The purpose of a Bridge Navigational Watch Alarm System (BNWAS) is to monitor bridge activity and detect operator disability which could lead to marine accidents. The system monitors the awareness of the Officer of the Watch (OOW) and automatically alerts the master or another qualified OOW if for any reason the OOW becomes incapable of performing the OOW’s duties. This purpose is achieved by a series of indications and alarms to alert first the OOW and, if he is not responding, then to alert the master or another qualified OOW. Amendments to the Safety of Life at Sea Convention (SOLAS), effective from 1 January 2011, require all vessels to be fitted with BNWAS and require that BNWAS should be in operation whenever the ship is underway at sea.



The International Maritime Organisation (IMO) has also adopted performance standards for BNWAS. The recommendations on performance standards state, “The BNWAS should incorporate the following operational modes:
•    Automatic (Automatically brought into operation whenever the ships heading or track control system is activated and inhibited when this system is not activated)
•    Manual ON (In operation constantly)
•    Manual OFF (Does not operate under any circumstances)."

Concerns were raised with respect to the use of the automatic mode and it was concluded that the automatic mode of the performance standard was therefore not usable on a vessel compliant with the SOLAS Convention. It was considered that it would not be possible to change the performance standards before the date at which the carriage requirements came into force (1 July 2011). In order to conform to the performance standards, therefore, equipment would include the automatic mode, despite that this operational mode should not be used on vessels that are subject to the SOLAS Convention.

From the operational point of view, automatic interface with activation of the ship’s heading or track control system is a superfluous function because SOLAS regulation V/19.2.2.3 requires the BNWAS to be in operation whenever the ship Is underway at sea. This creates an inconsistency between SOLAS regulation V/19.2.2.3 and the ‘Automatic mode’ provisions in the performance standard.

From the operational point of view, use of auto function by activation of a vessel’s heading or track control system is a superfluous function because SOLAS regulation V/19.2.2.3 requires the BNWAS to be in operation whenever the ship is underway at sea. This creates an inconsistency between SOLAS regulation and the ‘Automatic mode’ provisions in the performance standards. Accordingly, as an interim measure and pending a revision of the performance standards for BNWAS, the IMO has advised that the automatic operational mode, if it is available, should not be employed.

The full Marine Information Note, which provides a table of details of the upcoming amendments and relevant MCA guidance can be read here.