What is BNWAS, its Performance & Carriage Requirements?

Written by Amit Sharma
What is BNWAS (Bridge Navigational Watch Alarm System)?

A Bridge Navigational Watch Alarm System,( BNWAS) , is an automatic system which sounds an alarm if the watch officer on the bridge of a ship falls asleep, becomes otherwise incapacitated, or is absent for too long a time. The BNWAS is automatically engaged when the ship’s autopilot is activated.

The bridge navigational watch alarm system shall be in operation whenever the ship is underway at sea; 

Bridge Navigational Watch & Alarm System – BNWAS is a monitoring and Alarm system which notify other navigational officers or master of the ship if the officer on watch (OOW) does not responds or he/she is incapable of  performing the watch duties efficiently which can lead to maritime accidents.

The minimum requirement for a BNWAS under International Maritime Organization standards is to have a dormant stage and three alarm stages, except that on a non-passenger vessel, the second stage may be omitted. 

Stage 1: When the autopilot is engaged, the bridge officer is required to signal his presence to the BNWAS system every 3 to 12 minutes in response to a flashing light, either by moving an arm in front of a motion sensor, pressing a confirmation button, or directly applying pressure to the BNWAS centre.

Stage 2: When a confirmation signal fails to occur within 15 seconds in Stage 1, an alarm will sound on the bridge, and if there is still no confirmation signal after a further 15 seconds, in the captain’s and the first officer’s cabins. One of them must then go to the bridge and cancel the alarm.

Stage 3: If neither the captain nor the first officer cancels the alarm within a specified time period (between 90 seconds and 3 minutes depending on the size of the vessel), an alarm will sound in locations where other personnel are usually available.

About the author

Amit Sharma

Graduated from M.E.R.I. Mumbai (Mumbai University), After a brief sailing founded this website with the idea to bring the maritime education online which must be free and available for all at all times and to find basic solutions that are of extreme importance to a seafarer by our innovative ideas.