MSC.128(75) Performance Standards for a Bridge Navigational Watch Alarm System (BNWAS)


Resolution MSC.128(75)


(adopted on 21 May 2002)




RECALLING Article 28(b) of the Convention on the International Maritime Organization concerning the functions of the Committee,


RECALLING ALSO resolution A.886(21), by which the Assembly resolved that the function of adopting performance standards and technical specifications, as well as amendments thereto shall be performed by the Maritime Safety Committee and/or the Marine Environment Protection Committee, as appropriate, on behalf of the Organization,


RECOGNIZING that, many operational bridge-related marine accidents could be averted if an effective and operational Bridge Navigational Watch Alarm System (BNWAS) was fitted to vessels,


RECOGNIZING FURTHER that, by the use of a Bridge Navigational Watch Alarm System (BNWAS) warnings will be given in case of the incapacity of the watchkeeping officer due to accident, sickness or in the event of a security breach, e.g. piracy and/or hijacking,


NOTING that the installation of such equipment is a relatively low-cost and an effective means of avoiding operational navigational accidents,


RECOGNIZING the need to prepare appropriate performance standards for BNWASs,


HAVING CONSIDERED the recommendation on the performance standards for BNWASs made by the Sub-Committee on Safety of Navigation at its forty-seventh session,


1. ADOPTS the Recommendation on Performance Standards for a Bridge Navigational Watch Alarm System set out in the Annex to the present resolution;


2. RECOMMENDS Governments to ensure that BNWASs installed on or after 1 July 2003, conform to performance standards not inferior to those specified in the Annex to the present resolution.







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. Additionally, the BNWAS may provide the OOW with a means of calling for immediate assistance if required. The BNWAS should be operational whenever the ship's heading or track control system is engaged, unless inhibited by the Master.



IMO resolution A.830(19)

Code on alarms and indicators

IMO MSC/Circ.982

Guidelines on Ergonomic Criteria for Bridge Equipment and Layout

IMO resolution A.694(17)

General Requirements* for ship-borne radio equipment forming part of the Global Maritime Distress and Safety System (GMDSS) and for Electronic Navigational Aids


* IEC Publication 60945




Bridge — Wheelhouse and bridge wings




4.1 Functionality


4.1.1 Operational Modes The BNWAS should incorporate the following operational modes:


- 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)


4.1.2 Operational Sequence of Indications and Alarms Once operational, the alarm system should remain dormant for a period of between 3 and 12 min (Td). At the end of this dormant period, the alarm system should initiate a visual indication on the bridge. If not reset, the BNWAS should additionally sound a first stage audible alarm on the bridge 15s after the visual indication is initiated. If not reset, the BNWAS should additionally sound a second stage remote audible alarm in the back-up officer's and/or Master's location 15 s after the first stage audible alarm is initiated. If not reset, the BNWAS should additionally sound a third stage remote audible alarm at the locations of further crew members capable of taking corrective actions 90 s after the second stage remote audible alarm is initiated. In vessels other than passenger vessels, the second or third stage remote audible alarms may sound in all the above locations at the same time. If the second stage audible alarm is sounded in this way, the third stage alarm may be omitted. In larger vessels, the delay between the second and third stage alarms may be set to a longer value on installation, up to a maximum of 3 min, to allow sufficient time for the back-up officer and/or Master to reach the bridge.


4.1.3 Reset Function It should not be possible to initiate the reset function or cancel any audible alarm from any device, equipment or system not physically located in areas of the bridge providing proper look out. The reset function should, by a single operator action, cancel the visual indication and all audible alarms and initiate a further dormant period. If the reset function is activated before the end of the dormant period, the period should be re-initiated to run for its full duration from the time of the reset. To initiate the reset function, an input representing a single operator action by the OOW is required. This input may be generated by reset devices forming an integral part of the BNWAS or by external inputs from other equipment capable of registering physical activity and mental alertness of the OOW. A continuous activation of any reset device should not) prolong the dormant period or cause a suppression of the sequence of indications and alarms.


4.1.4 Emergency Call Facility


Means may be provided on the bridge to immediately activate the second, and subsequently third, stage remote audible alarms by means of an "Emergency Call" push button or similar.


4.2 Accuracy


The alarm system should be capable of achieving the timings stated in section 4.1.2 with an accuracy of 5% or 5s, whichever is less, under all environmental conditions.


4.3 Security


The means of selecting the Operational Mode and the duration of the Dormant Period (Td) should be security protected so that access to these controls should be restricted to the Master only.


4.4 Malfunctions, alarms and indications


4.4.1 Malfunction


If a malfunction of, or power supply failure to, the BMW AS is detected, this should be indicated. Means shall be provided to allow the repeat of this indication on a central alarm panel if fitted.




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