The purpose of the Bridge Navigation Watch Alarm System (BNWAS) is to ensure that a vessel is under the control of the Officer of the Watch (OOW) at all times and to ensure that the wheelhouse is never unmanned. The OOW must reset the BNWAS within a set time period. The BNWAS is essential for companies running a "one man bridge" operation, where the vessel is reliant on one OOW to ensure the vessel continues on a safe passage. Should the OOW become unable to interact with the BNWAS the system will enter a sequence of alarm stages:
Stage 1 Audible and visual alarm local to the wheelhouse only Stage 2 Additional audible and visual alarm in chosen officers quarters Stage 3 Additional audible alarm ship-wide
In addition to the standard "push to reset" controls the KW810 has the option of the KW-810P PIR Motion Sensor. When the sensor detects movement by the OOW it will automatically reset the BNWAS counter, leaving the OOW free to carry out his normal duties without the concern of resetting the BNWAS manually every 3-12 minutes.
The AMI BNWAS is fully type-approved and meets the requirements of IMO Resolution MSC.282(86) (adopted June 2009) which states that BNWAS will be mandatory on vessels on all voyages as follows:
1 July 2011 Cargo ships of 150 gross tonnage and greater and all passenger ships constructed after this date, irrespective of their size. 1 July 2012 Passenger ships irrespective of their size constructed before 1 July 2011, not later than 1st survey after 1 July 2012. 1 July 2012 Cargo ships of 3000 gross tonnage and upwards constructed before 1 July 2011, not later than 1st survey after 1 July 2012. 1 July 2013 Cargo ships 500 gross tonnage and upwards but less than 3000 gross tonnage constructed before 1 July 2011, not later than 1st survey after 1st July 2013. 1 July 2014 Cargo ships of 150 gross tonnage and upwards but less than 500 gross tonnage constructed before 1 July 2011, not later than 1st survey after 1 July 2014.