following means:

  1. Pressing the reset button on the Main Panel/Timer Reset Panel
  2. Provoking the motion sensor
  3. Initiate operation of various navigation equipment

It is important to keep in mind when planning a BNWAS installation that the external devises, which can act as reset devises, need to be located in position where proper lookout can be done by the watch officer.

For the motion sensor, it is critical to locate it in such a way that it cannot be activated by the ships movements. Thus, any curtains present on the bridge deck should not come in the way of the sensor.

For first line of alert, in accordance with IMO Res. MSC.128(75), sufficient number of visual indications (flashing lights) are to be installed and connected.

The visual indications should be visible from all operational positions within the bridge where the OOW (Officer of the Watch) may be stationed to perform his duties.

These positions are made up by, but not limited to, Conning work station, Navigation support work station, steering work station and 2 x docking work stations.

Watch Safety System Sequence

Dormant Period

1. The watch officer in the wheelhouse has to press the button on Timer Reset Panel or operate interfaced equipment at certain intervals. (Dormant period, 3-12 min.)

  • Main Alerm Panel


2. If the watch officer does not press the button on Timer Reset Panel or operate interfaced equipment, the Main Alarm Panel, the Timer Reset Panel and the Flash Beacon (optional) generate the visual alarm in 15 seconds. (Prewarning)

  • Main Alerm Panel
  • Timer Reset Panel
  • Flash Beacon (Option)

1st Stage

3. If the visual alarm is not acknowledged in the prewarning period, the Main Alarm Panel and the Timer Reset Panel generate the audible alarms as well as visual alarm in 15 seconds. (1st Stage)

  • Main Alerm Panel
  • Timer Reset Panel
  • Flash Beacon (Option)

2nd Stage

4. If the officer doesn't respond to the alarm in the 1st Stage, the BR-500 transmits the alarm to the selected Cabin Panels in the selected back-up officer's and/or the captain's room as well as the cabin panels in pubic rooms. (2nd Stage)

  • Main Alerm Panel
  • Timer Reset Panel
  • Flash Beacon (Option)
  • Cabin Panel

3rd Stage

5. If the alarm is not acknowledged within the pre-set time, the system transmits the alarm to all Cabin Panels. (3rd Stage)

  • Main Alerm Panel
  • Timer Reset Panel
  • Flash Beacon (Option)
  • Cabin Panel
  • Cabin Panel

Dormant Period

6. The buzzer stops when the officer presses the [RESET] button. The Main Alarm Panel will reset the timer and return to the dormant period, when the alarm is acknowledged by the watch officer.

  • Main Alerm Panel

Operational modes

BNWAS should incorporate the following 3 operational modes:

  • Automatic: The BNWAS is automatically activated when the vessel is navigating by means of heading or track control system (autopilot/trackpilot), and inhibited as the heading/track control system is deactivated.
  • Manual ON: The BNWAS is always in operation
  • Manual OFF: The BNWAS is turned off completely



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