Bridge navigational watch alarm system (BNWAS) requirements

The bridge navigational watch alarm system shall be in operation whenever the ship is underway at sea. A bridge navigational watch alarm system (BNWAS) installed prior to 1 July 2011 may subsequently be exempted from full compliance with the standards adopted by the Organization, at the discretion of the Administration (SOLAS 19.2.2.3) Note: A bridge watch alarm system is a device which triggers an alarm if an Officer on Watch (OOW) becomes incapable of performing the OOW’s duties. IMO has adopted the performance standard as MSC. 128 (75) and there are ships which have already installed the equipment on a voluntary basis. The BNWAS should be operational whenever the ship’s heading or control system is engaged, unless inhibited by the master, however the BNWAS should also be operational when the vessel is at anchor.
Alternative reset arrangements may be incorporated to initiate the reset function from other equipment on the bridge capable of registering operator actions in positions giving proper look out. (MSC. 128 (75)). NOTE There should NOT be a reset function on any equipment including the ECDIS that is located in the chartroom outside of positions where a proper look out can be maintained.
With respect to testing of the equipment: the mains power supply for the BNWAS to be simulated to fail to establish whether the equipment is still operational, and alarms generated on main power failure. There is NO requirement to ‘trip’ the backup battery supply.