Annex – Guidance on the Bridge Navigational Watch Alarm System (BNWAS) Auto Function
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Annex – Guidance on the Bridge Navigational Watch Alarm System (BNWAS) Auto Function

  1 SOLAS regulation V/19.2.2.3 requires the provision of a Bridge Navigational Watch Alarm System (BNWAS), which shall be in operation whenever the ship is under way at sea, whilst SOLAS regulation V/18 requires BNWAS to conform to appropriate performance standards not inferior to those adopted by the Organization (i.e. resolution MSC.128(75)).

  2 Resolution MSC.128(75) – Performance standards for a bridge navigational watch alarm system (BNWAS), section 4.1.1.1 states that "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)".

  3 At the fifty-fifth session of the NAV Sub-Committee, concerns were raised with respect to the use of the Automatic mode and NAV 55 concluded that the Automatic mode of the performance standard was therefore not usable on a ship 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 with the performance standards, therefore, equipment would include the Automatic mode, despite that this operational mode should not be used on ships which are subject to the SOLAS Convention.

  4 From the operational point of view, automatic interface with activation of the ship's heading or track control system (HCS/TCS) is a superfluous function because SOLAS regulation V/19.2.2.3 requires the BNWAS to be in operation whenever the ship is under way at sea. This creates an inconsistency between SOLAS regulation V/19.2.2.3 and the "Automatic mode" provisions in the performance standard. In addition, from the technical point of view, it is noted that this issue is also addressed in the "note" to section 3.1.1 of IEC 62616:2010 – Maritime navigation and radiocommunication equipment and systems – Bridge navigational watch alarm system (BNWAS), which states:

  • "NOTE: The Automatic mode is not suitable for use on a ship conforming with regulation SOLAS V/19.2.2.3 which requires the BNWAS to be in operation whenever the ship is underway at sea" .

  5 Accordingly, as an interim measure and pending a revision of the Performance standards for a bridge navigational watch alarm system (BNWAS) – (resolution MSC.128(75)), the automatic operational mode, if it is available, should not be used.

Parent topic: MSC.1/Circular.1474 – Guidance on the Bridge Navigational Watch Alarm System (BNWAS) Auto Function – (23 May 2014)
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