■ GUIDANCE ON THE BRIDGE NAVIGATIONAL WATCH ALARM SYSTEM (BNWAS) - Manual mode

"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"

BNWAS’s MODE

- Automatic : (Automatically brought into operation whenever the ship's 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)

                                                                   MSC.1/Circ.1474
                                                                       23 May 2014

GUIDANCE ON THE BRIDGE NAVIGATIONAL WATCH ALARM SYSTEM (BNWAS) AUTO FUNCTION

1 The Maritime Safety Committee, at its ninety-third session (14 to 23 May 2014), with a view to providing 
   more specific guidance on the automatic function specified in resolution MSC.128(75) – Performance
   standards for a bridge navigational watch alarm system (BNWAS), approved the guidance, prepared by
   the Sub-Committee on Safety of Navigation at its fifty-ninth session (2 to 6 September 2013), as set out in
   the annex.
2 Member Governments are invited to use the guidance as an interim measure until such time as the
performance standards can be reviewed and revised and, furthermore, bring this guidance to the attention of all parties concerned.

                                                                               ***
                                                                            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.


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